Journal articles: 'Mixed culture fermentations'

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Sieuwerts, Sander, Douwe Molenaar, Sacha A. F. T. van Hijum, Marke Beerthuyzen, Marc J. A. Stevens, Patrick W. M. Janssen, Colin J. Ingham, Frank A. M. de Bok, Willem M. de Vos, and Johan E. T. van Hylckama Vlieg. "Mixed-Culture Transcriptome Analysis Reveals the Molecular Basis of Mixed-Culture Growth in Streptococcus thermophilus and Lactobacillus bulgaricus." Applied and Environmental Microbiology 76, no. 23 (October 1, 2010): 7775–84. http://dx.doi.org/10.1128/aem.01122-10.

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ABSTRACT Many food fermentations are performed using mixed cultures of lactic acid bacteria. Interactions between strains are of key importance for the performance of these fermentations. Yogurt fermentation by Streptococcus thermophilus and Lactobacillus bulgaricus (basonym, Lactobacillus delbrueckii subsp. bulgaricus) is one of the best-described mixed-culture fermentations. These species are believed to stimulate each other's growth by the exchange of metabolites such as folic acid and carbon dioxide. Recently, postgenomic studies revealed that an upregulation of biosynthesis pathways for nucleotides and sulfur-containing amino acids is part of the global physiological response to mixed-culture growth in S. thermophilus, but an in-depth molecular analysis of mixed-culture growth of both strains remains to be established. We report here the application of mixed-culture transcriptome profiling and a systematic analysis of the effect of interaction-related compounds on growth, which allowed us to unravel the molecular responses associated with batch mixed-culture growth in milk of S. thermophilus CNRZ1066 and L. bulgaricus ATCC BAA-365. The results indicate that interactions between these bacteria are primarily related to purine, amino acid, and long-chain fatty acid metabolism. The results support a model in which formic acid, folic acid, and fatty acids are provided by S. thermophilus. Proteolysis by L. bulgaricus supplies both strains with amino acids but is insufficient to meet the biosynthetic demands for sulfur and branched-chain amino acids, as becomes clear from the upregulation of genes associated with these amino acids in mixed culture. Moreover, genes involved in iron uptake in S. thermophilus are affected by mixed-culture growth, and genes coding for exopolysaccharide production were upregulated in both organisms in mixed culture compared to monocultures. The confirmation of previously identified responses in S. thermophilus using a different strain combination demonstrates their generic value. In addition, the postgenomic analysis of the responses of L. bulgaricus to mixed-culture growth allows a deeper understanding of the ecology and interactions of this important industrial food fermentation process.

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Freer, S. N., and R. E. Wing. "Fermentation of cellodextrins to ethanol using mixed-culture fermentations." Biotechnology and Bioengineering 27, no. 7 (July 1985): 1085–88. http://dx.doi.org/10.1002/bit.260270726.

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Alberico, Grazia, Angela Capece, Gianluigi Mauriello, Rocchina Pietrafesa, Gabriella Siesto, Teresa Garde-Cerdán, Diamante Maresca, Raffaele Romano, and Patrizia Romano. "Influence of Microencapsulation on Fermentative Behavior of Hanseniaspora osmophila in Wine Mixed Starter Fermentation." Fermentation 7, no. 3 (July 13, 2021): 112. http://dx.doi.org/10.3390/fermentation7030112.

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In recent years, as a consequence of the re-evaluation of the role of non-Saccharomyces yeasts, several studies have been conducted on the use of controlled mixed fermentations with Saccharomyces and different non-Saccharomyces yeast species from the winemaking environment. To benefit from the metabolic particularities of some non-Saccharomyces yeasts, the management of a non-Saccharomyces strain in mixed fermentation is a crucial step, in particular the use of procedures addressed to increase the persistence of non-Saccharomyces strains during the fermentative process. The use of microencapsulation for cell immobilization might represent a strategy for enhancing the competitiveness of non-Saccharomyces yeasts during mixed fermentation. This study was aimed to assess the fermentative performance of a mixed starter culture, composed by a wild Hanseniaspora osmophila strain (ND1) and a commercial Saccharomyces cerevisiae strain (EC1118). For this purpose, free and microencapsulated cells of ND1 strain were tested in co-culture with EC1118 during mixed fermentations in order to evaluate the effect of the microencapsulation on fermentative behavior of mixed starter and final wine composition. The data have shown that H. osmophila cell formulation affects the persistence of both ND1 and EC1118 strains during fermentations and microencapsulation resulted in a suitable system to increase the fermentative efficiency of ND1 strain during mixed starter fermentation.

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de Bok, Frank A. M., Patrick W. M. Janssen, Jumamurat R. Bayjanov, Sander Sieuwerts, Arjen Lommen, Johan E. T. van Hylckama Vlieg, and Douwe Molenaar. "Volatile Compound Fingerprinting of Mixed-Culture Fermentations." Applied and Environmental Microbiology 77, no. 17 (July 8, 2011): 6233–39. http://dx.doi.org/10.1128/aem.00352-11.

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ABSTRACTWith the advent of the -omics era, classical technology platforms, such as hyphenated mass spectrometry, are currently undergoing a transformation toward high-throughput application. These novel platforms yield highly detailed metabolite profiles in large numbers of samples. Such profiles can be used as fingerprints for the accurate identification and classification of samples as well as for the study of effects of experimental conditions on the concentrations of specific metabolites. Challenges for the application of these methods lie in the acquisition of high-quality data, data normalization, and data mining. Here, a high-throughput fingerprinting approach based on analysis of headspace volatiles using ultrafast gas chromatography coupled to time of flight mass spectrometry (ultrafast GC/TOF-MS) was developed and evaluated for classification and screening purposes in food fermentation. GC-MS mass spectra of headspace samples of milk fermented by different mixed cultures of lactic acid bacteria (LAB) were collected and preprocessed in MetAlign, a dedicated software package for the preprocessing and comparison of liquid chromatography (LC)-MS and GC-MS data. The Random Forest algorithm was used to detect mass peaks that discriminated combinations of species or strains used in fermentations. Many of these mass peaks originated from key flavor compounds, indicating that the presence or absence of individual strains or combinations of strains significantly influenced the concentrations of these components. We demonstrate that the approach can be used for purposes like the selection of strains from collections based on flavor characteristics and the screening of (mixed) cultures for the presence or absence of strains. In addition, we show that strain-specific flavor characteristics can be traced back to genetic markers when comparative genome hybridization (CGH) data are available.

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Antonov, E., I. Schlembach, E. Herweg, L. Regestein, J. Büchs, and M. A. Agler-Rosenbaum. "Method Development for Cellulosic Mixed-Culture Fermentations." Chemie Ingenieur Technik 86, no. 9 (August 28, 2014): 1498. http://dx.doi.org/10.1002/cite.201450145.

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Canonico, Laura, Edoardo Galli, Enrico Ciani, Francesca Comitini, and Maurizio Ciani. "Exploitation of Three Non-Conventional Yeast Species in the Brewing Process." Microorganisms 7, no. 1 (January 8, 2019): 11. http://dx.doi.org/10.3390/microorganisms7010011.

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Consumers require high-quality beers with specific enhanced flavor profiles and non-conventional yeasts could represent a large source of bioflavoring diversity to obtain new beer styles. In this work, we investigated the use of three different non-conventional yeasts belonging to Lachancea thermotolerans, Wickerhamomyces anomalus, and Zygotorulaspora florentina species in pure and mixed fermentation with the Saccharomyces cerevisiae commercial starter US-05. All three non-conventional yeasts were competitive in co-cultures with the S. cerevisiae, and they dominated fermentations with 1:20 ratio (S. cerevisiae/non-conventional yeasts ratios). Pure non-conventional yeasts and co-cultures affected significantly the beer aroma. A general reduction in acetaldehyde content in all mixed fermentations was found. L. thermotolerans and Z. florentina in mixed and W. anomalus in pure cultures increased higher alcohols. L. thermotolerans led to a large reduction in pH value, producing, in pure culture, a large amount of lactic acid (1.83 g/L) while showing an enhancement of ethyl butyrate and ethyl acetate in all pure and mixed fermentations. W. anomalus decreased the main aroma compounds in comparison with the S. cerevisiae but showed a significant increase in ethyl butyrate and ethyl acetate. Beers produced with Z. florentina were characterized by an increase in the isoamyl acetate and α-terpineol content.

