Dissertations / Theses on the topic 'Biopolymers – Biotechnology'
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Woolnough, Catherine Anne School of Biotechnology & Biomolecular Science UNSW. "Biodegradation, surface rugosities and biofilm coverage of biopolymers." Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Science, 2006. http://handle.unsw.edu.au/1959.4/30426.
Full textOhlhoff, Colin Walter. "Biopolymer gene discovery and characterization using metagenomic libraries." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1801.
Full textChalkiadakis, Eleftherios. "Bio-prospection et biodiversité des micro-organismes des milieux atypiques des lagons de la Nouvelle-Calédonie : Premières évaluations du potentiel de production de nouvelles molécules d’intérêt biotechnologique." Thesis, Nouvelle Calédonie, 2013. http://www.theses.fr/2013NCAL0054/document.
Full textPrevious works on marine bacteria led to the discovery of molecules of great biotechnological interest. Under unusual physical and chemical conditions some microorganisms have developed various survival strategies including exopolysaccharides (EPS) and Poly-3-hydroxyalkanoates (PHAs) production. Due to their many interesting biological, physical and chemical properties, those polymers have found applications in many industrial sectors. Due to interesting physical and chemical properties, EPS can find applications in many industrial sectors including the food industry, cosmetics, for oil and metal recovery from industrial waste and in the mining industry as well. During the last decades EPS have also been demonstrated as interesting bioactive molecules with many applications for human health. PHAs are biopolyesters accumulated as granules in bacteria in order to endure long starving periods. Those biodegradable biopolymers can be used as an alternative to petroleum derived polymers and can be produced from renewable carbon sources. PHAs exhibit a wide variety of properties and structures depending of the carbon source available and the microorganism used for the production. New Caledonia (NC) is frequently referred as a hotspot biodiversity. During a prospection campaign performed in different marine costal ecosystems of NC, a great number (770) of bacteria were isolated from different locations. Screening showed that 55% of the isolates were able to produce under lab conditions EPS and 53% to produce PHA. Partial chemical characterization was performed on purified samples using colorimetric methods, infrared spectrometry (FTIR), gas chromatography (GC) and nuclear magnetic resonance (NMR). Marine bacteria from New Caledonian ecosystems were shown to produce EPS with unusual chemical composition with potential applications in cosmetics. Preliminary experiments also showed high metal-binding capacity with applications in bioremediation. Different PHAs were also produced using different types of sugars and oil as renewable resources. Blue biotechnologies can have various applications in many industrial sectors (Health, food industry, environment, cosmetics etc…) and there is a great international demand for new molecules issue from marine areas. New Caledonian marine bacteria have proved their capacity for producing innovative biopolymers with a wide range of application that can be valuating in on short time period (environment, cosmetics) or at long time (pharmaceutics, surgeries). These applications are promising in order to develop
Rapp, Telana. "Isolation and characterisation of genes encoding biopolymer manufacturing enzymes." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/19968.
Full textENGLISH ABSTRACT: Biopolymers exhibit the required material properties to replace conventional, non-biodegradable, petroleum-based polymer products. They have a closed carbon cycle, making them carbon neutral and environmentally friendly. Biopolymers are produced from non-toxic substrates during in vivo enzymatic reactions. Biosynthesis of the most commercially important biopolymers is too complex to be reproduced in in vitro reactions. Identification of the genes responsible for their biosynthesis has been under investigation, with some pathways already elucidated. The genes involved in the biosynthesis of these polymers have been targeted for genetic manipulation to increase productivity, as well as create tailor-made polymers. Novel biopolymers and the genes responsible for their synthesis are of interest for their potential commercial applications. Bacteria produce a wide range of biopolymers and are being implemented as the bio-factories for biopolymer production. They are capable of utilising easily accessible and renewable carbon sources such as sucrose for polymer biosynthesis. Bacteria thus allow for economical production of these environmentally beneficial polymers. In this study, the gene responsible for the production of an unknown biopolymer from an unknown bacterium was identified. The biopolymer producing bacteria were grown on media enriched with sucrose as carbon source, during an expression library screening in a previous study. Expression library technology was used to search for the gene and it was identified as a 424 amino acid levansucrase which had a 100% homology to Leuconostoc mesenteroides M1FT levansucrase (AAT81165.1). Biopolymer analysis revealed that the biopolymer was a levan, a polysaccharide consisting of only fructose molecules with a molecular weight of ± 5 kDa. Analysis of a 516 bp fragment of the 16S rRNA determined that the unknown bacteria were a Pseudomonas species.
