Academic literature on the topic 'Non conventional yeasts'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Non conventional yeasts.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Non conventional yeasts"
1
Spencer, A. Ragout de Spencer, C. L, J. "Non-conventional yeasts." Applied Microbiology and Biotechnology 58, no. 2 (January 1, 2002): 147–56. http://dx.doi.org/10.1007/s00253-001-0834-2.
Full text
2
Aguiar, C., and C. Lucas. "13-Non conventional yeasts." Current Genetics 35, no. 3-4 (May 1999): 446–59. http://dx.doi.org/10.1007/bf02743091.
Full text
3
Bruner, James, Andrew Marcus, and Glen Fox. "Brewing Efficacy of Non-Conventional Saccharomyces Non-cerevisiae Yeasts." Beverages 7, no. 3 (September 17, 2021): 68. http://dx.doi.org/10.3390/beverages7030068.
Full textAbstract:
Consumer demands for new sensory experiences have driven the research of unconventional yeasts in beer. While much research exists on the use of various common Saccharomyces cerevisiae strains as well as non-Saccharomyces yeasts, there exists a gap in knowledge regarding other non-cerevisiae Saccharomyces species in the fermentation of beer, in addition to S. pastorianus. Here, five distinct species of Saccharomyces from the UC Davis Phaff Yeast Culture Collection, as well as one interspecies hybrid from Fermentis, were chosen to ferment 40 L pilot-scale beers. S. kudriavzevii, S. mikatae, S. paradoxus, S. bayanus, and S. uvarum yeasts were used to ferment wort in duplicate pairs, with one fermenter in each pair receiving 10 g/L dry-hop during fermentation. Analytical measurements were made each day of fermentation and compared to controls of SafAle™ US-05 and SafLager™ W 34/70 for commercial brewing parameters of interest. Finished beers were also analyzed for aroma, taste, and mouthfeel to determine the flavor of each yeast as it pertains to brewing potential. All beers exhibited spicy characteristics, likely from the presence of phenols; dry-hopping increased fruit notes while also increasing perceived bitterness and astringency. All of the species in this study displayed great brewing potential, and might be an ideal addition to beer depending on a brewery’s desire to experiment with flavor and willingness to bring a new yeast into their production environment.
4
Ianieva, O. D., M. O. Fomina, T. V. Babich, G. P. Dudka, and V. S. Pidgorskyi. "Evaluation of Non-Conventional Yeasts Isolated from Rotten Wood for Hydrolytic Activities and Xylose Fermentation." Mikrobiolohichnyi Zhurnal 84, no. 4 (January 17, 2023): 88–97. http://dx.doi.org/10.15407/microbiolj84.04.088.
Full textAbstract:
Hydrolysis of lignocellulose to fermentable sugars and their subsequent conversion to ethanol remain great challenges in the biofuel industry. Rotten wood is first colonized by bacteria and molds that possess strong hydrolases. Yeasts are also an important group of microorganisms that may participate in wood hydrolysis. Decaying wood could provide a rich natural reservoir of yeasts possessing promising hydrolytic activities, including xylanases, cellulases, β-glucosidases, or abilities essential for the fermentation of pentose sugars derived from lignocellulose degradation, especially xylose. Therefore, the aim of this work was to screen yeasts isolated from rotten wood samples for the production of hydrolytic enzymes directed at lignocellulose components and the ability to ferment xylose, L-arabinose, and cellobiose. Methods. Yeast strains were isolated from 22 samples of rotten wood and identified by phenotypic characteristics according to Kurtzman et al. Hydrolytic properties and the ability of the isolated strains to ferment xylose, L-arabinose, and cellobiose were determined using conventional methods. Results. 30 strains of yeasts and yeast-like micromycetes were isolated from 22 samples of rotten wood in the Holosiivskyi Forest, Kyiv. Based on phenotypic properties, most of the isolated yeasts belonged to ascomycetous yeasts and were represented by the following genera: Candida (8 strains), Debaryomyces (5 strains), Kluyveromyces (5 strains), Pichia (5 strains), Scheffersomyces (2 strains), Lachancea, Hanseniaspora, Saccharomyces, and Geotrichum/Galactomyces. A strain of yeast-like non-photosynthetic alga Prototheca sp. was also detected. Most of the isolated microfungi (66.6% isolates) exhibited extracellular β-glucosidase activity, two Candida tropicalis strains possessed weak pectinase and xylanase activity. None of the isolates demonstrated extracellular cellulase activity. Two yeast strains preliminarily identified as Scheffersomyces stipitis were able to ferment xylose at a concentration of 20—100 g/L over a wide temperature range up to 37°C. Acetic acid at 0.25—1% (v/v) concentration resulted in the complete inhibition of xylose fermentation. Ethanol production from xylose up to 6 g/L was observed under the microaerobic fermentation conditions for 24 hr at the substrate concentration 40 g/L, but the subsequent fermentation resulted in decreasing ethanol concentration presumably due to ethanol re-assimilation. None of the isolated strains was capable of fermenting cellobiose or L-arabinose under the microaerobic conditions. Conclusions. This work provides the characterization of yeast microbiota of rotten wood that was represented predominantly by ascomycetous yeasts. The dominant extracellular hydrolytic activity of the isolates was β-glucosidase. This is the first report on the isolation of xylose-fermenting yeasts Scheffersomyces stipitis in Ukraine, which comprised 7% of all the microfungi isolated from rotten wood.
5
Simões, João, Eduardo Coelho, Paulo Magalhães, Tiago Brandão, Pedro Rodrigues, José António Teixeira, and Lucília Domingues. "Exploiting Non-Conventional Yeasts for Low-Alcohol Beer Production." Microorganisms 11, no. 2 (January 26, 2023): 316. http://dx.doi.org/10.3390/microorganisms11020316.
Full textAbstract:
Non-Saccharomyces yeasts represent a very appealing alternative to producing beers with zero or low ethanol content. The current study explores the potential of seven non-Saccharomyces yeasts to produce low-alcohol or non-alcoholic beer, in addition to engineered/selected Saccharomyces yeasts for low-alcohol production. The yeasts were first screened for their sugar consumption and ethanol production profiles, leading to the selection of strains with absent or inefficient maltose consumption and consequently with low-to-null ethanol production. The selected yeasts were then used in larger-scale fermentations for volatile and sensory evaluation. Overall, the yeasts produced beers with ethanol concentrations below 1.2% in which fusel alcohols and esters were also detected, making them eligible to produce low-alcohol beers. Among the lager beers produced in this study, beers produced using Saccharomyces yeast demonstrated a higher acceptance by taster panelists. This study demonstrates the suitability of non-conventional yeasts for producing low-alcohol or non-alcoholic beers and opens perspectives for the development of non-conventional beers.
6
Zhou, Nerve, Thandiwe Semumu, and Amparo Gamero. "Non-Conventional Yeasts as Alternatives in Modern Baking for Improved Performance and Aroma Enhancement." Fermentation 7, no. 3 (June 27, 2021): 102. http://dx.doi.org/10.3390/fermentation7030102.
Full textAbstract:
Saccharomyces cerevisiae remains the baker’s yeast of choice in the baking industry. However, its ability to ferment cereal flour sugars and accumulate CO2 as a principal role of yeast in baking is not as unique as previously thought decades ago. The widely conserved fermentative lifestyle among the Saccharomycotina has increased our interest in the search for non-conventional yeast strains to either augment conventional baker’s yeast or develop robust strains to cater for the now diverse consumer-driven markets. A decade of research on alternative baker’s yeasts has shown that non-conventional yeasts are increasingly becoming important due to their wide carbon fermentation ranges, their novel aromatic flavour generation, and their robust stress tolerance. This review presents the credentials of non-conventional yeasts as attractive yeasts for modern baking. The evolution of the fermentative trait and tolerance to baking-associated stresses as two important attributes of baker’s yeast are discussed besides their contribution to aroma enhancement. The review further discusses the approaches to obtain new strains suitable for baking applications.
7
Spencer, J. F. T., Dorothy M. Spencer, and Nicola Reynolds. "Genetic manipulation of non-conventional yeasts by conventional and non-conventional methods." Journal of Basic Microbiology 28, no. 5 (1988): 321–33. http://dx.doi.org/10.1002/jobm.3620280506.
Full text
8
Capece, Angela, Rossana Romaniello, Gabriella Siesto, and Patrizia Romano. "Conventional and Non-Conventional Yeasts in Beer Production." Fermentation 4, no. 2 (June 1, 2018): 38. http://dx.doi.org/10.3390/fermentation4020038.
Full text
9
Timmermans, Evelyne, Ine Langie, An Bautil, Kristof Brijs, Carolien Buvé, Ann Van Loey, Ilse Scheirlinck, Roel Van der Meulen, and Christophe M. Courtin. "Study of the Fermentation Characteristics of Non-Conventional Yeast Strains in Sweet Dough." Foods 12, no. 4 (February 15, 2023): 830. http://dx.doi.org/10.3390/foods12040830.
Full textAbstract:
Despite the diverse functions of yeast, only a relatively homogenous group of Saccharomyces cerevisiae yeasts is used in the baking industry. Much of the potential of the natural diversity of yeasts has not been explored, and the sensory complexity of fermented baked foods is limited. While research on non-conventional yeast strains in bread making is increasing, it is minimal for sweet fermented bakery products. In this study, the fermentation characteristics of 23 yeasts from the bakery, beer, wine, and spirits industries were investigated in sweet dough (14% added sucrose w/w dm flour). Significant differences in invertase activity, sugar consumption (0.78–5.25% w/w dm flour), and metabolite (0.33–3.01% CO2; 0.20–1.26% ethanol; 0.17–0.80% glycerol; 0.09–0.29% organic acids) and volatile compound production were observed. A strong positive correlation (R2 = 0.76, p < 0.001) between sugar consumption and metabolite production was measured. Several non-conventional yeast strains produced more positive aroma compounds and fewer off-flavors than the reference baker’s yeast. This study shows the potential of non-conventional yeast strains in sweet dough.
10
Dippel, Kevin, Katrin Matti, Judith Muno-Bender, Florian Michling, Silvia Brezina, Heike Semmler, Doris Rauhut, and Jürgen Wendland. "Co-Fermentations of Kveik with Non-Conventional Yeasts for Targeted Aroma Modulation." Microorganisms 10, no. 10 (September 27, 2022): 1922. http://dx.doi.org/10.3390/microorganisms10101922.
Full textAbstract:
Kveik are consortia of yeast used for farmhouse ale production in Western Norway. Yeast strains derived from these mixtures are known, for example, for their high fermentation rate, thermotolerance, lack of phenolic off flavor production (POF-) and strong flocculation phenotype. In this study, we used five single cell yeast isolates from different Kveik yeasts, analyzed their fermentation and flavor production, and compared it with a typical yeast used in distilleries using 20 °C and 28 °C as the fermentation temperatures. One of the isolates, Kveik No 3, showed an impairment of maltotriose utilization and thus a reduced ethanol yield. Kveik fermentations for spirit production often harbor bacteria for flavor enrichment. We sought to improve Kveik fermentations with non-conventional yeasts (NCY). To this end we co-fermented Kveik isolates with Hanseniaspora uvarum, Meyerozyma guilliermondii and Pichia kudriavzevii using 5:1 ratios (Kveik vs. NCY) at 20 °C. The combinations of Kveik No 1 with P. kudriavzevii and Kveik No 1 with Hanseniaspora uvarum showed substantially increased amounts of specific volatile aroma compounds that were previously identified in the NCYs. Our results indicate that Kveik isolates appear to be suitable for co-fermentations with certain NCY to enhance beer or spirit fermentations, increasing the potential of these yeasts for beverage productions.