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Nout, M. J. R. "Fungal interactions in food fermentations." Canadian Journal of Botany 73, S1 (December 31, 1995): 1291–300. http://dx.doi.org/10.1139/b95-390.

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Fermented foods are of importance worldwide. Most are prepared under nonsterile conditions using mixed cultures, either deliberately or unavoidably. Fungal mixed cultures show interactive relations at various levels. In this paper, inhibitory effects among fungi owing to competition, formation of organic acids, toxic proteins, and mycotoxins are discussed. In addition, fungi show inhibitory effects towards bacteria and vice versa, through pH changes, and excretion of organic acids, antibiotics, peptides, etc. Stimulatory interactions among fungi and between fungi and bacteria relate mainly to carbon and nitrogen metabolism, and they play an important role in the inherent stability of mixed-culture systems maintained by enrichment techniques. Better understanding of natural mixed-culture fermentations has evolved into the development of the concept of cocultivation employing compatible microbial strains of complementary metabolic ability. Especially in the area of direct conversion of complex carbohydrates (e.g., starch, inulin, or lignocellulosic matter into ethanol), cocultivation has much to offer. Genetic modification of starter organisms offers opportunities to improve, for example, their ability to degrade substrate with a minimum of catabolite repression, and produce final products of superior quality. This is illustrated by recent recombinant DNA constructs for alcoholic fermentations. Key words: food, fungi, interaction, inhibition, stimulation, cocultivation.

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Wu, Qun, Jie Ling, and Yan Xu. "Starter Culture Selection for Making Chinese Sesame-Flavored Liquor Based on Microbial Metabolic Activity in Mixed-Culture Fermentation." Applied and Environmental Microbiology 80, no. 14 (May 9, 2014): 4450–59. http://dx.doi.org/10.1128/aem.00905-14.

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ABSTRACTSelection of a starter culture with excellent viability and metabolic activity is important for inoculated fermentation of traditional food. To obtain a suitable starter culture for making Chinese sesame-flavored liquor, the yeast and bacterium community structures were investigated during spontaneous and solid-state fermentations of this type of liquor. Five dominant species in spontaneous fermentation were identified:Saccharomyces cerevisiae,Pichia membranaefaciens,Issatchenkia orientalis,Bacillus licheniformis, andBacillus amyloliquefaciens. The metabolic activity of each species in mixed and inoculated fermentations of liquor was investigated in 14 different cocultures that used different combinations of these species. The relationships between the microbial species and volatile metabolites were analyzed by partial least-squares (PLS) regression analysis. We found thatS. cerevisiaewas positively correlated to nonanal, andB. licheniformiswas positively associated with 2,3-butanediol, isobutyric acid, guaiacol, and 4-vinyl guaiacol, whileI. orientaliswas positively correlated to butyric acid, isovaleric acid, hexanoic acid, and 2,3-butanediol. These three species are excellent flavor producers for Chinese liquor. AlthoughP. membranaefaciensandB. amyloliquefacienswere not efficient flavor producers, the addition of them alleviated competition among the other three species and altered their growth rates and flavor production. As a result, the coculture of all five dominant species produced the largest amount of flavor compounds. The result indicates that flavor producers and microbial interaction regulators are important for inoculated fermentation of Chinese sesame-flavored liquor.

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FIELDS, M. L., A. AL-SHOSHAN, and Y. POOSIRI. "Mixed Culture Fermentations To Improve Nutritional Value of Corn Meal1." Journal of Food Protection 51, no. 11 (November 1, 1988): 866–68. http://dx.doi.org/10.4315/0362-028x-51.11.866.

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One-step fermentation involving two microorganisms inoculated at the same time and two-step fermentations involving two inoculations of different microbes at different times were used to enrich corn meal. Starch in corn meal was first hydrolyzed by amylases of B. stearothermophilus, E. fibuligera or A. oryzae followed by the growth of C. utilis. The combination of E. fibuligera and C. utilis produced a significant (P<0.05) increase in lysine, methionine, tryptophan. The relative nutritive value (%), which reflected the amino acid balance, increased significantly (P<0.05) with this sequence of microorganisms. Niacin, riboflavin, and thiamin increased significantly (P<0.05) when mixed cultures of A. oryzae and E. fibuligera in combination with C. utilis were employed. When E. fibuligera alone was grown, no significant change was observed in thiamin content but significant increases occurred in niacin and riboflavin. A. oryzae by itself produced significant (P<0.05) changes in niacin, riboflavin and thiamin.

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Frantzen, Cyril Alexander, and Helge Holo. "Unprecedented Diversity of Lactococcal Group 936 Bacteriophages Revealed by Amplicon Sequencing of the Portal Protein Gene." Viruses 11, no. 5 (May 16, 2019): 443. http://dx.doi.org/10.3390/v11050443.

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Lactococcus lactis is one of the most important bacteria in dairy fermentations, being used in the production of cheese and buttermilk. The processes are vulnerable to phage attacks, and undefined mixtures of lactococcal strains are often used to reduce the risk of bacteriophage caused fermentation failure. Other preventive measures include culture rotation to prevent phage build-up and phage monitoring. Phage diversity, rather than quantity, is the largest threat to fermentations using undefined mixed starter cultures. We have developed a method for culture independent diversity analysis of lytic bacteriophages of the 936 group, the phages most commonly found in dairies. Using, as a target, a highly variable region of the portal protein gene, we demonstrate an unprecedented diversity and the presence of new 936 phages in samples taken from cheese production. The method should be useful to the dairy industry and starter culture manufacturers in their efforts to reduce phage problems.

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Rodríguez, Jorge, Robbert Kleerebezem, Juan M. Lema, and Mark C. M. van Loosdrecht. "Modeling product formation in anaerobic mixed culture fermentations." Biotechnology and Bioengineering 93, no. 3 (2006): 592–606. http://dx.doi.org/10.1002/bit.20765.

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Smid, Eddy J., and Christophe Lacroix. "Microbe–microbe interactions in mixed culture food fermentations." Current Opinion in Biotechnology 24, no. 2 (April 2013): 148–54. http://dx.doi.org/10.1016/j.copbio.2012.11.007.

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Esteves, Barbosa, Vasconcelos, Tavares, Mendes-Faia, Mira, and Mendes-Ferreira. "Characterizing the Potential of the Non-Conventional Yeast Saccharomycodes ludwigii UTAD17 in Winemaking." Microorganisms 7, no. 11 (October 23, 2019): 478. http://dx.doi.org/10.3390/microorganisms7110478.

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Non-Saccharomyces yeasts have received increased attention by researchers and winemakers, due to their particular contributions to the characteristics of wine. In this group, Saccharomycodes ludwigii is one of the less studied species. In the present study, a native S. ludwigii strain, UTAD17 isolated from the Douro wine region was characterized for relevant oenological traits. The genome of UTAD17 was recently sequenced. Its potential use in winemaking was further evaluated by conducting grape-juice fermentations, either in single or in mixed-cultures, with Saccharomyces cerevisiae, following two inoculation strategies (simultaneous and sequential). In a pure culture, S. ludwigii UTAD17 was able to ferment all sugars in a reasonable time without impairing the wine quality, producing low levels of acetic acid and ethyl acetate. The overall effects of S. ludwigii UTAD17 in a mixed-culture fermentation were highly dependent on the inoculation strategy which dictated the dominance of each yeast strain. Wines whose fermentation was governed by S. ludwigii UTAD17 presented low levels of secondary aroma compounds and were chemically distinct from those fermented by S. cerevisiae. Based on these results, a future use of this non-Saccharomyces yeast either in monoculture fermentations or as a co-starter culture with S. cerevisiae for the production of wines with greater expression of the grape varietal character and with flavor diversity could be foreseen.