AFRIKAANSE OPSOMMING: Bio-polimere besit noodsaaklike materiële eienskappe wat toelaat dat dit konvensionele, nie bio-afbreekbare, petroleum-gebasseerde polimeer produkte kan vervang. Hulle het n geslote koolstof kringloop en is dus koolstof neutraal en omgewingsvriendelik. Bio-polimere word vervaardig van nie-toksiese substrate, gedurende ensiematiese reaksies in vivo. Die belangrikste kommersiële bio-polimere se ensiematiese produksie is te kompleks om in ʼn in vitro reaksie te herproduseer. Ondersoeke tot die identifikasie van die gene wat verantwoordelik is vir die produksie van die polimere is onderweg, en sommige produksie paaie is reeds bekend. Die bekende gene word geteiken vir genetiese manipulasie om hulle produktiwiteit te vermeerder en om unieke polimere te produseer. Unieke bio-polimere en die gene wat vir hul produksie verantwoordelik is, is van belang vir hulle potentiële implimentering in komersiële toepassings. Bakteria produseer ʼn verskeidenheid bio-polimere en word as die bio-fabrieke vir polimeerproduksie geimplimenteer. Hulle kan maklik bekombare koolstofbronne, soos sukrose, gebruik om bio-polimere te produseer. Bakteria laat dus die ekonomiese produksie van hierdie omgewingsvriendelike polimere toe. In hierdie studie word die geen wat verantwoordelik is vir die produksie van ʼn onbekende bio-polimeer van ʼn onbekende bakteria, geidentifiseer. Die bakteria was gevind op media, wat verryk was met sukrose as koolstofbron, tydens ʼn vorige studie, waartydens ʼn uitdrukkingsbiblioteek gesif was op hierdie media. Uitdrukkingsbiblioteek tegnologie was gebruik om die geen te vind. Die geen was geidentifiseer as ʼn 424 aminosuur, homo-fruktose-polimeer produseerende geen, ʼn “levansucrase”. Die geen het ʼn 100% homologie met die M1FT “levansucrase” geen (AAT81165.1) van Leuconostoc mesenteroides gehad. Analise van die bio-polimeer het bepaal dat die polimeer ʼn polisakkaried was, wat slegs uit fruktose molekules bestaan het. Die molekulêre gewig van die polimeer was ± 5 kDa. Analise van ʼn 516 bp fragment van die 16S rRNS het bepaal dat die bakteria van die Pseudomonas spesie afkomstig was.
Swart, Corne. "Production of libraries to study biopolymer metabolism in Arabidopsis thaliana and Tylosema esculentum." Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85607.
Full textENGLISH ABSTRACT: Biopolymers and bio-degradable polymers are of utmost importance to ensure a sustainable economy. Industry depends on raw material, which in many cases are derived from fossil fuels, but in light of looming energy crises and green revolutions attention is being directed at cellulose and starch biopolymers. This study was therefore set forth to investigate novel genetic key elements of cell wall metabolism in Arabidopsis thaliana and starch synthesis in an under-utilized southern African crop plant, Tylosema esculentum. In the first section of the study a cDNA library of good quality was constructed from regenerating A. thaliana protoplasts as it was expected to be enriching for genes involved in cell wall biosynthesis. Small scale EST sequencing of the library confirmed that a few sequences were similar to genes identified to be highly expressed during protoplast regeneration. The library was to be screened by expression in a microalgae as it is anticipated that cell wall metabolising genes would change the wall structure and visibly alter the colony morphology. An attempt was made at establishing a high-throughput transformation system in the unicellular algae Chlorella protothecoides in which the library was proposed to be screened. Conventional microalgal transformation techniques do not appear to be effective in this strain as the study produced no transgenic algae. Alternative studies into a screening system within another species could still lead to the identification of cell wall biosynthetic genes, which was the first objective in the study. The second objective in the study was to investigate the potential of the orphan crop T. esculentum as starch-producing cash-crop in developing southern African countries. In this section of the study a cDNA library of good quality was produced form the tuber of T. esculentum. The library was transferred to an expression vector and screened functionally in E. coli for the presence of sequences with starch synthase activity. No sequences have been identified yet and screening procedures are still on-going. The starch content in the tuber has also been determined for the first time. The relatively high starch content in combination with low agricultural inputs indicate the potential of the plant as an industrial starch source. Further investigations into the nature of the starch are proposed to identify prospective buyers within the industry.