Dissertations / Theses on the topic "Non conventional yeasts"
1
CAPUSONI, CLAUDIA. "APPLICATION OF NON-CONVENTIONAL YEASTS IN BIOPROCESSES." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/788442.
Full textAbstract:
Sustainability is one of the most pressing challenge of our century, this term is becoming a main keyword of political agendas and more in general of mass media. To increase the “greenness of bioprocesses”, academia and industry, especially in the biotechnological and chemical fields, are focusing their studies with the scope to shift from traditional organic synthesis to new processes with reduced ecological foot-print. A good way to increase sustainability could be set up bioprocesses exploiting microorganisms. Nowadays, companies are searching new organisms that, differently from the well characterized Saccharomyces cerevisiae, show to be more resistant to the harsh conditions commonly occurring in industrial fermentations (high salt concentration, temperature and pressure). Due to their peculiar features, non-conventional yeasts (NCYs) seem to be a promising solution. On the other hand, the disadvantage to use these new organisms is related to the few studies and literature data available, especially compared to S. cervisiae. To fill this gap researchers have started to characterize these new species.
My PhD work had dual aim:
• First to identify good candidates, with specific physiological properties, that could be exploited in bioprocesses.
• Second to characterize new promising enzymatic activities useful for industrial applications.
In the first studies, I focused my attention on marine yeasts. I chose yeasts isolated from this environment, because their use gives the possibility to perform a seawater-based bioprocess saving large amount of fresh waters, reducing both cost and environmental impact. From our laboratory yeasts collection, I selected, for their halotolerance, two different Debaryomyces hansenii strains. Hence mechanisms involved in osmotic stress response have been investigated employing flow cytometry. I showed that hyper-osmotic stress elicits membrane depolarization and decreases membrane permeability to cationic compounds. This phenomenon reduces ions permeability and can negatively affect the uptake of charged substrate during bioprocesses. My research proceeded with the set up of new fermentation protocols in seawater-based media composed by a mixture of hexose and pentose sugar and cheap nitrogen sources. In these conditions we obtained high biomass yield (0.627) in 40 h of bioprocess.
In the second part of my PhD project, I studied NCYs as sources of enzymes. With this aim I identified a nitrilase of marine strain of Meyerozyma guilliermondii, that displayed high activities on aromatic substrate, but also on arylaliphatic and aliphatic ones. These activities were maintained also in presence of high salts concentration. In particular M. guilliermondii nitrilase was able to perform complete dynamic resolution of mandelonitrile in seawaters within in 8 h.
In the last part of my PhD, I identified a novel extracellular and cell-bound phytase activity in Cyberlindnera jadinii. This enzyme is suitable as feed additive, indeed activities at pH 4.5 and 37°C (animals gastric pH and temperature) were 26.25 mU/mgd.w. and 58.36 mU/mgd.w., detected as extracellular and cell-bound respectively. Phytase activities had their optimum at 50°C, reaching 37.2 mU/mgd.w. (extracellular) and 146 mU/mgd.w. (cell-bound).
Data reported in my PhD work suggest that could be interest to proceed with further characterization on NCYs. New “green” bioprocesses characterized by high productivity could be a key for reach sustainability reducing the ecological impact of industrial production.
2
Botti, Alberto. "Genetic and process engineering approaches for improving lipid productivity in the non-conventional oleaginous yeast Cutaneotrichosporon oleaginosus." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19185/.
Full textAbstract:
Gli oli microbici stanno ricevendo sempre più attenzioni come possibile alternativa agli oli vegetali, nel processo di sostituzione dei combustibili fossili. Tuttavia, diversi aspetti necessitano di essere ottimizzati al fine di ottenere oli economicamente competitivi e con caratteristiche chimico-fisiche desiderate. In questa ricerca, sono stati utilizzati due differenti approcci per poter realizzare l’obiettivo preposto. Il primo, si è basato sull’ingegnerizzazione genetica del lievito C. oleaginous, al fine di incrementare la produttività di lipidi e modificare la composizione dei trigliceridi (TAG) sintetizzati. Un protocollo basato su una trasformazione genetica mediata da Agrobacterium è stato utilizzato per sovraesprimere la diacilglicerol trasnferasi (DGA1), l’enzima responsabile dell’ultimo step della sintesi dei TAG, e la Δ9-desaturasi, l’enzima che catalizza la conversione dell’acido stearico (C18:0) in acido oleico (C18:1). La selezione di colonie positive e l’analisi dei mutanti ottenuti ha confermato la buona riuscita della trasformazione. Il secondo approccio ha mirato a studiare l’influenza sulla crescita e sul profilo di lipidi accumulati da C. oleaginous da parte di diversi acidi grassi volatili (VFAs), una materia prima ottenibile da trattamenti di scarti industriali. A questo proposito, sono state utilizzate fermentazioni fed-batch su scala da 1-L basate su glucosio e miscele sintetiche di acido acetico e di VFAs come fonte di carbonio. L’utilizzo simultaneo di acido acetico e acidi secondari ha mostrato come sia possibile stimolare il metabolismo microbico al fine di incrementare l'accumulo di oli e ottenere una composizione chimica lipidica desiderata.
3
Fernandes, Lemos Junior Wilson José. "Evaluation of the Non-Conventional Yeast Starmerella Bacillaris as Biocontrol Agent and Selected Starter for Alcoholic Beverages Production." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3424926.
Full textAbstract:
Yeasts are the main protagonists of the alcoholic fermentation and strongly influence the final characteristics of wine and other alcoholic beverages. In winemaking, during spontaneous fermentation, this process is carried out by indigenous yeasts present on the grape berry and there is a progressive growth pattern of different yeast species, with the final stages invariably being dominated by the alcohol-tolerant strains of Saccharomyces cerevisiae. This species is universally known as the ‘wine yeast’ and is widely preferred for initiating wine fermentations.
From a technological point of view spontaneous grape juice fermentations sometime become stuck or sluggish. This lack of reproducibility and predictability has favored, in the past, the use of yeast starters, generally composed of single strains of S. cerevisiae. Selected S. cerevisiae strains predominate during must fermentation, ensure rapid and reliable grape juice fermentation and, as consequence, consistent and predictable wine quality. However, there has been increasing recognition that wines made with Saccharomyces starter cultures are less complex, producing standardized wines.
In fact, during spontaneous fermentation many other species (the so call non–Saccharomyces yeasts) are present in the grape must and traditionally they were considered deleterious as responsible for some wine off-flavors. Recently, the role of non-Saccharomyces species has been re-evaluated as some of them has been proposed as co-starter to simulate natural must fermentation and to confer greater complexity and specificity to the wine.
In this context, the thesis project was developed in order to select new non-Saccharomyces yeast strains from fermenting musts of overripe grape berries. This stage of grape ripening is characterized to be more susceptible to infection of fungal pathogens such as Botrytis cinerea, whom yeasts present on the berry surface have to compete with. Thirty-six isolates were identified as Starmerella bacillaris isolated from destemmed dried grape of Raboso Piave variety, grown on Bagnoli DOC (Appellation of Origin) area (North-East of Italy). This species is recently proven to be of oenological interest mainly for its high glycerol production. Among them, 14 strains were phenotypically characterized and, for the first time, the antifungal activity of S. bacillaris species against B. cinerea and P. expansum were demonstrated. Moreover, fermentation performances of S. bacillaris strains were evaluated in synthetic, grape and apple musts (for the first time in cider production).
When tested in sequential fermentations with S. cerevisiae this yeast improved the quality of wine and cider. The obtained results indicate that S. bacillaris can be proposed as biocontrol agent on grape in vineyard and during postharvest on stored apples and its presence on fruit surface positively influences the following juice fermentation. Therefore the released of this yeast in the vineyard can increase the sustainability of the production process and the final wine quality. The obtained results provide a solid basis for a new management of yeast used for winemaking and other alcoholic beverage production and open new prospects for a more integrated strategy to increase wine quality.
Then, in this thesis, new S. bacillaris characteristics were evaluated in order to improve alcoholic beverages quality, such as mannoproteins and glutathione production. The quantification of these compounds was determined at the end of fermentation in synthetic must. S. bacillaris was proved to produce different mannoproteins with functional characteristics related to wine stability. Mannoproteins extracted from S. bacillaris cultures presented great potential in increasing the protein stabilization, while if they were produced during sequential fermentation with S. cerevisiae, enhanced the tartaric stabilization. Moreover, in this thesis, a very high glutathione content was demonstrated in S. bacillaris cells after fermentation. Therefore, yeast lees obtained from S. bacillaris fermentations can be proposed as as glutathione source.
In the last part of this thesis the aim was to understand the genomic determinants of S. bacillaris technological traits described in the previous parts. Therefore. the whole-genome sequence of two relevant S. bacillaris strains was performed. By means of genome comparisons between the two S. bacillaris strains and between S. bacillaris, S. cerevisiae and other oenological yeasts, specific genes and metabolic pathways involved in technologically-relevant traits were identified and studied.I lieviti sono i principali protagonisti della fermentazione alcolica e influenzano fortemente le caratteristiche finali del vino e di altre bevande alcoliche. Nella vinificazione, durante una fermentazione spontanea,questo processo viene effettuato da lieviti autoctoni presenti sulla bacca di uva. Alla fine della fermentazione la specie dominate tra i ceppi è Saccharomyces cerevisiae. Questa specie è universalmente conosciuta come il 'lievito di vino' ed è ampiamente preferita per iniziare fermentazioni del vino. Da un punto di vista tecnologico, le fermentazioni spontanee di succo d'uva si sono spesso bloccate. In passato, questa mancanza di riproducibilità e prevedibilità non era favorevole per una produzione di vino di qualità. L’uso di ceppo di lievito, generalmente composti da singoli ceppi come ad esempio S. cerevisiae aiuta a controllare questo problema. I ceppi selezionati di S. cerevisiae predominano durante la fermentazione del mosto, assicurando una rapida e affidabile fermentazione e, di conseguenza, una qualità del vino coerente e prevedibile. Tuttavia, si è accresciuto la convinzione che i vini ottenuti con culture di starter Saccharomyces siano meno complesse, producendo vini standardizzati. Infatti, durante la fermentazione spontanea, nel mosto d'uva sono presenti molte altre specie (i cosiddetti lieviti non Saccharomyces) e tradizionalmente sono stati considerati come responsabili di alcuni sapori no aggradevoli all’assaggio del vino. Recentemente, il ruolo delle specie non Saccharomyces è stato rivalutato poiché alcune di esse sono state proposte come co-avviatore per simulare la fermentazione dei mosti naturali e per conferire maggiore complessità e specificità al vino. In questo contesto, il progetto di tesi è stato sviluppato per selezionare nuovi ceppi di lievito non Saccharomyces da mosti fermentativi di uva passito. Questa fase di maturazione dell'uva è caratterizzata per essere più suscettibile all'infezione di patogeni fungini come Botrytis cinerea. I trentasei isolati sono stati identificati come Starmerella bacillaris , isolati da uve secche della varietà Raboso Piave, coltivate in zona Bagnoli DOC (denominazione d'origine) (nord-est dell'Italia). Questa specie è recentemente dimostrata di interesse enologico soprattutto per la sua elevata produzione di glicerolo. Tra questi, 14 ceppi sono stati caratterizzati fenotipicamente e, per la prima volta, sono stati dimostrati l'attività antifungina delle specie S. bacillaris contro B. cinerea e P. expansum. Inoltre, le prestazioni di fermentazione dei ceppi di S. bacillaris sono state valutate nei mosti sintetici, uve e mele (per la prima volta nella produzione di sidro). Durante la sperimentazione, questo lievito ha migliorato la qualità del vino e del sidro in fermentazioni sequenziali con S. cerevisiae. I risultati ottenuti indicano che S. bacillaris può essere proposto come agente biocontrollo sull'uva nel vigneto e durante la post-raccolta sulle mele conservate: la sua presenza sulla superficie di frutta influenza positivamente la seguente fermentazione dei succhi. Pertanto, il rilascio di questo lievito nel vigneto può aumentare la sostenibilità del processo produttivo e la qualità finale del vino. I risultati ottenuti forniscono una solida base per una nuova gestione del lievito utilizzato per la produzione di vino e altre bevande alcoliche e aprire nuove prospettive per una strategia più integrata per aumentare la qualità del vino. Sono state valutate le nuove caratteristiche di S. bacillaris al fine di migliorare la qualità delle bevande alcoliche, come le manoproteine e la produzione di glutatione. La quantificazione di questi composti è stata determinata alla fine della fermentazione in mosto sintetico. S. bacillaris ha dimostrato di poter produrre mannoproteine diverse, con caratteristiche funzionali legate alla stabilità del vino. Le manoproteine estratte dalle colture di S. bacillaris presentavano un grande potenziale per aumentare la stabilizzazione delle proteine, mentre se venivano prodotte durante la fermentazione sequenziale con S. cerevisiae, aumentavano la stabilizzazione tartarica. Inoltre, in questa tesi, è stato rilevato un contenuto di glutatione molto elevato in cellule S. bacillaris dopo la fermentazione. Pertanto, le fecce ottenute dalle fermentazioni di S. bacillaris possono essere proposte come fonte di glutatione. Nell'ultima parte di questa tesi si intendeva comprendere le determinanti genomiche delle caratteristiche tecnologiche di S. bacillaris descritte nelle precedenti parti. Per questo è stata eseguita la sequenza intero-genoma di due importanti ceppi S. bacillaris. Con i confronti genomici tra i due ceppi di S. bacillaris e tra S. bacillaris, S. cerevisiae e altri lieviti enologici, sono stati identificati e studiati geni specifici e i percorsi metabolici coinvolti in tratti tecnologicamente rilevanti.