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Robazza, Alberto, Claudia Welter, Christin Kubisch, Flávio César Freire Baleeiro, Katrin Ochsenreither, and Anke Neumann. "Co-Fermenting Pyrolysis Aqueous Condensate and Pyrolysis Syngas with Anaerobic Microbial Communities Enables L-Malate Production in a Secondary Fermentative Stage." Fermentation 8, no. 10 (October 4, 2022): 512. http://dx.doi.org/10.3390/fermentation8100512.

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The pyrolytic conversion of lignocellulosic biomass into fuels and chemicals is a promising option for the valorization of agricultural and forestry residues. However, technological developments are still needed to maximize product recovery and carbon fixation of the pyrolysis process. The pyrolysis aqueous condensate (PAC), a pyrolysis by-product, has a high water content and is highly toxic, hampering its use. The anaerobic digestion of PAC from different biomasses has been proven a viable technology for PAC valorization and detoxification, but its toxicity limits the methanogenic potential. Alternatively, methanation or VFA production from syngas by anaerobic mixed cultures are technologies of scientific interest. This study investigates the potential of a two-stage process to convert the carbon and energy in syngas and PAC into L-malate. PAC and syngas were co-fermented by two mixed cultures at 37 and 55 °C, identifying kinetic inhibitions and the effects of increasing PAC concentrations on the product pool. The media from selected mixed culture fermentations were then inoculated with Aspergillus oryzae for L-malate production. The results show that mixed cultures can perform simultaneous syngas fermentation and PAC detoxification. While PAC concentrations above 2% completely inhibited methanogenesis, CO consumption was inhibited at PAC concentrations above 5%, regardless of the temperature. In fermentations where PAC inhibited methanation, the mixed cultures channelled the carbon and electrons from syngas and PAC to volatile fatty acids or acetate/H2 production, depending on the incubation temperature. Substantial detoxification of PAC was observed under PAC concentrations up to 10% independently of the rates of syngas metabolism. PAC detoxification enabled the further valorization of the acetate produced via syngas and PAC fermentations into L-malate, achieving yields up to 0.17 mM/mM. These results are promising for the development of an integrated process that simultaneously detoxifies and recovers value from gaseous and aqueous waste streams originating from pyrolysis.

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Capece, Angela, Rocchina Pietrafesa, Gabriella Siesto, and Patrizia Romano. "Biotechnological Approach Based on Selected Saccharomyces cerevisiae Starters for Reducing the Use of Sulfur Dioxide in Wine." Microorganisms 8, no. 5 (May 15, 2020): 738. http://dx.doi.org/10.3390/microorganisms8050738.

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Sulfites are considered the main additives in winemaking for their antimicrobial, antioxidant and anti-oxidasic activities. The current concern about the potential negative effects of sulfur dioxide (SO2) on consumer health has focused the interest on replacing or reducing SO2 use. Our work aims to develop a strategy based on the use of selected starter culture, able to perform wine fermentation without SO2 addition. Four selected Saccharomyces cerevisiae indigenous strains were tested as mixed starter cultures in laboratory scale fermentations. The starter culture, characterized by a similar percentage of dominance of both strains composing the mixed starter and able to produce a wine characterized by the best combination of chemical and aromatic characteristics, was chosen. This mixed culture was tested as a starter at pilot scale with and without SO2 addition, by using a higher inoculum level in the vinification without SO2. The selected starter confirmed higher dominance ability in vinification without SO2 addition than in SO2-added fermentation, demonstrating that sulfite addition is not a guarantee to reach an absolute dominance of starter culture on indigenous microflora. The proposed biotechnological tool allowed to produce good quality wines possessing also “functional properties”, as NO-SO2 added wines were characterized by high polyphenol content and antioxidant activity.

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van Wyk, Niel, Isak S. Pretorius, and Christian von Wallbrunn. "Assessing the Oenological Potential of Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii Strains in Mixed-Culture Grape Must Fermentation with Saccharomyces cerevisiae." Fermentation 6, no. 2 (May 7, 2020): 49. http://dx.doi.org/10.3390/fermentation6020049.

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Recently, there has been a growing interest in the role of non-Saccharomyces yeast (NSY) as a coculturing partner with Saccharomyces cerevisiae during grape must fermentation. We investigated three new strains, namely Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii, for their oenological potential in mixed-culture micro-vinifications with S. cerevisiae Vin13 using Muscaris grape must. None of the NSY strains impeded the fermentation performance as all the mixed-culture experiments finished at the same time. Coculturing with N. ishiwadae yielded significantly higher concentrations of ethyl and acetate esters in the final wine product. Apart from higher acetic acid levels, wines produced with C. railenensis and D. hansenii yielded much lower esters concentrations. The concentrations of certain terpenes and norisoprenoids were also significantly modulated in the mixed-culture fermentations. This study reveals the rarely reported species of N. ishiwadae as a promising coculturing partner for increasing aroma-active compounds in a wine.

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Rahmadi, A., Y. Yunus, M. Ulfah, K. P. Candra, and S. Suwasono. "Microorganism population, theobromine, antioxidant, and FTIR analysis of Samarinda cocoa bean fermented with Saccharomyces cerevisiae and Acetobacter aceti." Food Research 4, no. 6 (July 27, 2020): 1912–20. http://dx.doi.org/10.26656/fr.2017.4(6).178.

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This research aimed to observe S. cerevisiae and A. aceti induced fermentation of cocoa bean from Samarinda, Indonesia, in comparison to commercial cocoa bean in terms of microbial population, pH, total acids, total phenols, theobromine, antioxidant capacity, and FTIR profile. Cocoa beans were fermented with a boxed fermentation method resembling commercial plantation for four days at ambient box temperature (35-40°C). Four fermentation samples were produced which were spontaneous, 2% Saccharomyces cerevisiae, Acetobacter aceti, or mixed culture (S. cerevisiae and A. aceti) induced fermentations. Total Plate Count (TPC) and Total Yeast-Mold (TYM), pH, total phenol, theobromine, antioxidant activity, and FTIR analyses were performed according to the established method. There was no significant difference in the microbe population in all fermented cocoa. Mixed culture fermented cocoa had a slightly lower final pH. S. cerevisiae fermented cocoa produced the highest total phenol compared to the same compound content in other fermented cocoa. The mixed culture fermented cocoa had better theobromine content 162.3±22.6 ppm, antioxidant capacity 424.9±3.3 ppm, and the closest theobromine and caffeine identification zones to commercial cocoa samples. The use of mixed culture of S. cerevisiae and A. aceti is suggested as the better inoculum to ferment cocoa bean at local farms.

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Kleerebezem, R., M. F. Temudo, M. C. M. van Loosdrecht, and J. Rodríguez. "Modeling mixed culture fermentations; the role of different electron carriers." Water Science and Technology 57, no. 4 (March 1, 2008): 493–97. http://dx.doi.org/10.2166/wst.2008.094.

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A recently established mixed culture fermentation (MCF) model has been modified to account for the role of different electron carriers in the process. The MCF-model predicts the product spectrum as a function of the actual environmental conditions using a thermodynamic optimization criterion while satisfying a number of constraints. Other improvements made to the original model are the inclusion of formate as fermentation end-product, and gas-liquid mass transfer. The model is adequately capable of reproducing experimental results in terms of butyrate and formate versus hydrogen/carbon dioxide production. The model is not capable of predicting the production of an ethanol/acetate mixture as measured at higher pH-values, suggesting specific biochemical control. Catabolic acetate production can potentially be explained by anabolic requirements for a specific electron donor like NADH.