AFRIKAANSE OPSOMMING: Biopolimere en bio-afbreekbare polimere is van kardinale belang om ‘n volhoubare ekonomie te ontwikkel. Industriële toepassings maak op die oomblik hoofsaaklik staat op fossielbrandstof verwante bronne, maar met die oog op ‘n groen revolusie en energie krissise wat dreig word meer belangstelling getoon in sellulose en stysel biopolimere. Hierdie studie is daarom onderneem om genetiese elemente te identifiseer wat betrokke is by die sintese van die selwand in Arabidopsis thaliana en stysel sintese in die suider Afrikaanse gewas Tylosema esculentum wat grotendeels onderbenut is. In die eerste deel van die studie is ‘n cDNA biblioteek, van goeie kwaliteit, geskep vanuit A. thaliana protoplaste wat besig was om hulle selwande te herbou. Dit word verwag dat die protoplaste gedurende die tydperk aktief besig sal wees om gene uit te druk wat betrokke is by selwandsintese. DNA volgordebepaling het bevestig dat ‘n klein aantal volgordes ooreengestem het met gene wat voorheen gevind was om in ‘n oormaat uitgedruk te word tydens die herbou van protoplas-selwande. Daar was beoog om die biblioteek in ‘n mikroalge uit te druk en sodoende die morfologie op kolonievlak waar te neem vir verandering wat in die selwand meegebring is. Om hierdie rede was die doel om ‘n hoë opbrengs transformasie sisteem te ontwikkel in die mikroalge Chlorella protothecoides. Algemene mikroalge transformasie tegnieke blyk om nie effektief in die spesie te wees nie aangesien geen transgeniese alge waargeneem is nie. Die ontwikkeling van ‘n soortgelyke proses in ‘n ander spesie kan steeds lei na die ontdekking van gene betrokke by selwandsintese in A. thaliana wat die eerste uitkoms van die projek as geheel was. Die tweede uitkoms van die projek was om te ondersoek wat die waarskynlikheid was om T. esculentum te kommersialiseer as ‘n stysel gewas en sodoende ‘n inkomste te skep vir arm boere in ontwikkelende lande in suider Afrika. In hierdie gedeelte van die projek was daar ‘n goeie cDNA biblioteek geskep uit die knol van T. esculentum. Die biblioteek is oorgedra na ‘n plasmied waarop dit aktief uitgedruk kon word in Escherischia coli G6MD2 en daar is gesoek na volgordes wat lei na die sintese van stysel in hierdie bakterieë. Tot op hede is geen sulke volgordes gevind nie, maar die ondersoek gaan steeds voort. Die styselinhoud van die knol is ook vir die eerste keer bepaal in hierdie ondersoek. ‘n Styselinhoud wat relatief hoog is en die lae moeite wat geverg word om die gewas te verbou toon dat die plant potensieel het as ‘n kommersiële bron van stysel. Verdere ondersoeke in die aard van die stysel word ook voorgestel om toekomstige industriële kopers te identifiseer.