4
Schwarzhans, Jan Philipp [Verfasser], Karl [Akademischer Betreuer] Friehs, Jörn [Akademischer Betreuer] Kalinowski, and Lars M. [Akademischer Betreuer] Blank. "Systematic investigation into the clonal variability of the non-conventional yeast Pichia pastoris / Jan Philipp Schwarzhans ; Karl Friehs, Jörn Kalinowski, Lars M. Blank." Bielefeld : Universitätsbibliothek Bielefeld, 2017. http://d-nb.info/1141295571/34.
Full text
5
MATRAXIA, Michele. "Biotechnological innovations in fermentation process of brewing and honey-based beverages industry." Doctoral thesis, Università degli Studi di Palermo, 2022. https://hdl.handle.net/10447/549964.
Full textAbstract:
La ricerca di microrganismi fermentanti in grado di migliorare le proprietà microbiologiche, fisiche, chimiche, sensoriali e organolettiche delle bevande alcoliche fermentate come vino, birra, idromele, sidro, è considerata ad oggi un punto chiave per lo sviluppo del settore.
Negli ultimi anni, l'aumento della domanda al consumo di nuove bevande fermentate ha causato un enorme bisogno di tecnologie di produzione innovative al fine di ottenere diverse tipologie di prodotti caratterizzati da proprietà sensoriali peculiari. Per raggiungere tale obiettivo, l’impiego di nuovi microrganismi, sia fermentanti che non fermentanti, in grado di conferire al prodotto caratteristiche organolettiche peculiari ed uniche, può rappresentare una valida alternativa ai classici ceppi attualmente in commercio. Il settore vitivinicolo-enologico risulta quello in cui la ricerca ha sviluppato conoscenze sufficienti ad applicare nuove specie e nuovi ceppi di lieviti su scala industriale. La ricerca di lieviti non convenzionali applicabili alle bevande alcoliche che nell’Europa meridionale sono considerate secondarie rispetto al vino, ovvero birra, sidro ed idromele, risulta essere ancora poco investigata, essendo scarsi gli studi disponibili sulla fermentazione di queste bevande. In particolare, il settore birrario sta riscoprendo un rinnovato interesse nei confronti di lieviti isolati da matrici territoriali, considerati responsabili del miglioramento e della creazione di bouquet particolari, che consentono di ottenere produzioni legate al territorio e differenziate su un mercato in forte espansione.
Analogamente alla produzione di birra artigianale, la produzione di idromele sta attualmente vivendo un interesse a livello amatoriale e professionale in tutto il mondo. Sebbene non sia una bevanda molto popolare, il suo consumo in Europa è in costante crescita. Anche in questo settore la letteratura scientifica risulta limitata, specialmente in ambito microbiologico, dato che per condurre le fermentazioni alcoliche sono spesso usati ceppi di S. cerevisiae di origine enologica. Diversamente dal mosto d’uva, il mosto-miele risulta carente in fattori nutrizionali che limitano la crescita microbica. Per tale motivo, la ricerca di lieviti appropriati in grado di crescere e fermentare queste matrici risulta essere un punto cruciale per mantenere un elevato standard qualitativo di questa bevanda.
Sulla base di queste premesse, durante il triennio di Dottorato di ricerca è stata condotta uno studio inerente: l’ecologia microbica di matrici zuccherine; l’isolamento, la caratterizzazione genotipica e tecnologica di lieviti, sia Saccharomyces che non-Saccharomyces; la loro applicazione, sia singolarmente che in combinazione, durante le fermentazioni sperimentali di mosto di birra e mosto-miele; la valutazione della cinetica di fermentazione, metaboliti secondari, composti organici volatili ed analisi sensoriale dei prodotti ottenuti.
6
Tan, Mélissa. "Caractérisation et valorisation de la production d’arômes par la levure non-conventionnelle Saprochaete suaveolens : analyse métabolique de souches sauvages et mutantes et application biotechnologique dans le domaine brassicole." Thesis, La Réunion, 2020. http://www.theses.fr/2020LARE0032.
Full textAbstract:
La grande diversité des composés d’arômes naturels produits par les levures est aujourd’hui décrite comme une option particulièrement intéressante du fait des métabolismes variés présents chez ces microorganismes et leur capacité à produire un large panel de composés organiques volatils (COVs). Parmi les levures non Saccharomyces citées dans la littérature, la levure Saprochaete suaveolens (anciennement connue sous le nom de Geotrichum fragrans) se distingue des autres levures aromatiques pour sa haute productivité en COVs tant du point de vue qualitatif que quantitatif. S. suaveolens est notamment très prometteuse pour sa production en esters α-insaturés à haute valeur ajoutée, qui sont rarement retrouvés dans les bouquets aromatiques des souches levuriennes à l’instar du tiglate d’éthyle, et produits industriellement par voie synthétique pour le marché des arômes. Le métabolisme aromatique de S. suaveolens peut ainsi être perçu comme un modèle pour la production de COVs par les levures. Cette étude avait pour objectif de mieux caractériser et de valoriser la production d’arômes par une souche sauvage de S. suaveolens à l’aide de trois approches. La première approche est basée sur l’utilisation des connaissances du métabolisme aromatique de S. suaveolens pour développer une méthode de criblage permettant de sélectionner des souches de levure sauvages productrices de COVs, notamment sous forme d’esters α-insaturés. La seconde approche a consisté à optimiser la production d’arômes chez S. suaveolens en générant et en sélectionnant des mutants surproduisant des esters insaturés par mutagénèse UV. La dernière approche a permis d’évaluer le pouvoir aromatisant de la levure S. suaveolens en condition de fermentation brassicole. Globalement, les résultats de ces travaux ont montré que notre modèle basé sur le métabolisme de S. suaveolens a permis d’isoler de nouvelles souches de levures productrices d’esters α-insaturés à partir d’échantillons prélevés sur les déjections d’animaux sauvages en Afrique du Sud. Par ailleurs, l’approche mutagénique a permis de démontrer la possibilité d’améliorer très significativement la production de COVs chez S. suaveolens grâce à l’inactivation de l’une des enzymes clées de son métabolisme aromatique, à savoir l’enoyl-CoA hydratase. Enfin, des essais de fabrication de bière ont clairement montré que la levure S. suaveolens possède un pouvoir aromatisant particulièrement appréciable dans le cadre de fermentations mixtes de moûts réalisées en condition industrielle en présence de la levure Saccharomyces cerevisiaeThe huge diversity of natural aroma compounds produced by yeast is described as an option particularly interesting because of the various metabolisms occurring in these microorganisms and their ability of producing a large panel of volatile organic compounds (VOCs). Among the non-Saccharomyces yeast cited in the literature, the yeast Saprochaete suaveolens (former known as Geotrichum fragrans) is distinguishable from the others aromatic yeasts for its high productivity in VOCs both from a quantitative and qualitative point of view. S. suaveolens is notably very promising for its production in high valuable α-unsaturated esters such as ethyl tiglate, which are rarely refund in the aromatic bouquet of yeast strains and which are industrially produced by synthetical way for the aroma market. Aromatic metabolism of S. suaveolens could therefore be seen as a modele for VOCs production by yeast. This study aimed at better characterizing and valorizing the aroma production by a wild strain of S. suaveolens by three approaches. First approach is based on the use of the knowledges on aromatic metabolism of S. suaveolens to develop a screening method allowing the selection of natural VOCs producing wild strains, notably under form of α-unsaturated esters. The second approach consisted in optimizing the aroma production by S. suaveolens while generating and selecting mutants overproducing unsaturated esters via UV mutagenesis. The last approach allowed evaluating the aromatization power of S. suaveolens in brewery fermentation condition. Globally, results of these works have shown that our model based on S. suaveolens metabolism allowed isolating news α-unsaturated esters producing strains from samples taken from dejections of wild animals in South-Africa. Moreover, the mutagenic approach allowed demonstrating the possibility of very significantly increasing the overall VOCs production of S. suaveolens thank to the inactivation of a key-enzyme of its aromatic metabolism, namely the enoyl-CoA hydratase. Finally, beer making trials clearly showed that S. suaveolens posseses an aromatizing power particularly appreciable in the context of mixed fermentation of musts carried out in industrial conditions in the presence of the yeast Saccharomyces cerevisiae
7
Lança, Alexandra Sofia Baptista. "Metabolism of non-conventional wine yeasts." Master's thesis, 2017. http://hdl.handle.net/10451/30536.