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de Kok, Stefan, Jasper Meijer, Mark C. M. van Loosdrecht, and Robbert Kleerebezem. "Impact of dissolved hydrogen partial pressure on mixed culture fermentations." Applied Microbiology and Biotechnology 97, no. 6 (September 21, 2012): 2617–25. http://dx.doi.org/10.1007/s00253-012-4400-x.

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Joran, Alexis, Géraldine Klein, Chloé Roullier-Gall, and Hervé Alexandre. "Multiparametric Approach to Interactions between Saccharomyces cerevisiae and Lachancea thermotolerans during Fermentation." Fermentation 8, no. 6 (June 17, 2022): 286. http://dx.doi.org/10.3390/fermentation8060286.

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The aim of a significant part of current wine technology research is to better understand and monitor mixed culture fermentations and optimize the microbiological processes and characteristics of the final wine. In this context, the yeast couple formed by Lachancea thermotolerans and Saccharomyces cerevisiae is of particular interest. The diverse results observed in the literature have shown that wine characteristics are dependent on both interactions between yeasts and environmental and fermentation parameters. Here, we took a multiparametric approach to study the impact of fermentation parameters on three different but related aspects of wine fermentation: population dynamics, fermentation, and volatile compound production. An experimental design was used to assess the effects of four independent factors (temperature, oxygenation, nitrogen content, inoculum ratio) on variables representing these three aspects. Temperature and, to a lesser extent, oxygenation and the inoculum ratio, were shown to constitute key factors in optimizing the presence of Lachancea thermotolerans during fermentation. The inoculum ratio also appeared to greatly impact lactic acid production, while the quantity of nitrogen seemed to be involved more in the management of aroma compound production. These results showed that a global approach to mixed fermentations is not only pertinent, but also constitutes an important tool for controlling them.

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Gomes, Luiz Humberto, Keila Maria Roncato Duarte, Felipe Gabriel Andrino, Ana Maria Brancalion Giacomelli, and Flavio Cesar Almeida Tavares. "A vector carrying the GFP gene (Green fluorescent protein) as a yeast marker for fermentation processes." Scientia Agricola 57, no. 4 (December 2000): 713–16. http://dx.doi.org/10.1590/s0103-90162000000400018.

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Contaminant yeasts spoil pure culture fermentations and cause great losses in quality and product yields. They can be detected by a variety of methods although none being so efficient for early detection of contaminant yeast cells that appear at low frequency. Pure cultures bearing genetic markers can ease the direct identification of cells and colonies among contaminants. Fast and easy detection are desired and morphological markers would even help the direct visualization of marked pure cultures among contaminants. The GFP gene for green fluorescent protein of Aquorea victoria, proved to be a very efficient marker to visualize transformed cells in mixed populations and tissues. To test this marker in the study of contaminated yeast fermentations, the GFP gene was used to construct a vector under the control of the ADH2 promoter (pYGFP3). Since ADH2 is repressed by glucose the expression of the protein would not interfere in the course of fermentation. The transformed yeasts with the vector pYGFP3 showed high stability and high bioluminescence to permit identification of marked cells among a mixed population of cells. The vector opens the possibility to conduct further studies aiming to develop an efficient method for early detection of spoilage yeasts in industrial fermentative processes.

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Ribeiro, Carlos Alberto França, and Jorge Horii. "Negative H2S character and flocculation as yeast strain markers for inoculum recovery." Scientia Agricola 61, no. 3 (June 2004): 292–97. http://dx.doi.org/10.1590/s0103-90162004000300009.

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Routine identification of yeast behavior is essential to measure the control of the alcohol production process and to maintain product quality standards. This work utilized the non-hydrogen sulfide production and flocculation traits as characteristic strain markers for the evaluation of cell recycling during the alcoholic fermentation process for production of sugarcane alcohol. This study evaluated the behavior of a recombinant yeast bank made by protoplast fusion, for strain screening purposes; strain fermentative kinetics in comparison to commercial baker yeast; viability and recovery of the selected strain on differential media, after five consecutive fermentation batches; and the recovery of the selected strain from fermentation with mixed strain cultures. The strain selected for the H2S negative character kept its viability during successive recyclings, with contamination levels not detected by the method of analysis. It also presented a kinetic behavior similar to that of baker yeast, either in single or mixed culture fermentations, opening new possibilities for further work on quality control of cell recycling in the alcoholic fermentation process.

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Zagrodnik, Roman. "Optimization of Hydrogen Production by Co-Culture of Clostridium beijerinckii and Rhodobacter sphaeroides Bacteria." Advances in Science and Technology 93 (October 2014): 90–95. http://dx.doi.org/10.4028/www.scientific.net/ast.93.90.

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The biological methods of hydrogen generation have attracted a significant interest recently. In this work the hybrid system applying both dark fermentation bacteria in co-culture was tested. Objective of this work was to investigate the optimization of different parameters on co-culture of Clostridium beijerinckii DSM-791 and Rhodobacter sphaeroides O.U.001. The effect of glucose concentration (1–5 g/L), temperature and initial pH (6,5–7,5) was analyzed. Moreover the influence of organic nitrogen sources were tested for their capacity to support hydrogen production (yeast extract, peptone, glutamic acid). Fermentations were conducted in batch tests with glucose as sole substrate. Hydrogen production in mixed culture was compared with pure cultures. The process was greatly affected by pH and light/dark bacteria ratio. Liquid metabolites, namely acetic and butyric acids, from the dark fermentation step were the source of organic carbon for photosynthetic bacteria. This increased the hydrogen yield in comparison to single-step dark fermentation to over 4 mol H2/mol glucose. Obtained results showed that combination of photo and dark fermentation may increase hydrogen production and conversion efficiency of complex substrates or wastewaters.

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Andorrà, Imma, María Berradre, Albert Mas, Braulio Esteve-Zarzoso, and Jose M. Guillamón. "Effect of mixed culture fermentations on yeast populations and aroma profile." LWT 49, no. 1 (November 2012): 8–13. http://dx.doi.org/10.1016/j.lwt.2012.04.008.

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Xafenias, Nikolaos, MarySandra Oluchi Anunobi, and Valeria Mapelli. "Electrochemical startup increases 1,3-propanediol titers in mixed-culture glycerol fermentations." Process Biochemistry 50, no. 10 (October 2015): 1499–508. http://dx.doi.org/10.1016/j.procbio.2015.06.020.

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van Beek, Sylvie, and Fergus G. Priest. "Decarboxylation of Substituted Cinnamic Acids by Lactic Acid Bacteria Isolated during Malt Whisky Fermentation." Applied and Environmental Microbiology 66, no. 12 (December 1, 2000): 5322–28. http://dx.doi.org/10.1128/aem.66.12.5322-5328.2000.

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ABSTRACT Seven strains of Lactobacillus isolated from malt whisky fermentations and representing Lactobacillus brevis,L. crispatus, L. fermentum, L. hilgardii, L. paracasei, L. pentosus, andL. plantarum contained genes for hydroxycinnamic acid (p-coumaric acid) decarboxylase. With the exception ofL. hilgardii, these bacteria decarboxylatedp-coumaric acid and/or ferulic acid, with the production of 4-vinylphenol and/or 4-vinylguaiacol, respectively, although the relative activities on the two substrates varied between strains. The addition of p-coumaric acid or ferulic acid to cultures ofL. pentosus in MRS broth induced hydroxycinnamic acid decarboxylase mRNA within 5 min, and the gene was also induced by the indigenous components of malt wort. In a simulated distillery fermentation, a mixed culture of L. crispatus and L. pentosus in the presence of Saccharomyces cerevisiae decarboxylated added p-coumaric acid more rapidly than the yeast alone but had little activity on added ferulic acid. Moreover, we were able to demonstrate the induction of hydroxycinnamic acid decarboxylase mRNA under these conditions. However, in fermentations with no additional hydroxycinnamic acid, the bacteria lowered the final concentration of 4-vinylphenol in the fermented wort compared to the level seen in a pure-yeast fermentation. It seems likely that the combined activities of bacteria and yeast decarboxylate p-coumaric acid and then reduce 4-vinylphenol to 4-ethylphenol more effectively than either microorganism alone in pure cultures. Although we have shown that lactobacilli participate in the metabolism of phenolic compounds during malt whisky fermentations, the net result is a reduction in the concentrations of 4-vinylphenol and 4-vinylguaiacol prior to distillation.