Kubo, Tatiana Miyuki Ogawa. "Preparação e caracterização de microparticulas de hialuronato de sodio para encapsulação e liberação controlada de proteinas para aplicação nasal." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267236.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-04T23:14:50Z (GMT). No. of bitstreams: 1 Kubo_TatianaMiyukiOgawa_M.pdf: 3390196 bytes, checksum: 90fbf573dfcb12a87da26f2fdcbfb4dd (MD5) Previous issue date: 2005
Resumo: Neste trabalho foi feito o estudo da preparação de microesferas de hialuronato de sódio pelo método de emulsificação e evaporação de solvente, utilizando temperatura como agente de retificação física. O assunto foi abordado com ênfase na influência das condições operacionais do processo nas propriedades físico-químicas das microesferas e na sua capacidade de incorporação de proteínas, visando atender os requisitos da administração nasal. Inicialmente, a albumina de soro bovino foi usada como proteína modelo e, na segunda etapa, a ovoalbumina foi incorporada nas melhores condições do processo. Para conferir maior resistência mecânica às partículas e prolongar o tempo de liberação da proteína encapsulada, foi utilizado um segundo método de preparação, também por emulsificação, porem com reticulação química feita pela ligação cruzada (crosslinking), com dihidrazida adípica (ADH) em meio aquosos. As microesferas foram caracterizadas pelo seu diâmetro médio e distribuição de tamanhos, morfololgia, cristalinidade, mucoadesividade, intumescimento, eficiência de encapsulação e perfil de liberação das proteínas encapsuladas, eficiência de encapsulação e perfil de liberação das proteínas encapsuladas. Para as partículas reticuladas com ADH, o grau de reticulação foi correlacionado com a sua capacidade de intumescimento e com a cinética de liberação da proteína. Esses efeitos foram caracterizados através do coeficiente de difusão da ovoalbumina nas partículas com diferentes graus de reticulação... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: This work describes the study of sodium hyaluronate microspheres preparation through the emulsification and solvent evaporation technique, using temperature as the physical crosslinking agent. The subject was analyzed with emphasis on the influence of the process operations conditions on the physical and chemical properties of the microspheres and on its protein encapsulation capacity, willing to attend the nasal administration requirements. Initially, bovine serum albumin (BSA) was used as model protein, and in the second step, ovoalbumin (OVA) was incorporated using the best process conditions. In order to improve the mechanical resistance of the particles and extend the release time of the encapsulated protein, a second preparation method, also based on an emulsification but involving a chemical crosslinking reaction using adipic dihidrazide (ADH) in an aqueous solution, was evaluated. The microspheres were characterized by the mean diameter and size distribution, morphology, cristallinity, mucoadhesiveness, swelling capacity, encapsulation efficiency and release profile of the encapsulated proteins. For the particles crosslinked with ADH, the degree of crosslinking was correlated to the swelling capacity and with the protein release kinetics. These effects were characterized by the diffusion coefficient of ovoalbumin from the particles with different crosslinking degrees. The results showed the feasubillity of the sodium hyaluronate microspheres production, its protein encapsulation capability and the flexibility to modulate its properties according to the process conditions... Note: The complete abstract is available with the full electronic digital thesis or dissertations
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestre em Engenharia Química
Matias, Fernanda. "Caracterização de linhagens bacterianas isoladas da biodiversidade brasileira quanto à produção de biopolímeros." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-17042009-145400/.
Full textThe urban waste has been described as one of the largest environmental pollutants. The plastic garbage can represent up to 20% of the volume of household waste. As an alternative to petrochemical plastics, plastic products less damaging to the environment and more biodegradable have been studied, among them polyhydroxyalkanoates (PHA). The PHA is a biodegradable polyester material accumulated as a reserve material by many bacteria and they have very broad commercial applicability. Recently, the actinomycetes have been studied for the production of polymers. In previous work, 53 new strains of actinomycetes producers of polymers were isolated from soil. In this work the bacterial the selection of bacteria was made concerning the polymers production on different carbon. Of the four strains selected, two were analyzed for the production of a new polymer. In the other two strains were amplified and studied the genes of polymers synthases. In all lineages were analyzed taxonomically and in cultivation on industrial waste.
Mello, Karine Gargioni Pereira Correa de. "Síntese e avaliações físico-químicas de quitosanas quimicamente modificadas pela inserção de radicais de anidrido succínico." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9135/tde-19012018-135156/.
Full textThe N-succinil-chitosan is a chemically modified derivative of the biopolymer chitosan. The succinic anhydride attached to the free amino groups presented along the chitosan\'s polymer chain imparts to the molecule different physicochemical properties not exhibited before the modification. These chemical modifications enhance chitosan\'s solubility in slightly acid, neutral and alkaline media. These properties are related to the long alkyllic chains attached to hydrophilic parts. In this case the hydrophilic part of D-¬glucosamine promotes stronger interactions with the water molecules, and consequently, enhances the solubility of the chitosan polymer. It is worthy mentioning that non-modified free chitosan is soluble only in acidic medium (pH ≤5.5).