Full textAbstract:
Tese de mestrado em Microbiologia Aplicada, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2017O vinho é um produto com significado cultural e social desde tempos antigos, estando intimamente ligado à história do ser humano e à economia de alguns países. No entanto, a indústria vínica está a ser afetada pelas alterações climáticas, que têm vindo a tornar a produção de vinho conforme os típicos parâmetros comerciais cada vez mais difícil de atingir, enquanto mantendo parâmetros de qualidade segundo a preferência dos consumidores. Estudos a nível mundial confirmam a tendência de aquecimento a nível global das temperaturas climáticas acima das típicas variações normais experienciadas de ano para ano e que induzem o efeito vintage, pequenas variações na qualidade do vinho e rendimento obtido. A subida constante das temperaturas à escala global modificam o potencial de maturação das vinhas, levando à alteração da composição das uvas que se traduz maioritariamente na modificação do conteúdo em taninos e compostos fenólicos, aumento da maturação e maiores concentrações de açúcares. Maiores subidas de temperaturas apontam para maiores aumentos no teor de açúcares no mosto de uva, que apresenta como principal problema para a indústria vínica maiores teores de álcool nos vinhos após fermentação, assim como uma alteração dos atributos sensoriais e da microbiologia vínicas. Teores de etanol acima dos parâmetros comerciais podem impedir a comercialização dos vinhos produzidos. Os elevados teores de etanol obtidos ao fermentar mostos de elevadas concentrações de açúcares devem-se à elevada capacidade fermentativa e de processamento de açúcares das espécies de leveduras utilizadas como culturas fermentativas, que leva a um elevado rendimento no consumo de açúcar e produção de etanol. Elevadas concentrações de álcool favorecem a ocorrência de fermentações incompletas, levando à decomposição do mosto. Além das altas concentrações de etanol, as elevadas temperaturas podem levar a uma menor acumulação de metabolitos cruciais para o desenvolvimento dos perfis organolépticos vínicos durante o desenvolvimento e crescimento das vinhas. Em adição, a actual utilização generalizada de culturas starter para iniciar a fermentação de vinhos na indústria vínica tem conduzido a uma convergência dos perfis sensoriais dos vinhos, que se apresentam cada vez mais constantes e semelhantes entre si, sendo hoje em dia crucial a introdução de maior variedade aromática na maturação dos sabores de vinho para dar continuidade ao desenvolvimento do mercado e à atracção ao consumidor. A utilização das mesmas estirpes de S. cerevisiae para iniciação de fermentações tem-se vindo a manter graças às vantagens que o profundo conhecimento da fisiologia, ciclo de vida, metabolismo, processos de regulação e genoma consensus destas leveduras confere: o poder de controlar o processo fermentativo sabendo exactamente o que esperar que ocorra durante as diferentes fases do mesmo, assim como um conhecimento prévio do produto que se conseguirá obter, assim como das suas características. Várias abordagens têm sido feitas para tentar diminuir os níveis de etanol nos vinhos, nomeadamente abordagens viticulturais, pré-fermentativas e pós-fermentativas. Porém, para enfrentar este problema, é importante ter como alvo não só cada etapa da produção das uvas e da produção de vinho, como também as abordagens microbiológicas, de entre as quais uma opção bastante em aberto e inexplorada é avaliar leveduras não-convencionais na fermentação de vinho e selecção de estirpes com potencial. As leveduras não-convencionais compreendem uma maior variedade fisiológica que as leveduras Saccharomyces. O seu uso vai além da produção de compostos sensorialmente activos, sendo que têm vindo a ganhar crescente interesse para a produção de vinhos com teores de alcóol mais baixos. O objectivo deste trabalho foi caracterizar o metabolismo de duas estirpes de leveduras não-Saccharomyces seleccionadas, Lachancea thermotolerans e Metschnikowia pulcherrima. Para tal, ambas as estirpes foram sujeitas a crescimento numa matriz de mosto sintético sob duas diferentes concentrações de açúcares, assim como duas concentrações diferentes de azoto (total de quatro condições cruzadas). As cinéticas de crescimento de ambas as estirpes (em todos os meios de cultura testados) foram avaliadas antes de prosseguir com os estudos. A estirpe de L. thermotolerans mostrou um crescimento exponencial típico, tendo-se observado que atingiu taxas de crescimento superiores quando em meio de mosto sintético com concentrações mais elevadas de açúcar. Já a estirpe de M. Pulcherrima mostrou taxas de crescimento substancialmente semelhantes em todos os meios de mosto sintético testados, sendo a taxa de crescimento mais elevada (ainda que muito ligeiramente) em condições de elevado açúcar mas níveis mais baixos de azoto. Amostras das culturas foram colhidas ao longo do decurso do crescimento para fingerprinting das estirpes de forma a confirmar a identidade final das estirpes cultivadas antes de prosseguir para as análises de metaboloma. Foi então conduzida uma análise dos metabolitos em diferentes estágios do crescimento seguindo uma abordagem de untargeted metabolomics (análise metabolómica sem alvo específico) utilizando FTICR-MS (espectrometria de massa Fourier Transform Ion Cyclotron Resonance). Esta técnica de espectrometria de massa é particularmente relevante no estudo de metabolitos graças à sua elevada sensibilidade, precisão (< 1 ppm) e ultra-elevada resolução (superior a 1,000,000). Normalmente, um estudo metabólico é realizado recorrendo a técnicas como a Ressonância Magnética Nuclear (NMR) e Espectrometria de Massa (MS) ou à combinação destas técnicas a processos de separação cromatográficos como a Cromatografia Gasosa (CG) ou Líquida (LC). Contudo, os limites de deteção por NMR são baixos, e apesar da combinação de MS com CG e LC possibilitar a deteção de um elevado número de compostos, os processos cromatográficos demoram muito tempo e normalmente necessitam de vários passos de limpeza do equipamento. Uma solução será então a utilização de Fourier Transform Ion Cyclotron Resonance acoplado a um espectrómetro de massa (FTICR-MS), visto que é um equipamento que não só combina a elevada resolução com a elevada exatidão de massa, como também permite uma rápida e fácil aquisição de resultados. Foram analisadas amostras recolhidas nos tempos correspondendo ao início da fase exponencial de crescimento e à fase estacionária de crescimento de ambas as estirpes seleccionadas. Após processamento dos espectros em programas de software adequado e recorrendo a páginas e ferramentas online, foi possível gerar uma lista de compostos com a respectiva distribuição dos mesmos dentro de todas as amostras analisadas. Através de uma análise PCA, foi testada a capacidade de agrupamento através dos perfis metabólicos das diferentes amostras. O agrupamento das amostras deu-se não só por estirpe, como também por tempo e fracção analisada, tendo ocorrido uma boa separação das diferentes amostras. Os metabolitos relevantes já estudados e que se sabe contribuir para o perfil organoléptico e aroma do vinho foram seleccionados para revelar vias metabólicas específicas e diferenças metabólicas entre as estirpes de leveduras estudadas nas diferentes condições de crescimento testadas. Estas diferenças encontradas como resultado da diferente composição do meio irão contribuir para a produção de novos vinhos no que toca a sabor e aroma. Duas das vias metabólicas mais relevantes encontradas nestas leveduras e que contribuem para o sabor e o aroma dos produtos vínicos foram o metabolismo do ácido alfa-linolénico e o metabolismo de biossíntese de sesquiterpenóides. Vários metabolitos pertencentes a estas duas vias foram identificados e verifica-se que a sua distribuição ao longo das fracções e tempos estudados se altera não só com a estirpe como também com o meio de cultura utilizado (ou seja, com as condições de açúcares e de azoto utilizadas no crescimento das leveduras). Apesar da presença destes compostos em leveduras não-convencionais necessitar de mais estudos, estes microorganismos pouco estudados parecem estar a revelar o seu potencial na indústria vínica. Este trabalho veio validar a criação de perfis metabólicos e a sua utilização para estudos comparativos deste género através da técnica de FTICR-MS aplicada.
Non-conventional yeast species comprehend a wider physiological diversity that the commonly used Saccharomyces yeasts. Their use in wine production goes beyond the production of sensory-active compounds. They have gained interest in the production of wines with increased organoleptic profile and lower alcohol content. This is highly crucial for the wine industry, given the alterations in the grape composition due to climate change. These changes, mainly lower acidity, changes in phenolic and tannin contents, altered maturation, and increased sugar concentration, contribute to increase the alcohol content in wines, modify sensory attributes and wine microbiology. To tackle this problem, it is important to target not only every stage of grape production and winemaking, but also aspects related to microbiological approaches and the selection of non-conventional yeasts for wine fermentation. The goal of this work was to characterize the metabolism of two selected non-Saccharomyces yeasts (Lachancea thermotolerans and Metschnikowia pulcherrima) grown in a synthetic must matrix under different sugar and nitrogen concentrations. Growth was followed for 71 hours, with sample collection at different timepoints. At the end of cell growth, a DNA fingerprinting analysis confirmed the strain’s identity in the culture. Metabolite analysis at different growth stages, in both cells and culture medium, was performed following an untargeted metabolomics approach using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS). Based on the metabolic profiling, the different strains and culture media could be segregated. Relevant metabolites known to contribute to wine flavour and aroma were selected to uncover specific pathways and metabolic differences between the studied yeast strains in the different growth conditions. These differences found so far as a result of the different media compositions will contribute to the production of novel wines, both in flavour and aroma.
8
Lopes, Marlene. "Characterization of non-conventional yeasts under hyperbaric conditions : cellular response to oxidative stress." Doctoral thesis, 2013. http://hdl.handle.net/1822/24789.
Full textAbstract:
Tese de doutoramento em Chemical and Biological EngineeringProviding an adequate oxygen supply is critical to the growth and maintenance of most aerobic microbial cultures used in biotechnological processes. Oxygen mass transfer from gas phase to the culture medium is often a major growth limiting factor because of oxygen´s low solubility in an aqueous solution. Thus, ensuring adequate oxygen supply to submerged cultures in bioreactors is not trivial. The use of increased air pressure as a way of improving oxygen mass transfer from gas phase to liquid phase has been developed by some authors. However, the effect of reactor pressurization must be considered on cellular growth and metabolism. The increase of oxygen partial pressure could result in reactive oxygen species (ROS) formation and lead to an oxidative environment to the cells. As the effect of increased air and oxygen pressure is strongly dependent of the cell type, species and strains, due to their different abilities of cellular response to possible oxidative stress that can arise, this thesis is focused on the study the behavior of non-conventional yeasts under hyperbaric air. In spite of the well-known importance of Yarrowia lipolytica and Pichia pastoris in several biotechnological processes, few studies are available on the application of air pressure increase for the cultivation of these yeasts. This work was started with the study of the oxygen mass transfer phenomenon from gas phase to the medium in a lab-scale pressurized bioreactor. The influence of operation parameters (aeration and stirring rates and increased air pressure up to 5 bar) on oxygen transfer rate (OTR) was analyzed. An empirical correlation for the prediction of the volumetric oxygen mass transfer coefficient (kLa) as a function of air pressure, power input and superficial gas velocity was attempted. The results demonstrated that the increased air pressure is valuable option for OTR enhancement in bioreactors, competing favorable with raising stirring and aeration rates, which can cause cell damage by shear stress. Yeast cells exposed to adverse conditions employ a number of defense mechanisms to respond effectively to the stress effects of reactive oxygen species. The cellular response of Y. lipolytica W29 and P. pastoris CBS 2612 to the exposure to the ROS-inducing agents paraquat (1 mM), hydrogen peroxide (50 mM) and increased air pressure (1 bar and 5 bar) was analyzed. For both strains the cellular viability loss and lipid peroxidation was lower for the cells exposed to increased air pressure than for those exposed to chemical oxidants. Under superoxide stress (paraquat and air pressure), the SOD induction was the main observed mechanism, whereas the hydrogen peroxide was the most efficient inducer of catalase. The results suggested that Y. lipolytica have a more potent antioxidant system than P. pastoris. Batch cultivations of Y. lipolytica W29 under air pressures up to 6 bar were performed to investigate whether increasing air pressure may lead to increasing biomass yields, without giving raise to oxidative stress. The levels of antioxidant enzymes induced were also monitored. Cell growth was strongly enhanced by the pressure raise, since 5- and 3.4-fold improvement in the biomass production and in specific growth rate, respectively, were observed under 6 bar. An increase of the SOD specific activity at 6 bar of 53.4-fold was obtained compared with the experiments under 1 bar. Moreover, the influence of a pre-adaptation phase of cells to hyperbaric conditions on the lipase production by Y. lipolytica cells was investigated. The extracellular lipase activity increased 96% using a 5 bar air pressure instead of air at 1 bar pressure during the enzyme production phase. These results demonstrated that air pressure increase in bioreactors is an effective way for the enhancement of cell mass and enzyme productivity in bioprocesses involving Y. lipolytica cultures. P. pastoris CBS 2612 behavior under air pressures of 1 bar, 3 bar and 5 bar in culture media of glycerol (pure and crude) and methanol was studied. Generally, an enhancement on cellular growth, for all carbon sources, was achieved with the raise of air pressure and for batch and fed-batch processes with different feeding rate strategies. In batch cultures, 1.4-, 1.2-, and 1.5-fold improvement in biomass production was obtained with the increase of air pressure up to 5 bar, using methanol, pure glycerol, and crude glycerol, respectively. The increase of air pressure up to 5 bar using exponential feeding rate led to a 1.4-fold improvement in biomass yield per glycerol mass consumed, for pure and crude glycerol. The results show the possibility of improving cell mass production of P. pastoris under moderate air pressure, using low cost carbon sources. P. pastoris GS115/pPICZ/lacZ (Mut+), expressing intracellular β-galactosidase, and P. pastoris KM71H/pPICZαA/frutalin (MutS), expressing extracellular frutalin, were used to investigate the effect of increased air pressure on yeast growth and heterologous protein expression. The increase of air pressure up to 5 bar had a small effect on biomass production, but led to a 9-fold improvement in β-galactosidase specific activity compared to 1 bar. The recombinant frutalin secretion was enhanced by the increased air pressure up to 5 bar and the protease specific activity reached was 2.4 times lower than that obtained at atmospheric pressure in baffled flasks.