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De Gioia, Marianna, Pasquale Russo, Nicola De Simone, Francesco Grieco, Giuseppe Spano, Vittorio Capozzi, and Mariagiovanna Fragasso. "Interactions among Relevant Non-Saccharomyces, Saccharomyces, and Lactic Acid Bacteria Species of the Wine Microbial Consortium: Towards Advances in Antagonistic Phenomena and Biocontrol Potential." Applied Sciences 12, no. 24 (December 12, 2022): 12760. http://dx.doi.org/10.3390/app122412760.

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The topic of microbial interactions is of notable relevance in oenology, being connected with their impact on microbial biodiversity and wine quality. The interactions among different couples of microorganisms, in particular yeasts and lactic acid bacteria representative of the must/wine microbial consortium, have been tested in this study. This interaction’s screening has been implemented by means of plate assays, using culture medium, grape juice, and wine agar as substrates. Different antagonistic phenomena have been detected, belonging to the following interaction categories: yeast-yeast, yeast-bacteria, bacteria-yeast, and bacteria-bacteria. In general, the inhibitory activity has been observed in all three media agar used as substrates, resulting in more frequent on culture medium, followed by grape juice and, finally, wine. Specifically, the work is one of the first reports demonstrating the reciprocal interactions between non-Saccharomyces yeasts (NSY) and malolactic bacteria. The findings shed new light on the co-inoculation of the yeast starter culture with malolactic bacteria, as well as the biocontrol potential of Lactic Acid Bacteria (LAB) strains. Highlighted microbial interactions are relevant for the management of alcoholic fermentation, malolactic fermentation, and the development of distinctive aroma profiles, control of spoilage yeasts, and the selection of tailored mixed starter cultures. In addition, the plate assay method could be a fast, cheap, and suitable method to exclude negative interactions among Saccharomyces spp., NSY, and malolactic bacteria during trials from regional spontaneous fermentations with the aim to select tailored mixed starter cultures.

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González-Cabaleiro, Rebeca, Juan M. Lema, and Jorge Rodríguez. "Metabolic Energy-Based Modelling Explains Product Yielding in Anaerobic Mixed Culture Fermentations." PLOS ONE 10, no. 5 (May 18, 2015): e0126739. http://dx.doi.org/10.1371/journal.pone.0126739.

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Escudero-Abarca, Blanca I., M. Guadalupe Aguilar-Uscanga, Patricia M. Hayward-Jones, Patricia Mendoza, Mario Ram�rez, and Leticia G�mez-Rivas. "Selective antimicrobial action of chitosan against spoilage yeasts in mixed culture fermentations." Journal of Industrial Microbiology and Biotechnology 31, no. 1 (January 1, 2004): 16–22. http://dx.doi.org/10.1007/s10295-004-0112-2.

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Gamero, Amparo, Annereinou Dijkstra, Bart Smit, and Catrienus de Jong. "Aromatic Potential of Diverse Non-Conventional Yeast Species for Winemaking and Brewing." Fermentation 6, no. 2 (May 11, 2020): 50. http://dx.doi.org/10.3390/fermentation6020050.

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Traditionally, Saccharomyces species are those used to conduct industrial alcoholic fermentations. Recently, an increasing interest has arisen with respect to the potential of so-called non-conventional yeasts to improve wine and beer aroma profiles, keeping the particular terroir of each region or for the development of craft beers. In this study, the potential of diverse non-conventional yeasts to improve aroma in winemaking and brewing was investigated, testing several pure and mixed culture combinations. In addition, a comparison between microscale and labscale was carried out in order to assess the value of microwine and microbeer as screening tools. The results indicated that non-Saccharomyces yeasts were good candidates to enhance or diversify aroma profiles in alcoholic beverages, especially regarding acetate ester yield and fruity aromas. However, mixed cultures with Saccharomyces spp. are normally required to achieve a successful fermentation. The adjustment of pithing ratios is crucial for this purpose. Microscale is presented as an effective and efficient screening tool to compare different culture combinations, although scaling-up will always be necessary in order to get results closer to real winemaking or brewing processes.

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Dutraive, Ophélie, Santiago Benito, Stefanie Fritsch, Beata Beisert, Claus-Dieter Patz, and Doris Rauhut. "Effect of Sequential Inoculation with Non-Saccharomyces and Saccharomyces Yeasts on Riesling Wine Chemical Composition." Fermentation 5, no. 3 (September 1, 2019): 79. http://dx.doi.org/10.3390/fermentation5030079.

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In recent years, studies have reported the positive influence of non-Saccharomyces yeast on wine quality. Many grape varieties under mixed or sequential inoculation show an overall positive effect on aroma enhancement. A potential impact by non-Saccharomyces yeast on volatile and non-volatile compounds should benefit the flavor of Riesling wines. Following this trend, four separate sequential fermentations (using the non-Saccharomyces yeasts Torulaspora delbrueckii, Metschnikowia pulcherrima, Pichia kluyveri, and Lachancea thermotolerans with Saccharomyces cerevisiae) were carried out on Riesling must and compared to a pure culture of S. cerevisiae. Sequential fermentations influenced the final wine aroma. Significant differences were found in esters, acetates, higher alcohols, fatty acids, and low volatile sulfur compounds between the different trials. Other parameters, including the production of non-volatile compounds, showed significant differences. This fermentation process not only allows the modulation of wine aroma but also chemical parameters such as glycerol, ethanol, alcohol, acidity, or fermentation by-products. These potential benefits of wine diversity should be beneficial to the wine industry.

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Benítez-Cabello, Antonio, Francisco Rodríguez-Gómez, M. Lourdes Morales, Antonio Garrido-Fernández, Rufino Jiménez-Díaz, and Francisco Noé Arroyo-López. "Lactic Acid Bacteria and Yeast Inocula Modulate the Volatile Profile of Spanish-Style Green Table Olive Fermentations." Foods 8, no. 8 (July 24, 2019): 280. http://dx.doi.org/10.3390/foods8080280.

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In this work, Manzanilla Spanish-style green table olive fermentations were inoculated with Lactobacillus pentosus LPG1, Lactobacillus pentosus Lp13, Lactobacillus plantarum Lpl15, the yeast Wickerhanomyces anomalus Y12 and a mixed culture of all them. After fermentation (65 days), their volatile profiles in brines were determined by gas chromatography-mass spectrometry analysis. A total of 131 volatile compounds were found, but only 71 showed statistical differences between at least, two fermentation processes. The major chemical groups were alcohols (32), ketones (14), aldehydes (nine), and volatile phenols (nine). Results showed that inoculation with Lactobacillus strains, especially L. pentosus Lp13, reduced the formation of volatile compounds. On the contrary, inoculation with W. anomalus Y12 increased their concentrations with respect to the spontaneous process, mainly of 1-butanol, 2-phenylethyl acetate, ethanol, and 2-methyl-1-butanol. Furthermore, biplot and biclustering analyses segregated fermentations inoculated with Lp13 and Y12 from the rest of the processes. The use of sequential lactic acid bacteria and yeasts inocula, or their mixture, in Spanish-style green table olive fermentation could be advisable practice for producing differentiated and high-quality products with improved aromatic profile.