Rozo, Yeimy Paola Galindo. "Bioprospecção de genes relacionados à biossíntese de polímeros biodegradáveis a partir de uma biblioteca metagenômica de solo de Mata Atlântica." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-30052012-084230/.
Full textTo perform a PHA synthase screening in a metagenomic library from Atlantic forest soil two search methods were applied: phenotypic detection and PCR. Positive results with PCR were obtained by using primers described in the literature and proposed in this study. Amplicons were obtained in 10.67% of the library, 7 of them were sequenced showing similarity with class II and IV phaC genes. In addition, 67 positive clones for class III were obtained and 4 of them were sequenced. Two of these sequences showed high similarity to the glutamine synthase gene type I, the third one showed similarity to the conserved hypothetical protein of the reductase family, and the forth presented similarity to the component D of the hidrogenase-4. According to the results, more specific primers are suggested. Therefore, PCR was more efficient in the detection of PHA biosynthesis genes in the studied metagenomic library.
Borgognoni, Camila Figueiredo. "Microencapsulação por liofilização de D-limoneno em maltodextrina e quitosana modificada." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9133/tde-24012018-093149/.
Full textChitosan is a biopolymer derived from chitin, a component of the shells of crustaceans. It has been of interest due to their broad range of industrial applications. In this study, the chitosan used was chemically modified in order to become water soluble. It was studied the stability of d-limonene emulsion with modified chitosan, flavour retention and release and the hygroscopic behaviour of the microcapsules. The same tests were made with maltodextrin that is a product widely used as a flavour encapsulating agent. The stability of the emulsion was analyzed by spectrofotometry and by headspace/gas chromatography technique. The emulsion characterization was obtained by optical microscopy. Flavour release of microcapsules was measured under different relatives humidities and temperatures. It was observed an improvement on the stability of d-limonene emulsion with modified chitosan along the time and different characteristics in relation to the other. Retention of d-limonene after lyophilization in maltodextrin (40% w/w) was 72% and 62% in modified chitosan (1% w/w). Although, flavour released after encapsulation process in maltodextrin was 72% while in modified chitosan was 50%. Maltodextrin microcapsules presented structural collapse in 90% of relative humidity. The humidity monolayers decreased with temperature increasing for both microcapsules. The heat of sorption for the chitosan microcapsules was greater as well as its diffusivity coefficient. Its pore superficial area was greater. It was observed that chitosan microcapsules absorb water by capilariy absorption. The results suggest that chitosan microcapsules could be a new option of flavour encapsulating agent.
Imran, Muhammad. "Enrobages actifs contenants des peptides antimicrobiens nano-vectorisés." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL026N/document.
Full textFood nanotechnology has the potential to improve food safety and bio-security, food processing, food packaging and functional ingredients. Nano-encapsulation of active agents is an innovative concept to protect them against possible denaturation during processing and storage. The overall objective of the present work was to optimize and develop fluorescent labeling and encapsulation of nisin for molecular transfer study in different packaging based on biopolymers and in the food. Nanoencapsulation of nisin in different nanoliposomes by using continuous cell disruption system (CCDS) has provided an innovative method for nano-delivery systems fabrication. Incorporation of nisin in nano-emulsion form (encapsulated and free) can possibly be an effective approach to control pathogen without compromising the basic physico-chemical attributes of composite HPMC coatings. The fluorescently labeled nisin Z prepared had a molecular weight of 3717.3 Da. Confocal microscopic studies demonstrated the interaction of nisin with the bacterial membranes at the cell-division sites as possible mechanism of action against food borne pathogen. HPMC, CTS, SC and PLA packaging bio-membranes act as a reservoir and progressively release nisin to sustain a constant inhibitory effect. Choice of biopolymer is significant in providing requisite bioavailability of antimicrobial compounds at exterior surface and inside the food system. Based on the present study results, the emerging revolution concerning food safety through packaging possibly will rely on « 3-BIOs » blend with nanotechnology, which refers to Bioactive, Biodegradable and Bio-nanocomposite
Mackay, Stephen. "Identification of the genes encoding enzymes involved in the synthesis of the biopolymer paramylon from Euglena gracilis." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5420.