Um dos pontos críticos de processos biotecnológicos consiste no fornecimento de oxigénio suficiente para o crescimento e manutenção das culturas microbianas aeróbias. A velocidade de transferência de oxigénio do gás para o meio de cultura é normalmente um fator limitante do crescimento, devido à baixa solubilidade do oxigénio em soluções aquosas. Assim, garantir o adequado aprovisionamento de oxigénio a culturas submersas num bioreator não é uma tarefa menosprezável. São poucos os investigadores que têm recorrido ao aumento da pressão de ar como forma de melhorar a transferência de oxigénio da fase gasosa para a fase líquida. Neste caso, o efeito da pressurização do reator no crescimento e metabolismo celular deve ser tido em consideração. Além disso, o aumento da pressão parcial do oxigénio pode resultar na formação de espécies reativas de oxigénio e originar um ambiente oxidativo para as células. Uma vez que o efeito do aumento da pressão de ar e de oxigénio depende das espécies e estirpes, devido à diferente capacidade de resposta ao stresse oxidativo, esta tese foca-se no estudo da resposta celular de leveduras não-convencionais ao ar hiperbárico. Apesar da reconhecida importância das espécies Yarrowia lipolytica e Pichia pastoris em muitos processos biotecnológicos, são poucos os estudos sobre a aplicação do aumento da pressão de ar na cultura destas leveduras. Este trabalho começou com o estudo da taxa de transferência de oxigénio da fase gasosa para o meio líquido num reator pressurizado, à escala laboratorial. Foi analisada a influência de parâmetros operacionais (taxa de arejamento e de agitação e aumento da pressão de ar até 5 bar) na taxa de transferência de oxigénio (OTR). Obteve-se uma correlação empírica do coeficiente volumétrico de transferência de oxigénio (kLa) em função da pressão de ar, da potência de agitação e da velocidade superficial do gás. Os resultados demonstraram que o aumento da pressão de ar é uma opção viável para o incremento de OTR nos bioreatores, em alternativa ao aumento da taxa de arejamento e de agitação, que podem causar stresse hidrodinâmico às células. As células de levedura, quando expostas a condições adversas, desenvolvem um sistema de defesa contra os efeitos causados pelas espécies reativas de oxigénio. Assim, foi analisada a resposta celular das estirpes Y. lipolytica W29 e P. pastoris CBS 2612 à exposição aos agentes indutores de espécies reativas de oxigénio paraquat (1 mM), peróxido de hidrogénio (50 mM) e pressão total de ar (1 bar e 5 bar). Em ambas as estirpes, a perda de viabilidade e a peroxidação lipídica foram menores nas células expostas ao aumento da pressão de ar do que nas expostas aos oxidantes químicos. Em ambiente de stresse provocado pelo ião superóxido (paraquat e pressão de ar), o mecanismo de defesa mais observado foi a indução de SOD, enquanto o peróxido de hidrogénio foi o maior indutor da catalase. Os resultados sugerem que a estirpe Y. lipolytica tem um sistema antioxidante mais eficaz que a estirpe P. pastoris. Com o objectivo de investigar se o aumento da pressão de ar podia conduzir a um incremento no rendimento em biomassa, sem originar stresse oxidativo, foram realizados ensaios em modo batch de Y. lipolytica W29 a valores de pressão total de ar até 6 bar. Foi igualmente avaliada a capacidade da levedura em induzir a expressão de enzimas antioxidantes. O crescimento celular foi consideravelmente beneficiado com o aumento da pressão de ar, uma vez que a produção de biomassa e a taxa específica de crescimento aumentaram 5 e 3.4 vezes, respectivamente, no ensaio realizado a 6 bar. A atividade específica da enzima SOD obtida no ensaio a 6 bar foi 53.4 vezes maior do que a alcançada a 1 bar. Foi também analisada a influência de uma fase de pré-adaptação das células às condições hiperbáricas na produção de lipase por Y. lipolytica. A atividade da lipase extracelular aumentou 96% com a aplicação de uma pressão de ar igual a 5 bar, comparativamente ao ensaio realizado a 1 bar, durante a fase de produção da enzima. Estes resultados demonstraram que o aumento da pressão total de ar é uma forma eficaz de aumentar a produtividade em biomassa e em enzima SOD em bioprocessos que utilizem a levedura Y. lipolytica. Foi estudado o comportamento da estirpe P. pastoris CBS 2612 em meios de glicerol (puro e bruto) e metanol, com valores de pressão iguais a 1 bar, 3 bar e 5 bar. De uma maneira geral, foi observado um incremento do crescimento celular com o aumento da pressão de ar, em todas as fontes de carbono e em processos em modo batch e fed-batch com 2 estratégias de alimentação diferentes. Nas culturas em modo batch usando metanol, glicerol puro e glicerol bruto, obtiveram-se aumentos de 1.4, 1.2 e 1.5 vezes, respectivamente, na produção de biomassa com a pressão de 5 bar. No processo fed-batch com alimentação exponencial, o rendimento em biomassa por massa de glicerol consumido (puro e bruto) aumentou 1.4 vezes com o uso de pressão de ar igual a 5 bar. Os resultados demonstram a possibilidade de aumentar a produção de biomassa de P. pastoris sob pressão de ar moderada, usando fontes de carbono de baixo custo. A estirpe P. pastoris GS115/pPICZ/lacZ (Mut+), que expressa β-galactosidase intracelular, e a estirpe KM71H/pPICZαA/frutalina (MutS), que expressa frutalina extracelular, foram usadas com o intuito de estudar o efeito do aumento da pressão de ar no crescimento destas estirpes e na expressão de proteínas heterólogas. O aumento da pressão total de ar até 5 bar não teve um efeito significativo no crescimento celular destas estirpes, mas conduziu a um incremento de 9 vezes na actividade específica da enzima β- galactosidase, comparativamente à obtida a 1 bar. A expressão de frutalina também aumentou a 5 bar e a actividade específica de protease obtida foi 2.4 vezes inferior à obtida nos ensaios em matraz (pressão atmosférica.
9
Troiano, Eleonora. "BIODIVERSITY OF METSCHNIKOWIA PULCHERRIMA AS A RESOURCE FOR INNOVATION IN FERMENTED BEVERAGES." Doctoral thesis, 2022. https://hdl.handle.net/11562/1079946.
Full textAbstract:
The present PhD thesis was developed with the general aim of exploring the diversity and the biotechnology potential of nonconventional yeasts ascribed to the genus Metschnikowia, and in particular to the species M. pulcherrima, for application in winemaking and fermented beverages. Indeed, they could be considered promising bioresources, useful to contribute to innovation and sustainability in the agrifood sector in the framework of the Sustainable Development Goals, specifically SGDs 9 and 12, pertaining to “industry, innovation and infrastructure” and “responsible consumption and production”, respectively. The first part of this thesis was focused on a single strain M. pulcherrima DBT012, previously selected for winemaking, on its taxonomic placement and possible industrialization. Its genome was sequenced, and comparative genomics allowed to support its identification at the species level as well as the very recent reclassification of the entire clade, which was previously formed by 11 species. As for strain industrialization, the protocol for dry biomass production was successful and, as the strain retained high viability during rehydration and showed suitable activity when inoculated in grape must. In the second part of the thesis, the genotypic and phenotypic biodiversity of 193 isolates, gathered from different isolations sources (plants, flowers, fruits, and musts), different countries (Italy and Poland), and in different years (from 2016 to 2020) was explored. The dereplication process allowed the recognition of 129 strains displaying a high genotypic variability as well as significant phenotypic diversity in terms of βglucosidase and esterase activities and H2S production. A subset of the collection, representative of the phenotypic diversity, was chosen for in-depth technological characterization, aimed at selecting 3 strains for labscale fermentation of commercial apple juice. The fermentations were followed by microbiological, chemical, and sensorial analyses of the fermented juices. Remarkably, despite the different enzymatic activities observed in vitro during the screening step, the results of the volatile compounds in the fermented juices did not reveal significant variations of important aromaactive molecules, especially esters, among the three strains. Those discrepancies suggested that in vitro screening procedures were not predictive of strain abilities in a real fermentation matrix; therefore, alternative enzymatic screening procedures should be devised and biocatalytic mechanisms should be further investigated as well. The collection realized in this study will be deposited in the Verona University Culture Collection (VUCCDBT) and, to date, it represents the biggest repository of Metschnikowia pulcherrima yeasts that will be publicly available. Finally, during the PhD, a model system based on yeast resting cells was performed to test for biocatalytic properties of microbial strains. The study was published, and it is reported in the appendix of the thesis.
10
Lagoas, Catarina Marreiros. "A broad evolutionary perspective of alcoholic fermentation in a non-conventional yeast clade." Master's thesis, 2021. http://hdl.handle.net/10362/132847.