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Postigo, Vanesa, Paula Sanz, Margarita García, and Teresa Arroyo. "Impact of Non-Saccharomyces Wine Yeast Strains on Improving Healthy Characteristics and the Sensory Profile of Beer in Sequential Fermentation." Foods 11, no. 14 (July 8, 2022): 2029. http://dx.doi.org/10.3390/foods11142029.

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The use of non-Saccharomyces yeasts in brewing is a useful tool for developing new products to meet the growing consumer demand for innovative products. Non-Saccharomyces yeasts can be used both in single and in mixed fermentations with Saccharomyces cerevisiae, as they are able to improve the sensory profile of beers, and they can be used to obtain functional beers (with a low ethanol content and melatonin production). The aim of this study was to evaluate this capacity in eight non-Saccharomyces strains isolated from Madrid agriculture. For this purpose, single fermentations were carried out with non-Saccharomyces strains and sequential fermentations with non-Saccharomyces and the commercial strain SafAle S-04. The Wickerhamomyces anomalus strain CLI 1028 was selected in pure culture for brewing beer with a low ethanol content (1.25% (v/v)) for its fruity and phenolic flavours and the absence of wort flavours. The best-evaluated strains in sequential fermentation were CLI 3 (Hanseniaspora vineae) and CLI 457 (Metschnikowia pulcherrima), due to their fruity notes as well as their superior bitterness, body, and balance. Volatile compounds and melatonin production were analysed by GC and HPLC, respectively. The beers were sensory-analysed by a trained panel. The results of the study show the potential of non-Saccharomyces strains in the production of low-alcohol beers, and as a flavour enhancement in sequential fermentation.

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Liu, Tian Ming, Hui Hui Wang, Ke Wang, Hui Wang, Xiu Bao Zhao, and Yu Qi Tang. "Enology Characteristics of Yeasts Saccharomyces cerevisiae and Hanseniaspora uvarum Selected for Chinese Original Wine." Advanced Materials Research 365 (October 2011): 233–39. http://dx.doi.org/10.4028/www.scientific.net/amr.365.233.

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The enology characteristics were studied by three yeast strains of pure and mixed cultures of Saccharomyces cerevisiae QM, ZYFJQ and Hanseniaspora uvarum YQY with Cabernet sauvignon grape,respectively, while the commercial Saccharomyces cerevisiae RC212 was made as a control, in order to screen excellent yeast strains or the combination of those for the original wine. Chemical indices of the wines by three stiains were analyzed including ethanol, total acidity, volatile acidity and residual reducing sugar. Flavor compounds in wines and in must were extracted by dichloromethane and identified by GC–MS.The results showed that the chemical indices of the wine from selected strains could satisfy with the demand of Chinese national standard, and the volatiles were mainly the 2-phenylethanol, which shaped the main characteristics of wine aroma components. yeast strain QM and YQY got the best balance between acetate and alcohols. The best volatiles of wine was obtained from the mixed fermentations than from the pure or from the control ones. ndigenous yeast strains from grape played an important role on the types and amounts of flavor compounds in mixed culture fermentation. The yeasts could have potential applications to the original winemaking.

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Regueira, A., R. González-Cabaleiro, I. D. Ofiţeru, J. Rodríguez, and J. M. Lema. "Electron bifurcation mechanism and homoacetogenesis explain products yields in mixed culture anaerobic fermentations." Water Research 141 (September 2018): 349–56. http://dx.doi.org/10.1016/j.watres.2018.05.013.

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Bautista-Rosales, Pedro Ulises, Juan Arturo Ragazzo-Sánchez, Gabriela Ruiz-Montañez, Rosa Isela Ortiz-Basurto, Guadalupe Luna-Solano, and Montserrat Calderón-Santoyo. "Saccharomyces cerevisiaeMixed Culture of Blackberry (Rubus ulmifoliusL.) Juice: Synergism in the Aroma Compounds Production." Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/163174.

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Blackberry (Rubussp.) juice was fermented using four different strains ofSaccharomyces cerevisiae(Vitilevure-CM4457, Enoferm-T306, ICV-K1, and Greroche Rhona-L3574) recognized because of their use in the wine industry. A medium alcoholic graduation spirit (<6GL°) with potential to be produced at an industrial scale was obtained. Alcoholic fermentations were performed at28C°, 200 rpm, and noncontrolled pH. The synergistic effect on the aromatic compounds production during fermentation in mixed culture was compared with those obtained by monoculture and physic mixture of spirits produced in monoculture. The aromatic composition was determined by HS-SPME-GC. The differences in aromatic profile principally rely on the proportions in aromatic compounds and not on the number of those compounds. The multivariance analysis, principal component analysis (PCA), and factorial discriminant analysis (DFA) permit to demonstrate the synergism between the strains.

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Lefeber, Timothy, Maarten Janssens, Nicholas Camu, and Luc De Vuyst. "Kinetic Analysis of Strains of Lactic Acid Bacteria and Acetic Acid Bacteria in Cocoa Pulp Simulation Media toward Development of a Starter Culture for Cocoa Bean Fermentation." Applied and Environmental Microbiology 76, no. 23 (October 1, 2010): 7708–16. http://dx.doi.org/10.1128/aem.01206-10.

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ABSTRACT The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

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Sun, Wen Jing, Lin Yu, Si Lian Yu, Feng Jie Cui, Yan Zheng Zhou, Qiang Zhou, and Lei Sun. "Kinetic Modeling of 2-Keto-Gluconic Acid (2KGA) Production from Rice Starch Hydrolysate Using Pseudomonas fluorescens AR4." Advanced Materials Research 550-553 (July 2012): 1144–50. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.1144.

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Kinetic models are proposed for the 2KGA batch production from rice starch hydrolysate containing 162 g/L of glucose by Pseudomonas fluorescens AR4. The models include terms accounting for both substrate and product inhibitions. Experimental data collected from the batch fermentations were used to estimate parameters and also to validate the models proposed. The growth of Ps. fluorescens could be expressed by a Logistic model wihout incorporating inhibitions of glucose and organic acids accumulated in the culture broth. The Luedeking–Piret model was able to describe the 2KGA formation as the fermentation proceeded with a mixed-growth-associated pattern. In all cases, the model simulation matched well with the experimental observations, which made it possible to elucidate the fermentation characteristics of Ps. fluorescens AR4 during efficient 2KGA production from glucose.

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Navarro, Yurena, María-Jesús Torija, Albert Mas, and Gemma Beltran. "Viability-PCR Allows Monitoring Yeast Population Dynamics in Mixed Fermentations Including Viable but Non-Culturable Yeasts." Foods 9, no. 10 (September 27, 2020): 1373. http://dx.doi.org/10.3390/foods9101373.

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The use of controlled mixed inocula of Saccharomyces cerevisiae and non-Saccharomyces yeasts is a common practice in winemaking, with Torulaspora delbrueckii, Lachancea thermotolerans and Metschnikowia pulcherrima being the most commonly used non-Saccharomyces species. Although S. cerevisiae is usually the dominant yeast at the end of mixed fermentations, some non-Saccharomyces species are also able to reach the late stages; such species may not grow in culture media, which is a status known as viable but non-culturable (VBNC). Thus, an accurate methodology to properly monitor viable yeast population dynamics during alcoholic fermentation is required to understand microbial interactions and the contribution of each species to the final product. Quantitative PCR (qPCR) has been found to be a good and sensitive method for determining the identity of the cell population, but it cannot distinguish the DNA from living and dead cells, which can overestimate the final population results. To address this shortcoming, viability dyes can be used to avoid the amplification and, therefore, the quantification of DNA from non-viable cells. In this study, we validated the use of PMAxx dye (an optimized version of propidium monoazide (PMA) dye) coupled with qPCR (PMAxx-qPCR), as a tool to monitor the viable population dynamics of the most common yeast species used in wine mixed fermentations (S. cerevisiae, T. delbrueckii, L. thermotolerans and M. pulcherrima), comparing the results with non-dyed qPCR and colony counting on differential medium. Our results showed that the PMAxx-qPCR assay used in this study is a reliable, specific and fast method for quantifying these four yeast species during the alcoholic fermentation process, being able to distinguish between living and dead yeast populations. Moreover, the entry into VBNC status was observed for the first time in L. thermotolerans and S. cerevisiae during alcoholic fermentation. Further studies are needed to unravel which compounds trigger this VBNC state during alcoholic fermentation in these species, which would help to better understand yeast interactions.