Full textIncludes bibliography.
Title page: Dept. of Genetics, Faculty of Science
ENGLISH ABSTRACT: Recent advances in medical pharmacology have identified the immune-potentiating effects of β-1,3-glucans on mammalian immune systems. Extensive research has identified and described the mechanisms of action and receptor binding specificity of different β-1,3-glucans as well as their structural and functional relationships. Molecular mass, solubility, structural order, degree of branching as well as chemical modification all determine the effectiveness of the β-1,3-glucan immune-modulating activities, which typically include; macrophage activation, antibody adjuvant activities, reduction of LDL-cholesterol, leukocyte mitogenic activities, cytokine and chemokine production as well as antiviral and antitumor activities. Currently β-1,3-glucans have been sold commercially under the name β-glucan, mostly in the form of Betafectin, a genetically modified yeast derived β-1,3-glucan. Recent studies of different β-1,3-glucans have identified the pharmacological activities of paramylon, a Euglena derived β-1,3-glucan. Although paramylon has relatively low immune-stimulating activities, chemical modification of the paramylon granule increased immune-potentiation with specific antimicrobial and anti-HIV activities. Due to these specific immune-potentiating activities, paramylon is novel in terms of both structure as well as functional activity. In terms of biotechnological application, paramylon is greatly favoured as it is synthesized as an insoluble membrane bound granule in the cytosol of Euglena where most plant and fungal β-1,3-glucan synthases are cell membrane bound highly regulated multifunctional complexes, synthesizing β-1,3-glucan as cell wall components. Due to the novel granular nature of paramylon, expression in other systems with genetic modification could potentially further increase immuno-potentiating activities. In this study, different approaches were attempted in order to identify the genes involved in paramylon synthesis including; constructing and screening a Euglena gracilis cDNA library, sequence analysis of the purified proteins as well as transcription analysis of the sequenced transcriptome and genome of E. gracilis. Putative candidates that encode subunits of the paramylon synthase complex have been identified.
AFRIKAANSE OPSOMMING: Onlangse vordering in mediese farmakologie het die immuun-stimulerende effek van β-1,3-glukane op die soogdier immuunsisteem geïdentifiseer. Intensiewe navorsing het die meganisme van die werking en reseptor bindingspesifisiteit van verskillende β-1,3-glukane, asook hulle struktuur en funksionele verhoudings, geïdentifiseer. Die molekulêre massa, oplosbaarheid, strukturele orientasie, mate van vertakking asook chemiese modifikasies bepaal almal die effektiwiteit van die β-1,3-glukaan immuun-modulerende aktiwiteite. Tipiese immuno-moduleringsaktiwiteite sluit makrofaag aktivering, teenliggaampie adjuvant aktiwiteite, verlaging van LDL-cholesterol, leukosiet mitogeniese aktiwiteite, sitokien en chemokien produksie asook anti-virale en antitumor aktiwiteite in. Huidiglik word β-1,3-glukane onder die naam β-glukaan verkoop meestal in die vorm van Betafectin, ‘n geneties gemodifiseerde gis wat van β-1,3-glukaan afkomstig is. Onlangse studies van verskillende β-1,3-glukane het die farmakologiese aktiwiteit van paramylon, ‘n Euglena afkomstige β-1,3-glukaan geïdentifiseer. Alhoewel paramylon relatiewe lae immuun-stimulerende aktiweite toon, verhoog chemiese modifikasies van die paramylon granules immuun-stimulering, spesifiek die anti-mikrobiese en anti-MIV aktiwiteite. Weens hierdie spesifieke immuun-stimulerende aktiweite, word paramylon as nuut beskou veral in terme van beide struktuur asook funksionele aktiwiteit. In terme van biotegnologiese toepassing, verkry paramylon voorkeur aangesien dit as ‘n onoplosbare membraangebonde granule in die sitosol van Euglena gesintetiseer word terwyl meeste plant en fungus β-1,3-glukaan sintases hoogs gereguleerde multifunksionele selmembraan gebonde komplekse is wat β-1,3-glukaan asook ander selwand komponente sintetiseer. Weens die unieke granulêre natuur van paramylon, sal uitdrukking in ander sisteme ‘n moontlike industrie skep waar deur die transgeniese uitdrukking van granulêre paramylon verdere verbetering van die immuun-stimulerings aktiwiteite kan lei. In hierdie studie is verskillende benaderings aangewend om die gene wat by paramylon sintese betrokke is te identifiseer, dit sluit in die konstruksie en sifting van ‘n E. gracilis cDNS biblioteek, aminosuur volgorde analise van gesuiwerde proteiene asook die transkripsionele analise van die volgorde van die transkriptoom en genoom van E. gracilis. Moontelike kandidate wat vir die subeenhede van die paramylon syntase kompleks kodeer is geïdentifiseer.