Full textAbstract:
The evolution of alcoholic fermentation in the non-conventional Wickerhamiella/Starmerella (W/S)
yeast clade is characterized by the loss of native pyruvate decarboxylase (PDC1) and alcohol
dehydrogenase (ADH) genes. In some species, the reacquisition of this via was achieved through
horizontal gene transfer (HGT) of ADH and co-option of a native decarboxylase, Aro10. This work
aimed to build on the previous knowledge regarding alcoholic fermentation in the W/S clade, by
combining in silico data obtained from newly sequenced genomes, with phenotypic assays, aiming
to assess alcoholic fermentation abilities and characterization of Adh enzymes, in a subset of
species. Three independent HGT events were previously reported to have introduced different
bacterial ADH1 in distinct subgroups of the W/S clade. Subgroups A, B and C harbour ADH1a,
ADH1b and ADH1c, respectively. Subgroup ADH0 does not carry an ADH1. In this work, data
supporting these three HGT events was obtained and two new HGT events of bacterial ADH6 were
detected. Most ADH6 genes were acquired in the ancestor of the subgroups reported for ADH1,
while one was found in a ADH0 species (Wickerhamiella slavikovae) that seemingly lacks other
alcoholic fermentation genes (ADH1, PDC1 and ARO10). As for the remaining species, while
ARO10 is present, PDC1 is absent. Ethanol production was generally observed in subgroup A,
while its assimilation was verified in subgroups B and C, suggesting that Adh proteins are
functional. It was confirmed that Adh1a from Starmerella bombicola is involved in the
interconversion of acetaldehyde and ethanol, using NAD(H) and NADP(H) as cofactors, which
contrasts with the specificity of Adh proteins from yeasts towards NAD(H). To further understand
the evolution of the alcoholic fermentation in the W/S clade, it is essential to combine comparative
genomics with the characterization of these enzymes to evaluate their role on the central carbon
metabolism.A evolução da fermentação alcoólica no clado de leveduras não convencionais Wickerhamiella/Starmerella (W/S) é caracterizada pela perda dos genes nativos da piruvato descarboxilase (PDC1) e das álcool desidrogenases (ADH). Em algumas espécies, a reaquisição desta via foi conseguida através de transferências horizontais de genes (HGT) ADH e pela cooptação de uma descarboxilase nativa, Aro10. Este trabalho teve como objetivo partir do conhecimento prévio relativo à fermentação alcoólica no clado W/S, combinando dados in silico de novos genomas sequenciados, com ensaios fenotípicos, de forma a avaliar as capacidades fermentativas e caracterizar as enzimas Adh, num conjunto de espécies. Três eventos HGT independentes foram previamente identificados como tendo introduzido diferentes ADH1 bacterianos nos distintos subgrupos do clado W/S. Os subgrupos A, B e C possuem ADH1a, ADH1b e ADH1c, respetivamente. O subgrupo ADH0 não possui ADH1. Neste trabalho, dados que suportam estes três eventos HGT foram obtidos e dois novos eventos HGT de ADH6 bacterianos foram detetados. A maioria dos genes ADH6 foram adquiridos nos mesmos ancestrais dos subgrupos reportados para ADH1, enquanto um foi encontrado numa espécie ADH0 (Wickerhamiella slavikovae) que aparentemente não possui outros genes da fermentação alcoólica (ADH1, PDC1 e ARO10). Em relação às espécies restantes, enquanto ARO10 está presente, PDC1 está ausente. A produção de etanol foi geralmente observada no subgrupo A, enquanto a sua assimilação foi verificada nos subgrupos B e C, sugerindo que as proteínas Adh são funcionais. Foi confirmado o papel da Adh1a de Starmerella bombicola na interconversão de acetaldeído e etanol, usando NAD(H) e NADP(H) como cofatores, o que contrasta com a especificidade das proteínas Adh de leveduras relativamente a NAD(H). Para compreender melhor a evolução da fermentação alcoólica no clado W/S, é essencial combinar genómica comparativa com a caracterização destas enzimas, de forma a avaliar o seu papel no metabolismo central de carbono.
Books on the topic "Non conventional yeasts"
1
Wolf, Klaus, Karin Breunig, and Gerold Barth, eds. Non-Conventional Yeasts in Genetics, Biochemistry and Biotechnology. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55758-3.
Full text
2
Sibirny, Andriy, ed. Non-conventional Yeasts: from Basic Research to Application. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21110-3.
Full text
3
1944-, Wolf K., Breunig Karin 1962-, and Barth Gerold, eds. Non-conventional yeasts in genetics, biochemistry and, biotechnology: Practical protocols. Berlin: Springer, 2003.
Find full text
4
Nations, United. The United Nations and the advancement of women, 1945-1996. New York: Dept. of Public Information, United Nations, 1996.
Find full text
5
(Editor), Klaus Wolf, Karin D. Breunig (Editor), and Gerold Barth (Editor), eds. Non-Conventional Yeasts in Genetics, Biochemistry and Biotechnology. Springer, 2003.
Find full text
6
Sibirny, Andriy. Non-Conventional Yeasts: From Basic Research to Application. Springer International Publishing AG, 2020.
Find full text
7
Sibirny, Andriy. Non-Conventional Yeasts: From Basic Research to Application. Springer International Publishing AG, 2019.
Find full text
8
Wolf, Klaus, Gerold Barth, and Karin D. Breunig. Non-Conventional Yeasts in Genetics, Biochemistry and Biotechnology: Practical Protocols. Springer London, Limited, 2012.
Find full text
9
Wolf, Klaus, Gerold Barth, and Karin D. Breunig. Non-Conventional Yeasts in Genetics, Biochemistry and Biotechnology: Practical Protocols. Springer, 2011.
Find full text
10
Mas, Albert, Jose Manuel Guillamón, and Gemma Beltran, eds. Non-conventional Yeast in the Wine Industry. Frontiers Media SA, 2017. http://dx.doi.org/10.3389/978-2-88945-053-4.
Full textBook chapters on the topic "Non conventional yeasts"
1
Rapoport, Alexander. "Anhydrobiosis in Non-conventional Yeasts." In Non-conventional Yeasts: from Basic Research to Application, 341–59. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21110-3_10.
Full text
2
Maekawa, Hiromi, and Douglas R. Drummond. "Microtubules in Non-conventional Yeasts." In Non-conventional Yeasts: from Basic Research to Application, 237–96. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21110-3_8.
Full text
3
Passoth, Volkmar, and Johan Schnürer. "Non-conventional yeasts in antifungal application." In Topics in Current Genetics, 297–329. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-37003-x_10.
Full text
4
Sannino, Ciro, Ambra Mezzasoma, Pietro Buzzini, and Benedetta Turchetti. "Non-conventional Yeasts for Producing Alternative Beers." In Non-conventional Yeasts: from Basic Research to Application, 361–88. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21110-3_11.
Full text
5
Passoth, Volkmar. "Conventional and Non-conventional Yeasts for the Production of Biofuels." In Yeast Diversity in Human Welfare, 385–416. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-2621-8_15.
Full text
6
Simões, João, and Ana Catarina Gomes. "Isolation and Selection of Conventional and Non-Conventional Fermentative Yeasts." In Advances in Food Biotechnology, 243–62. Chichester, UK: John Wiley & Sons Ltd, 2015. http://dx.doi.org/10.1002/9781118864463.ch14.
Full text
7
Stasyk, Olena G., and Oleh V. Stasyk. "Glucose Sensing and Regulation in Yeasts." In Non-conventional Yeasts: from Basic Research to Application, 477–519. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21110-3_14.
Full text
8
Linder, Tomas. "Nitrogen Assimilation Pathways in Budding Yeasts." In Non-conventional Yeasts: from Basic Research to Application, 197–236. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21110-3_7.
Full text
9
Fukuhara, Hiroshi. "Linear and Circular Plasmids of Yeasts." In Non-Conventional Yeasts in Genetics, Biochemistry and Biotechnology, 437–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55758-3_68.
Full text
10
Nel, Sanet, Michel Labuschagne, and Jacobus Albertyn. "Advances in Gene Expression in Non-Conventional Yeasts." In Yeast Biotechnology: Diversity and Applications, 369–403. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-1-4020-8292-4_18.
Full textConference papers on the topic "Non conventional yeasts"
1
Jamai, L., and M. Ettayebi. "Bioethanol production process using the non-conventional yeast Candida tropicalis." In 2013 International Renewable and Sustainable Energy Conference (IRSEC). IEEE, 2013. http://dx.doi.org/10.1109/irsec.2013.6529710.
Full text
2
Armstrong, John A. "Where Conventional Computing Will Be Ten Years From Now." In Optical Bistability. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/obi.1985.tuc2.
Full textAbstract:
This talk will attempt a projection of the capabilities of "conventional" semiconductor - based computing ten years from now. This will provide a context in which to understand the capabilities that optical computing will have to have to establish a foothold in the industry.
3
Riaño Caraza, Juan M., Fernando S. Flores Avila, Iván Faría Rojas, and Luis E. Brito Rodríguez. "Development of a Performance Assessment Model (PAM) for High Complexity Non-Conventional Reservoirs." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-84183.
Full textAbstract:
Chicontepec is one of the areas with the largest volume of original oil in place in Mexico; however, after more than 30 years of operation, its development has been very limited due to the high geological complexity and low rock quality of their reservoirs. The reservoirs are found in layered sequences of sediments deposited in turbiditic environments which have suffered different degrees of diagenesis, there is a great level of vertical heterogeneity and a very limited level of lateral continuity. The permeability of the reservoir area is in the range of 0.1 to 5 md, depending on the location and degree of diagenesis, with this level of permeability most wells require hydraulic fracturing to be produced economically. The volume of oil originally in place according to the latest certifications is around 130 billion barrels, of which to this date have been produced 200 MMbls, which represents a current recovery factor of 0.15%. In order to accelerate the development of reserves PEMEX has diversified efforts assigning some areas to other companies. This will provide greater ability to assess best practices and technologies. To evaluate the efforts of companies a performance assessment model was designed, which takes into account the integral complexity of each area to be fair in comparing the results obtained for the different areas. The aim of this paper is to describe the methodology used in the developing of the performance evaluation and integral complexity characterization models.
4
Dedmon, S. "Going Beyond Conventional Problem Solving for Two Railroad Wheel Defects." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1312.
Full textAbstract:
Conventional problem solving is a time-honored and accepted methodology for solving many problems we encounter in our daily home and work lives. Thought processes can be linear (like a programmer) or non-linear and still use conventional problem solving skills. Conventional problem solving begins with a statement of the problem, accumulation of data, analysis of data and proposals of solutions to the problem, then testing of the hypotheses. Non-conventional problem solving often skips some of these steps, beginning with a statement of the problem and ending with possible solutions. The tools of conventional problem solving include “critical thinking”, Fool-proofing, “thinking outside the box” and Statistical techniques. Consider the first of our ancestors to figure out that harnessing fire would provide security from large predators, make food safer and easier to eat and make tools such as fire hardened tips on spears. Did all these inventions occur in one moment of genius, or did they take innumerable years to accomplish? Sometime in this process of non-conventional thinking our ancestors brought forth a new technology which ensured the survival of our species. So, how does non-conventional problem solving work? When current theory does not appear to work, then we look to the margins of our science to see if current theory continues to be ineffective. Most theories fail in the margins of the science. A classic example of conventional science failing in the margins is the general and special theory of relativity. Non-conventional problem solving offers greater opportunity for revolutionary rather than incremental, or evolutionary advancements to our science. Other examples are included in this paper. Two wheel related problems are also presented using non-conventional problem solving techniques to provide alternative solutions.
5
Andrei, L., A. Andreini, C. Bianchini, and B. Facchini. "Numerical Benchmark of Non-Conventional RANS Turbulence Models for Film and Effusion Cooling." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68794.
Full textAbstract:
In the course of the years several turbulence models specifically developed to improve the predicting capabilities of conventional two-equations RANS models have been proposed. However they have been mainly tested against experiments only comparing with standard isotropic models, in single hole configuration and for very low blowing ratio. A systematic benchmark of the various non-conventional models exploring a wider range of application is hence missing. This paper performs a comparison of 3 recently proposed models over three different test cases of increasing computational complexity. The chosen test matrix covers a wide range of blowing ratios (0.5–3.0)including both single row and multi-row cases for which experimental data of reference are available. In particular the well known test by Sinha and Bogard [1] at BR = 0.5 is used in conjuction with two in-house carried out experiments: a single row film-cooling test at BR = 1.5 and a 15 rows test plate designed to study the interaction between slot and effusion cooling at BR = 3.0. The first two considered models are based on a tensorial definition of the eddy viscosity in which the stream-span position is augmented to overcome the main drawback connected with standard isotropic turbulence models that is the lower lateral spreading of the jet downwards the injection. An anisotropic factor to multiply the off-diagonal position is indeed calculated from an algebraic expression of the turbulent Reynolds number developed by Bergeles [2] from DNS statistics over a flat plate. This correction could be potentially implemented in the framework of any eddy viscosity model. It was chosen to compare the predictions of such modification applied to two among the most common two-equation turbulence models for film-cooling tests, namely the Two-Layer (TL) model and the k–ω Shear Stress Transport (SST), firstly proposed and tested in the past respectively by Azzi and Lakeal [3] and Cottin at al. [4]. The third model, proposed by Holloway et al. [5], involves the unsteady solution of the flow and thermal field to include the short-time response of the stress tensor to rapid strain rates. This model takes advantage of the solution of an additional transport equation for the local effective total stress to trace the strain rate history. The results are presented in terms of adiabatic effectiveness distribution over the plate as well as spanwise averaged profiles.