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Fan, Guangsen, Chao Teng, Dai Xu, Zhilei Fu, Pengxiao Liu, Qiuhua Wu, Ran Yang, and Xiuting Li. "Improving Ethyl Acetate Production in Baijiu Manufacture by Wickerhamomyces anomalus and Saccharomyces cerevisiae Mixed Culture Fermentations." BioMed Research International 2019 (January 13, 2019): 1–11. http://dx.doi.org/10.1155/2019/1470543.

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Ethyl acetate content has strong influence on the style and quality of Baijiu. Therefore, this study investigated the effect of Saccharomyces cerevisiae Y3401 on the production of ethyl acetate by Wickerhamomyces anomalus Y3604. Analysis of cell growth showed that Y3401 influences Y3604 by nutrient competition and inhibition by metabolites, while the effect of Y3604 on Y3401 was mainly competition for nutrients. Mixed fermentation with two yeasts was found to produce more ethyl acetate than a single fermentation. The highest yield of ethyl acetate was 2.99 g/L when the inoculation ratio of Y3401:Y3604 was 1:2. Synergistic fermentation of both yeasts improved ethyl acetate production and increased the content of other flavor compounds in liquid and simulated solid-state fermentation for Baijiu. Saccharomyces cerevisiae had a positive effect on ethyl acetate production in mixed culture and provides opportunities to alter the aroma and flavor perception of Baijiu.

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Horisawa, Sakae, Akie Inoue, and Yuka Yamanaka. "Direct Ethanol Production from Lignocellulosic Materials by Mixed Culture of Wood Rot Fungi Schizophyllum commune, Bjerkandera adusta, and Fomitopsis palustris." Fermentation 5, no. 1 (February 15, 2019): 21. http://dx.doi.org/10.3390/fermentation5010021.

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The cost of bioethanol production from lignocellulosic materials is relatively high because the additional processes of delignification and saccharification are required. Consolidated bioprocessing (CBP) simultaneously uses the multiple processes of delignification, saccharification, and fermentation in a single reactor and has the potential to solve the problem of cost. Some wood-degrading basidiomycetes have lignin- and cellulose-degrading abilities as well as ethanol fermentation ability. The white rot fungus Schizophyllum commune NBRC 4928 was selected as a strong fermenter from a previous study. The lignin-degrading fungus Bjerkandera adusta and polysaccharide-degrading fungus Fomitopsis palustris were respectively added to S. commune ethanol fermentations to help degrade lignocellulosic materials. Bjerkandera adusta produced more ligninase under aerobic conditions, so a switching aeration condition was adopted. The mixed culture of S. commune and B. adusta promoted direct ethanol production from cedar wood. Fomitopsis palustris produced enzymes that released glucose from both carboxymethylcellulose and microcrystalline cellulose. The mixed culture of S. commune and F. palustris did not enhance ethanol production from cedar. The combination of S. commune and cellulase significantly increased the rate of ethanol production. The results suggest that CBP for ethanol production from cellulosic material can be achieved by using multiple fungi in one reactor.

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Tangyu, Muzi, Jeroen Muller, Christoph J. Bolten, and Christoph Wittmann. "Fermentation of plant-based milk alternatives for improved flavour and nutritional value." Applied Microbiology and Biotechnology 103, no. 23-24 (November 4, 2019): 9263–75. http://dx.doi.org/10.1007/s00253-019-10175-9.

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Abstract Non-dairy milk alternatives (or milk analogues) are water extracts of plants and have become increasingly popular for human nutrition. Over the years, the global market for these products has become a multi-billion dollar business and will reach a value of approximately 26 billion USD within the next 5 years. Moreover, many consumers demand plant-based milk alternatives for sustainability, health-related, lifestyle and dietary reasons, resulting in an abundance of products based on nuts, seeds or beans. Unfortunately, plant-based milk alternatives are often nutritionally unbalanced, and their flavour profiles limit their acceptance. With the goal of producing more valuable and tasty products, fermentation can help to the improve sensory profiles, nutritional properties, texture and microbial safety of plant-based milk alternatives so that the amendment with additional ingredients, often perceived as artificial, can be avoided. To date, plant-based milk fermentation mainly uses mono-cultures of microbes, such as lactic acid bacteria, bacilli and yeasts, for this purpose. More recently, new concepts have proposed mixed-culture fermentations with two or more microbial species. These approaches promise synergistic effects to enhance the fermentation process and improve the quality of the final products. Here, we review the plant-based milk market, including nutritional, sensory and manufacturing aspects. In addition, we provide an overview of the state-of-the-art fermentation of plant materials using mono- and mixed-cultures. Due to the rapid progress in this field, we can expect well-balanced and naturally fermented plant-based milk alternatives in the coming years.

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Padilla, Beatriz, Jose Gil, and Paloma Manzanares. "Challenges of the Non-Conventional Yeast Wickerhamomyces anomalus in Winemaking." Fermentation 4, no. 3 (August 20, 2018): 68. http://dx.doi.org/10.3390/fermentation4030068.

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Nowadays it is widely accepted that non-Saccharomyces yeasts, which prevail during the early stages of alcoholic fermentation, contribute significantly to the character and quality of the final wine. Among these yeasts, Wickerhamomyces anomalus (formerly Pichia anomala, Hansenula anomala, Candida pelliculosa) has gained considerable importance for the wine industry since it exhibits interesting and potentially exploitable physiological and metabolic characteristics, although its growth along fermentation can still be seen as an uncontrollable risk. This species is widespread in nature and has been isolated from different environments including grapes and wines. Its use together with Saccharomyces cerevisiae in mixed culture fermentations has been proposed to increase wine particular characteristics. Here, we review the ability of W. anomalus to produce enzymes and metabolites of oenological relevance and we discuss its potential as a biocontrol agent in winemaking. Finally, biotechnological applications of W. anomalus beyond wine fermentation are briefly described.

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Schwan, Rosane Freitas. "Cocoa Fermentations Conducted with a Defined Microbial Cocktail Inoculum." Applied and Environmental Microbiology 64, no. 4 (April 1, 1998): 1477–83. http://dx.doi.org/10.1128/aem.64.4.1477-1483.1998.

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ABSTRACT Cocoa fermentations were performed in wooden boxes under the following four experimental regimens: beans naturally fermented with wild microflora; aseptically prepared beans with no inoculum; and beans inoculated with a defined cocktail containing microorganisms at a suitable concentration either at zero time or by using phased additions at appropriate times. The cocktail used consisted of a yeast,Saccharomyces cerevisiae var. chevalieri, two lactic acid bacterial species, Lactobacillus lactis andLactobacillus plantarum, and two acetic acid bacterial species, Acetobacter aceti and Gluconobacter oxydans subsp. suboxydans. The parameters measured were cell counts (for yeasts, filamentous fungi, lactic acid bacteria, acetic acid bacteria, and spore formers, including reisolation and identification of all residual cell types), sugar, ethanol, acetic acid, and lactic acid contents (and contents of other organic acids), pH, and temperature. A cut test for bean quality and a sensorial analysis of chocolate made from the beans were also performed. The natural fermentation mimicked exactly the conditions in 800-kg boxes on farms. The aseptic box remained largely free of microflora throughout the study, and no significant biochemical changes occurred. With the zero-time inoculum the fermentation was almost identical to the natural fermentation. The fermentation with the phased-addition inoculum was similar, but many changes in parameters were slower and less pronounced, which led to a slightly poorer end product. The data show that the nearly 50 common species of microorganisms found in natural fermentations can be replaced by a judicious selection and concentration of members of each physiological group. This is the first report of successful use of a defined, mixed starter culture in such a complex fermentation, and it should lead to chocolate of more reliable and better quality.