Thomas, Tatiana. "Étude du potentiel biotechnologique de Halomonas sp. SF2003 : application à la production de polyhydroxyalcanoates (PHA) Complete genome sequence of the halophilic PHA-producing bacterium Halomonas sp. SF2003: insights into its biotechnological potential PHA Production and PHA Synthases of the Halophilic Bacterium Halomonas sp. SF2003." Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS542.
Full textDepletion of oil ressources coupled to pollution caused by over-exploitation of plastics generate a plentiful of issues and lead to an urgent need for alternatives. PolyHydroxyAlkanoates (PHA) are biopolymers which have distinguished and naturally imposed themselves due to their biosourcing and biodegradability features. Their synthesis by a wide variety of eukaryotic and prokaryotic organisms, from various carbon substrates, makes their production almost unlimited and allows obtaining polymers exposing rigid thermoplastic to elastomeric properties. Despite that, the production yield and the cost are still the main locks to their development. Among possibilities studied, exploitation of marine resources, like halophilic bacteria, arouse a strong interest since adaptability of these strains is extensive and attractive. Halomonas sp. SF2003 is a PHA producing marine bacterium which naturally exposes a considerable versatility in front of carbon substrates and environmental conditions. Characterization and optimization of its PHA production are the main subjects of the presented study. Genome sequencing and annotation, in addition to phenotypic tests, allowed characterization of various genes and metabolic pathways attesting of the adaptative strain character. In the same time, impact of various parameters on Halomonas sp. SF2003 PHA production has been investigated. This work, employing molecular biology and bioprocess tools, will contribute to future development of biotechnological potential of Halomonas sp. SF2003
Arab, Goueini Shahdokht. "Produktion av polyhydroxialkanoater (PHA) med Bacillus megaterium." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26353.
Full textPlastic production and use of plastic are increasing every year throughout the world and this is one of the world's biggest problems. Plastic is a persistent substance, and its biodegradation process can take hundreds of years. This in turn leads to the accumulation of plastic causing harmful effects on the climate, the environment, and people. One of the alternatives that has great potential when it comes to dealing with this problem is to reduce the use of plastics and instead increase the production and use of bioplastics or biopolymers that are biodegradable. Bioplastics have a shorter biodegradation time than plastics and therefore bioplastics are a good alternative instead of using ordinary plastic. There are three different groups of bioplastics, namely those that are bio-based, those that are biodegradable and those that are both bio-based and biodegradable. One type of bioplastic that is biodegradable and bio-based is Polyhydroxyalkanoates (PHA) which are used in various industries as PHA is one of the biopolymers that shows the greatest potential to replace plastic in the future. Research is underway at the University of Borås with the goal of developing a new process for the production and recycling of PHAs. The process is based on the production of PHAs from volatile fatty acids produced from acidogenic fermentation. Acid fermentation is a modified process of anaerobic digestion; the latter is used nowadays to produce biogas from waste and can be the right process for recycling PHA-based waste and for producing a cheap substrate, namely volatile fatty acids for PHA's production. This project is about a part of the process, namely the production of PHAs with bacteria. The research group at the University of Borås has a bacterial strain that has not been yet investigated for the production of PHAs. Before this bacterium can be studied for the production of PHAs from volatile fatty acids the compositionoptimization of the cultivation medium for bacterial growth is needed. The purpose of this work is to investigate the effect of different glucose concentrations as a source of carbon and different amounts of ammonium sulphate in the growth of the bacterium Bacillus megaterium and the production of polyhydroxyalkanoates. A comparison between the defined medium under development in this project with nutrient broth, a complex medium normally used to grow bacteria, was also carried out in order to evaluate the suitability of the defined medium to support