6
Pritchett, Joseph E. "Spray-on Ceramic Insulation up to 450°C and Encapsulating existing corrosion without sandblast." In SNAME Maritime Convention. SNAME, 2013. http://dx.doi.org/10.5957/smc-2013-p01.
Full textAbstract:
Ceramic compounds have been around for many years, but the research to find which compounds, what size, crystalline structure and density would perform to block “heat load” is the keys the selecting the correct compounds to use. “Blocking heat load from radiation or resisting the absorption and loading of heat when used over a hot surface” is determined by the aspects stated above. None of this could be determined from the ceramic catalogs of listed compounds stating referenced characteristics. To determine how a compound would react in a paint/coating form could only be realized by trial and error when the compound is mixed in a resin solution with other compounds to see the result. This process has taken 23 years and over 3600 compounds to find 12 compounds that will continue to work when wet and mixed with other materials. As to the corrosion encapsulation without the need for sandblasting, this was studied after finding that most all corrosion protection specifications require sandblast, primers and top coats which over time did not perform as theory had projected. Part of the reason is due to the time frame after the blast is performed before the paints are applied. By the time the paints are applied a flash rust or bloom has set up and the surface is now out of specification and the result is a failure of the system. Research was applied on how a corrosion coating could be made to first penetrate deep into the pores of metal or rust, then swell and encapsulate the pores and/or surface rust before it sets up to 6780 psi surface tensile strength. In this way, the surface rust is used as the profile needed to anchor the coating and add to the strength of the coated film.
7
Minav, Tatiana A., Panu Sainio, and Matti Pietola. "Direct-Driven Hydraulic Drive Without Conventional Oil Tank." In ASME/BATH 2014 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fpmc2014-7834.
Full textAbstract:
In the past few years, direct-driven hydraulic drive (DDH) has synthesized the advantages of compact high power of the hydraulic system and flexible control of the electric motor. This paper investigates the direct-driven hydraulic setup for the non-road mobile machinery (NRMM) application. In the proposed setup, the speed and position control of a double-acting cylinder is implemented directly with a Synchronous Torque Motor drive in a close-loop system without conventional control valves and oil tank. In relation to this, hydraulic accumulator is employed as a replacement of the conventional oil tank. For position and speed control of this closed-loop system, only single feedback is applied from motor’s rotor encoder. As a result, excellent control capabilities of a modern electric drive brings along safety functions and monitoring capabilities of the motor and controller to benefit the hydraulic system. Functionalities of motor controllers offer opportunities to duplicate conventional sensors based on either safety or reliability demands. The system is investigated by means of measurements and also simulation models.
8
Elwegaa, Khalid, Oladoyin Kolawole, Saleh Ahmed, and Olusegun Stanley Tomomewo. "A Non-Conventional Well Technology Approach to Improve Hydrocarbon Recovery from a Mature Field: Brown Field Case Study." In SPE Eastern Regional Meeting. SPE, 2022. http://dx.doi.org/10.2118/211881-ms.
Full textAbstract:
Abstract Hydrocarbon recovery from conventional reservoirs is currently at a declining rate, thus, the petroleum industry needs to find ways to economically produce hydrocarbon from mature and marginal oilfields in conventional reservoirs. Non-conventional well technology can enable the oil industry to do so. This study investigated how a novel non-conventional well technology coupled with a geomechanical approach can potentially improve hydrocarbon recovery from mature fields. Here, we utilized data from Brown field XX located in North Africa, and it is composed of distinct geological formations. One of the formations, "Upper Gir," is an ideal candidate for the application of the non-conventional well technology. We used a reservoir simulator (SURE) to create a dynamic model by incorporating geomechanical tools from a static model previously built using Petrel software. SURE was used to model five simulation scenarios, with each scenario featuring a different well type. The scenarios simulated are the base case, do-nothing, vertical wells, horizontal wells, and multi-lateral wells. The model developed in this study forecasted 25 years of oil production for each simulation scenario and analyzed the results. The results of our numerical simulation study revealed that for 25 years, the multilateral wells produced +0.9% and +0.5% more hydrocarbon than the conventional wells and the horizontal wells, respectively. We also observed a reduction in the average water-cut from 25% to 20% (achieved in the conventional-well scenario) and from 23% to 20% (achieved in the horizontal-well scenario). Our proposed non-conventional well technology has shown promising potentials to improve hydrocarbon recovery, stabilize reservoir pressure, economic returns, and eliminate the risk of water conning in mature fields.
9
Wei, Y., U. Nienhuis, and E. Moredo. "Two Approaches to Scheduling Outfitting Processes in Shipbuilding." In SNAME Maritime Convention. SNAME, 2009. http://dx.doi.org/10.5957/smc-2009-p09.
Full textAbstract:
In shipbuilding, outfitting is the process of installing non-structural components, like equipment, pipes, cables, ducts, etc., which can run through several structural compartments. Pre-outfitting is defined as outfitting activities that take place before hull erection, thus during panel, section and block assembly. The outfitting process is characterized by interferences between yard and many subcontractors, disturbances by unexpected delays, and technological constraints concerning the installation of main propulsion machinery. Scheduling of this process is therefore quite complex and a difficult topic to research. According to extensive literature study, there have been some relevant paper published more than twenty years ago[1],[2],[3],although since then the topic has not received much attention.. Traditionally, the initial outfitting process planning is generated largely manually by experts with the help of computer software, like Microsoft Project and Primavera. These tools allow some limited plan checking and evaluation. As soon as special simulation tools, for example based on eM-Plant or, Arena, are fully developed, plans can be tested, analyzed and optimized in a more accurate way. Even though the digitalization of downstream work is being developed, the initial plan depends greatly on experts. They have to be trained and then gain their expertise from practice. It generally takes over five years for someone to acquire sufficient expertise in a particular area[4]. Furthermore, the knowledge the experts gained by their years of experience may be lost, due to retirement and personnel quitting the company. Hence, it is indispensable to make such tacit knowledge explicit through models. It means that in order to optimize the facilities, maximize the production efficiency and minimize the building time, it is necessary to develop a system to automatically generate plans for outfitting processes, which can also support the simulation models afterwards for verification purposes. The research discussed in this paper looks into the possibilities to automatically generate an outfitting sequence and planning, based on two approaches. The first approach is an analytical approach, where the focus lies on the most convenient installation sequence on a system or compartment level. This sequence considers all relations between activities within one system and with activities of other systems, and relations within one compartment and its adjacent compartments. Then a mathematical approach is discussed. Physical constraints between the pipes, ducts, cable trays, etc. are introduced and represented. A model is made to generate an installation sequence of these components in one compartment.
10
Cook, G., D. C. Jones, K. D. Ridley, and A. M. Scott. "Atmospheric Compensation using non-linear optical phase conjugation." In Adaptive Optics. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/adop.1995.thb3.
Full textAbstract:
Conventional adaptive optics have been developed over many years for the purpose of imaging and for directing laser beams through atmospheric turbulence. In this application light from a known point source is collected and a mirror or phase shifting array is modified until the collected light can be focused to form a point image. When this goal is achieved then a collimated laser beam can be directed back through the optical system and will retrace the path of the incident light back to the source. The limitations of conventional adaptive optics are determined by the time taken to measure the wave-front and move actuators, the number of actuators available and hence the degree of compensation which can be achieved, and the degree of computation required to get effective compensation.
Reports on the topic "Non conventional yeasts"
1
Paternesi Meloni, Walter, Davide Romaniello, and Antonella Stirati. On the Non-Inflationary effects of Long-Term Unemployment Reductions. Institute for New Economic Thinking Working Paper Series, April 2021. http://dx.doi.org/10.36687/inetwp156.
Full textAbstract:
The paper critically examines the New Keynesian explanation of hysteresis based on the role of long-term unemployment. We first examine its analytical foundations, according to which rehiring long-term unemployed individuals would not be possible without accelerating inflation. Then we empirically assess its validity along two lines of inquiry. First, we investigate the reversibility of long-term unemployment. Then we focus on episodes of sustained long-term unemployment reductions to check for inflationary effects. Specifically, in a panel of 25 OECD countries (from 1983 to 2016), we verify by means of local projections whether they are associated with inflationary pressures in a subsequent five-year window. Two main results emerge: i) the evolution of the long-term unemployment rate is almost completely synchronous with the dynamics of the total unemployment rate, both during downswings and upswings; ii) we do not find indications of accelerating or persistently higher inflation during and after episodes of strong declines in the long-term unemployment rate, even when they occur in country-years in which the actual unemployment rate was estimated to be below a conventionally estimated Non-Accelerating Inflation Rate of Unemployment (NAIRU). Our results call into question the role of long-term unemployment in causing hysteresis and provide support to policy implications that are at variance with the conventional wisdom that regards the NAIRU as an inflationary barrier.
2
Kulshreshtha, Poorvi, Osama Neyaz, Shahina Begum, Raj Kumar Yadav, and Kishore Kumar Deepak. Assessment of the efficacy and safety of the hyperbaric oxygen therapy on pain in patients with fibromyalgia: A systematic review and meta-analysis protocol. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, October 2022. http://dx.doi.org/10.37766/inplasy2022.10.0001.
Full textAbstract:
Review question / Objective: A few studies have addressed the efficacy of hyperbaric oxygen therapy in patients with fibromyalgia. However, these studies have been inconclusive so far. There is no graded evidence in the form of a systematic review or meta-analysis concerning the administration of hyperbaric oxygen therapy to patients with fibromyalgia. The proposed study would be carried out to assess the efficacy and safety of hyperbaric oxygen therapy in reducing pain in patients with fibromyalgia. Primary Objective: To compare the efficacy of HBOT with the standard conventional therapy in patients with fibromyalgia of age 18 years and more. Secondary Objectives: i. To compare the adverse effects (for safety) of HBOT with the standard conventional therapy in patients with fibromyalgia of age 18 years and more; ii. To compare the change in the quality of life, sleep quality, functional impairment, depression, anxiety, and psychological distress by HBOT as compared with the standard conventional therapy in patients with fibromyalgia of age 18 years and more.
3
Valente Rosa, Maria João. Demographic ageing: the rigidity of conventional metrics and the need for their revision. IPR-NOVA, January 2022. http://dx.doi.org/10.23906/wp63/2022.