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Checchia, Ilaria, Renato L. Binati, Eleonora Troiano, Maurizio Ugliano, Giovanna E. Felis, and Sandra Torriani. "Unravelling the Impact of Grape Washing, SO2, and Multi-Starter Inoculation in Lab-Scale Vinification Trials of Withered Black Grapes." Fermentation 7, no. 1 (March 23, 2021): 43. http://dx.doi.org/10.3390/fermentation7010043.

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Wine quality is strongly affected by chemical composition and microbial population of grape must, which, in turn, are influenced by several post-harvest treatments, including grape withering. Different strategies have been suggested to manage the fermenting must microbiota, as it plays a central role in the outcomes of both spontaneous and guided fermentations. This study aimed at evaluating the impact of grape washing, SO2 addition, and selected starter culture inoculation on population dynamics, fermentation kinetics, and main oenological parameters in lab-scale trials, focusing on withered grapes usually used for Amarone production. Although grape washing treatment was effective in removing heavy metals and undesirable microorganisms from grape berry surface, inoculation of multi-starter cultures impacted more fermentation rates. Further, both grape washing and starter inoculation procedures had a remarkable impact on wine chemical characteristics, while 30 mg/L SO2 addition did not significantly affect the fermentation process. In summary, the best strategy in terms of limiting off-flavors and potentially reducing the need for SO2 addition in wine from withered grapes was the use of yeast starters, particularly mixed cultures composed by selected strains of Metschnikowia spp. and Saccharomyces cerevisiae. Application of a washing step before winemaking showed a potential to improve organoleptic characteristics of wine.

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PEREZCHAIA, A. "Short-chain fatty acids modulate growth of lactobacilli in mixed culture fermentations with propionibacteria." International Journal of Food Microbiology 26, no. 3 (August 1995): 365–74. http://dx.doi.org/10.1016/0168-1605(94)00148-y.

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Tsafrakidou, Panagiota, Konstantina Tsigkou, Argyro Bekatorou, Maria Kanellaki, and Athanasios A. Koutinas. "Anaerobic Acidogenic Fermentation of Cellobiose by Immobilized Cells: Prediction of Organic Acids Production by Response Surface Methodology." Processes 9, no. 8 (August 19, 2021): 1441. http://dx.doi.org/10.3390/pr9081441.

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Response surface methodology was used to derive a prediction model for organic acids production by anaerobic acidogenic fermentation of cellobiose, using a mixed culture immobilized on γ-alumina. Three parameters (substrate concentration, temperature, and initial pH) were evaluated. In order to determine the limits of the parameters, preliminary experiments at 37 °C were conducted using substrates of various cellobiose concentrations and pH values. Cellobiose was used as a model sugar for subsequent experiments with lignocellulosic biomass. The culture was well adapted to cellobiose by successive subculturing at 37 °C in synthetic media (with 100:5:1 COD:N:P ratio). The experimental data of successive batch fermentations were fitted into a polynomial model for the total organic acids concentration in order to derive a predictive model that could be utilized as a tool to predict fermentation results when lignocellulosic biomass is used as a substrate. The quadratic effect of temperature was the most significant, followed by the quadratic effect of initial pH and the linear effect of cellobiose concentration. The results corroborated the validity and effectiveness of the model.

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Ouwerkerk, Diane, Anita Maguire, Jenny Gravel, Cathy Minchin, Michael Gravel, Athol Klieve, and Ros Gilbert. "Effect of Feeding Different Cultivars of Leucaena leucocephala on Rumen-Based in vitro Anaerobic Fermentations." Proceedings 36, no. 1 (February 13, 2020): 96. http://dx.doi.org/10.3390/proceedings2019036096.

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The leguminous forage shrub, Leucaena leucocephala, is one of the few nutritional options available to significantly improve beef productivity in Northern Australia. A mixed bacterial rumen inoculum for the detoxification of mimosine (present in Leucaena) and its toxic derivatives 3,4 DHP and 2,3 DHP has been produced in an anaerobic fermenter for the last 23 years by the Queensland Department of Agriculture and Fisheries, using the commercial cultivar Cunninghamii. The development and release of a new psyllid-resistant cultivar ‘Redlands’, offers potential for increasing uptake by the beef industry but brings unanswered questions about its impact on the survival of the toxin degrading bacteria Synergistes jonesii and the overall efficacy of the current inoculum. A series of 30-day anaerobic fermentations were undertaken using the same starter cultures used in the production of commercial inoculum but fed daily with one of three Leucaena cultivars: Cunninghamii, Redlands or Wondergraze. Populations of S. jonesii were monitored daily using a quantitative PCR assay and the ability of the fermentation to detoxify mimosine and its derivatives were assayed on days 10, 15, 20, 25 and 30. Feeding the new Redlands cultivar had a negative impact on S. jonesii numbers and the ability to detoxify 3,4 DHP. However, as fermentation time increased, the S. jonesii populations adapted to the Redlands cultivar. A follow-on fermentation using a starter culture obtained from Day 30 of a Redlands fermentation, showed an immediate increase in S. jonesii populations and was able to detoxify mimosine and its toxic derivatives.

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Arslan, D., K. J. J. Steinbusch, L. Diels, H. V. M. Hamelers, D. P. B. T. B. Strik, C. J. N. Buisman, and H. De Wever. "Selective short-chain carboxylates production: A review of control mechanisms to direct mixed culture fermentations." Critical Reviews in Environmental Science and Technology 46, no. 6 (January 28, 2016): 592–634. http://dx.doi.org/10.1080/10643389.2016.1145959.

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Fancello, Francesco, Angela Bianco, Marta Niccolai, Giacomo Zara, Roberta Coronas, Elisa Serra, Guy D’Hallewin, et al. "Fruit Microbial Communities of the Bisucciu Sardinian Apricot Cultivar (Prunus armeniaca L.) as a Reservoir of New Brewing Starter Strains." Fermentation 8, no. 8 (July 30, 2022): 364. http://dx.doi.org/10.3390/fermentation8080364.

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Local fruit cultivars may improve the originality of specialty beers both directly, by conferring peculiar tastes and flavors, and indirectly, as a reservoir of new starter strains. Accordingly, the fungal and bacterial communities of Bisucciu fruit, a Sardinian apricot cultivar used to produce a local fruit beer, were here investigated by culture-dependent methods. From the 16S rDNA and ITS sequence analyses of 68 epiphytic isolates, 5 bacterial species and 19 fungal species were identified. Aureobasidium pullulans and Rhodotorula glutinis were the dominant fungal species, while Enterococcus mundtii (Firmicutes) and Frigoribacterium faeni (Actinobacteria) were the most represented species among bacterial isolates. Enrichment cultures of fresh apricot puree, followed by fermentation trials in beer wort and beer wort added with apricot puree, allowed the selection of four isolates of Pichia kudriavzevii, Hanseniaspora uvarum, H. pseudoguilliermondii, and H. clermontiae able to dominate over the Bisucciu native microbiota and to produce from 0.57% to 0.74% (vol/vol) of ethanol. HS-SPME-GC/MS analysis highlighted a significant increase in the ester and alcohol fractions as well as a reduction in terpenes after fermentation with the selected yeasts. Results obtained suggest that the yeast isolates may contribute to the definition of the taste and flavor of beers when used in mixed fermentations with Saccharomyces.

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Journal articles on the topic 'Mixed culture fermentations'

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