Full textAbstract:
This article aims to discuss the scope and value of the conventional metrics used to assess and compare levels of ageing between different populations. The age brackets for classifying if the population is ageing or aged are typically based on chronological age and are very close to the stages of the economic tripartite life cycle: the school/education phase; the labour market participation phase; the retirement phase. Those conventional metrics produce distortions in capturing the levels of demographic ageing. If the change in the age structure is rooted in social development, not in a social crisis, having more people in older ages should be related to that. Living longer, on average, does not only mean living more years but also a change in people's social profile, which the usual metrics for measuring ageing do not capture. Because of the central place that demographic ageing occupies in the framework of social, political and scientific reflection on the present and future of societies, Demographic Science should contribute with new metrics reflecting the real social improvements in populations age structures. This reflection supports the need to undertake a critical analysis of the way demographic ageing has usually been presented; stresses the need to advance ageing metrics that match societies' development by considering the life expectancy; and presents a new indicator for measurement demographic ageing that compares what we observe with what we can expect from the age structure at any given mortality level.
4
Nair, Abhijit, and Hamed Humayid Mohammed Al Aamri. Enhanced recovery after surgery pathways for patients undergoing laparoscopic appendectomy- a systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, August 2022. http://dx.doi.org/10.37766/inplasy2022.8.0005.
Full textAbstract:
Review question / Objective: Does implementing enhanced recovery after surgery pathways improve outcomes in adult patients undergoing laparoscopic appendectomy when compared to conventional pathways? Condition being studied: Adult patients (more than 18 years) with acute appendicitis undergoing laparoscopic appendicectomy. Information sources: We will search all electronic databases. In published articles were outcome details appear incomplete, the corresponding author will be contacted the details will be sought. If not available, that outcome will be excluded from analysis.
5
Li, wanlin, jie Yun, siying He, ziqi Zhou, and ling He. Effect of different exercise therapies on fatigue in maintenance hemodialysis patients:A Bayesian Network Meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, November 2022. http://dx.doi.org/10.37766/inplasy2022.11.0144.
Full textAbstract:
Review question / Objective: Population: maintenance hemodialysis patients. Intervention: exercise therapy (resistance exercise； aerobic exercise； resistance combined aerobic exercise； muscle relaxation training； Baduanjin ). Comparison: simple routine nursing. Outcome: fatigue； sleep quality. Study design: randomized controlled trial. Eligibility criteria: Inclusion and exclusion criteria： RCT of study type exercise intervention in MHD patients' fatigue； Study subjects： MHD patients ≥18 years old, regardless of gender, nationality or race； The intervention measures were exercise therapy, including resistance exercise, aerobic exercise, resistance combined aerobic exercise, Baduanjin, muscle relaxation training, etc. The control group was conventional nursing measures or the comparison of the above exercise therapy； Outcome indicators： The primary outcome indicator was fatigue score, and the secondary outcome indicator was sleep quality score； Exclusion criteria： Literature using non-exercise intervention; Non-Chinese and English documents; Unable to obtain the full text or repeated publication of literature; The data cannot be extracted or the extraction is incomplete; There are serious defects in the design of the research experiment.
6
Mort, A. Controls on the distribution and composition of gas and condensate in the Montney resource play. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329790.
Full textAbstract:
The Montney resource play has evolved from a peripheral conventional play to one of the most important hydrocarbon-producing unconventional resource plays in North America and has remained resilient throughout the economic challenges of recent years. Despite maturing as a resource play as a result of more than 15 years of unconventional development and research there are still aspects of the play that are not fully de-risked and prediction of fluid quality remains haphazard due to the complex interplay of geological and engineering factors. Among these are the delineation of structural and stratigraphic barriers and conduits, identification of enigmatic source rocks, which defy traditional methods, evaluating effects of fluid migration and the difficulty in predicting phase behavior in a tight, but open system. This study uses a combined approach leveraging geochemical tools combined with spatial and stratigraphic analysis in an attempt to improve current understanding of these issues.
7
Clausen, Jay, D. Moore, L. Cain, and K. Malinowski. VI preferential pathways : rule or exception. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41305.
Full textAbstract:
Trichloroethylene (TCE) releases from leaks and spills next to a large government building occurred over several decades with the most recent event occurring 20 years ago. In response to a perceived conventional vapor intrusion (VI) issue a sub-slab depressurization system (SSDS) was installed 6 years ago. The SSDS is operating within design limits and has achieved building TCE vapor concentration reductions. However, subsequent periodic TCE vapor spikes based on daily HAPSITE™ measurements indicate additional source(s). Two rounds of smoke tests conducted in 2017 and 2018 involved introduction of smoke into a sanitary sewer and storm drain manholes located on effluent lines coming from the building until smoke was observed exiting system vents on the roof. Smoke testing revealed many leaks in both the storm sewer and sanitary sewer systems within the building. Sleuthing of the VI source term using a portable HAPSITE™ indicate elevated vapor TCE levels correspond with observed smoke emanation from utility lines. In some instances, smoke odors were perceived but no leak or suspect pipe was identified suggesting the odor originates from an unidentified pipe located behind or enclosed in a wall. Sleuthing activities also found building roof materials explain some of the elevated TCE levels on the 2nd floor. A relationship was found between TCE concentrations in the roof truss area, plenum space above 2nd floor offices, and breathing zone of 2nd floor offices. Installation of an external blower in the roof truss space has greatly reduced TCE levels in the plenum and office spaces. Preferential VI pathways and unexpected source terms may be overlooked mechanisms as compared to conventional VI.
8
Morrison, Mark, Joshuah Miron, Edward A. Bayer, and Raphael Lamed. Molecular Analysis of Cellulosome Organization in Ruminococcus Albus and Fibrobacter Intestinalis for Optimization of Fiber Digestibility in Ruminants. United States Department of Agriculture, March 2004. http://dx.doi.org/10.32747/2004.7586475.bard.
Full textAbstract:
Improving plant cell wall (fiber) degradation remains one of the highest priority research goals for all ruminant enterprises dependent on forages, hay, silage, or other fibrous byproducts as energy sources, because it governs the provision of energy-yielding nutrients to the host animal. Although the predominant species of microbes responsible for ruminal fiber degradation are culturable, the enzymology and genetics underpinning the process are poorly defined. In that context, there were two broad objectives for this proposal. The first objective was to identify the key cellulosomal components in Ruminococcus albus and to characterize their structural features as well as regulation of their expression, in response to polysaccharides and (or) P AA/PPA. The second objective was to evaluate the similarities in the structure and architecture of cellulosomal components between R. albus and other ruminal and non-ruminal cellulolytic bacteria. The cooperation among the investigators resulted in the identification of two glycoside hydrolases rate-limiting to cellulose degradation by Ruminococcus albus (Cel48A and CeI9B) and our demonstration that these enzymes possess a novel modular architecture specific to this bacterium (Devillard et al. 2004). We have now shown that the novel X-domains in Cel48A and Cel9B represent a new type of carbohydrate binding module, and the enzymes are not part of a ceiluiosome-like complex (CBM37, Xu et al. 2004). Both Cel48A and Cel9B are conditionally expressed in response to P AA/PPA, explaining why cellulose degradation in this bacterium is affected by the availability of these compounds, but additional studies have shown for the first time that neither PAA nor PPA influence xylan degradation by R. albus (Reveneau et al. 2003). Additionally, the R. albus genome sequencing project, led by the PI. Morrison, has supported our identification of many dockerin containing proteins. However, the identification of gene(s) encoding a scaffoldin has been more elusive, and recombinant proteins encoding candidate cohesin modules are now being used in Israel to verify the existence of dockerin-cohesin interactions and cellulosome production by R. albus. The Israeli partners have also conducted virtually all of the studies specific to the second Objective of the proposal. Comparative blotting studies have been conducted using specific antibodies prepare against purified recombinant cohesins and X-domains, derived from cellulosomal scaffoldins of R. flavefaciens 17, a Clostridium thermocellum mutant-preabsorbed antibody preparation, or against CbpC (fimbrial protein) of R. albus 8. The data also suggest that additional cellulolytic bacteria including Fibrobacter succinogenes S85, F. intestinalis DR7 and Butyrivibrio fibrisolvens Dl may also employ cellulosomal modules similar to those of R. flavefaciens 17. Collectively, our work during the grant period has shown that R. albus and other ruminal bacteria employ several novel mechanisms for their adhesion to plant surfaces, and produce both cellulosomal and non-cellulosomal forms of glycoside hydrolases underpinning plant fiber degradation. These improvements in our mechanistic understanding of bacterial adhesion and enzyme regulation now offers the potential to: i) optimize ruminal and hindgut conditions by dietary additives to maximize fiber degradation (e.g. by the addition of select enzymes or PAA/PPA); ii) identify plant-borne influences on adhesion and fiber-degradation, which might be overcome (or improved) by conventional breeding or transgenic plant technologies and; iii) engineer or select microbes with improved adhesion capabilities, cellulosome assembly and fiber degradation. The potential benefits associated with this research proposal are likely to be realized in the medium term (5-10 years).
9
Putriastuti, Massita Ayu Cindy, Vivi Fitriyanti, and Muhammad Razin Abdullah. Leveraging the Potential of Crowdfunding for Financing Renewable Energy. Purnomo Yusgiantoro Center, June 2021. http://dx.doi.org/10.33116/br.002.
Full textAbstract:
• Renewable energy (RE) projects in Indonesia usually have IRR between 10% and 15% and PP around 6 to 30 years • Attractive return usually could be found in large scale RE projects, although there are numerous other factors involved including technology developments, capacity scale, power purchasing price agreements, project locations, as well as interest rates and applied incentives. • Crowdfunding (CF) has big potential to contribute to the financing of RE projects especially financing small scale RE projects. • P2P lending usually targeted short-term loans with high interest rates. Therefore, it cannot be employed as an alternative financing for RE projects in Indonesia. • Three types of CF that can be employed as an alternative for RE project funding in Indonesia. Namely, securities, reward, and donation-based CF. In addition, hybrid models such as securities-reward and reward-donation could also be explored according to the project profitability. • Several benefits offer by securities crowdfunding (SCF) compared to conventional banking and P2P lending, as follows: (1) issuer do not need to pledge assets as collateral; (2) do not require to pay instalment each month; (3) issuer share risks with investors with no obligation to cover the investor’s loss; (4) applicable for micro, small, medium, enterprises (MSMEs) with no complex requirements; and (5) there is possibility to attract investors with bring specific value. • Several challenges that need to be tackled such as the uncertainty of RE regulations; (1) issuer’s inability in managing the system and business; (2) the absence of third parties in bridging between CF platform and potential issuer from RE project owner; (3) the lack of financial literacy of the potential funders; and (4) lastly the inadequacy of study regarding potential funders in escalating the RE utilisation in Indonesia.
10
Wakefield, Benjamin. Opportunities for the European Union to Strengthen Biosecurity in Africa. Stockholm International Peace Research Institute, November 2022. http://dx.doi.org/10.55163/hbpq5439.
Full textAbstract:
The European Union (EU) has a long history of commitment to improving biological security and supporting multilateral approaches to arms controls and non-proliferation. It has supported various biosecurity programmes in recent years and continues to increase its financial support towards these, with a focus on the universalization of the Biological and Toxins Weapons Convention and United Nations Security Council Resolution 1540. More recently, through Council Decision 2021/2072/ CFSP, the EU has committed even further to strengthening biosafety and biosecurity capabilities in Africa, with more meaningful collaboration and an increase in the local and regional ownership of projects. This provides an opportunity for the EU to continue to broaden its approach and improve coordination with international partners. In particular focus is the newly formed European Health Emergency Preparedness and Response Authority (HERA), as it develops its international activities. However, there is still a demonstrated need to strengthen biosecurity-related capacities and capabilities across Africa. This paper highlights the significant opportunities for EU engagement and coordination with international initiatives, such as the Africa Centres for Disease Control and Prevention (Africa CDC) Biosafety and Biosecurity Initiative (BBI) 2021–2025 Strategic Plan and the Global Partnership Signature Initiative to Mitigate Biological Threats in Africa.