bacterial growth. During this work several different analytical techniques have been used such as pH measurement, High-Performance Liquid Chromatography (HPLC), Spectrometer (for optical density (OD) measurement), and Fourier-Transform Infrared Spectroscopy (FTIR) to evaluate bacterial growth and production of PHA as well as PHAs composition. The amount of ammonium sulphate affected glucose consumption rate, where concentrations of 3 g/L and 7 g/L were shown to lead to a faster glucose consumption compared to that at 5 g/L. Therefore, 3 g/L ammonium sulphate was chosen as it represents less chemical consumption while not affecting cell growth negatively. During bacterial cultivation in a medium containing 3 g/L ammonium sulphate, 10 g/L glucose, among other compounds, glucose was completely consumed after 72 hours of bacterial growth and the maximum PHA production was 13-14% based on cell dry weight. The cultivation medium developed in this project was shown to be suitable for bacterial growth since the use of nutrient broth, normally used for bacterial growth, led to slower glucose consumption. Initial glucose concentration (5, 10 and 20 g/L) did not affect glucose consumption rate and should be further studied to increase cell concentration and consequently the production of PHA. One of the most studied polymers in the PHA family is polyhydroxybutyrate (PHB). During this work, it was found, through the use of FTIR, that PHB was produced.
Cicéron, Félix. "Caractérisation de la fucosyltransférase du xyloglucane d'Arabidopsis thaliana « AtFuT1 » : étude biochimique et structurale." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV020/document.
Full textFucosyltransferases are enzymes that transfer a fucose residue from GDP-fucose on varied acceptors (oligosaccharides, proteins). In Human, these glycosyltransferases are involved in many biological and pathological processes. Numerous fucosyltransferase exist in the plant kingdom. Among them, FuT1 transfers a fucose linked in 1,2 onto a galactose of xyloglucan: a major hemicellulose of dicots cell wall. This branched polysaccharide is intensively studied because of its current and potential industrial applications in textile, food, pharmaceuticals, etc. The main objective of this PhD program was to obtain biochemical and structural information on the fucosyltransferase AtFuT1 from the model plant Arabidopsis thaliana. A recombinant form of this protein has therefore been produced, using the baculovirus/insect cell system. In order to get sufficient amount of protein for structural studies, a suspension cell culture method has been set-up in the lab. A two-step purification protocol, involving affinity and size exclusion chromatography was established. The active, and highly pure recovered protein was used to determine the biochemical properties of the protein towards its substrates (GDP-fucose and xyloglucan), to get protein crystals and hence to solve its 3D structure in complex with GDP and a xyloglucan derived oligosaccharide (2.2 Å resolution). AtFuT1 behaves in solution and in crystallo as a non-covalent dimer. The protein adopts a variant of the classical GTB fold. In addition, novel glycosyltransferase assay have been designed allowing the screening of numerous reaction conditions. Methods and techniques that were developed during this study should be a useful base for the characterization of other glycosyltransferase
Al, Mallah Maha. "Biodegradation des hydrocarbures dans les milieux sursales." Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX22040.
Full textGrousseau, Estelle. "Potentialités de production de Poly-Hydroxy-Alcanoates (PHA) chez Cupriavidus necator sur substrats de type acides gras volatifs : études cinétiques et métaboliques." Thesis, Toulouse, INSA, 2012. http://www.theses.fr/2012ISAT0002/document.
Full textReserve Biopolymer (PolyHydroxyAlkanoates or PHA) accumulation by the strain Cupriavidus necator, from Volatile Fatty Acids (VFA, like butyric acid, propionic acid and acetic acid) was investigated. This production is induced by a phosphorus limitation. For this type of substrates, performances reached during cultures are among the best listed in the literature: up to 66 g.L-1 of total biomass with 88% (w/w) of PHB –PolyHydroxyButyrate- or PHB-co-HV -PolyHydroxyButyrate-co-HydroxyValerate- with a HV content up to 52 Mole%.For each carbon source, kinetic and stoechiometric characterization has been carried out thanks to Fed-Batch cultures with non-limiting and non-inhibitory carbon feed. It has been established:- a maximal growth rate of 0,33 h-1 for the three acid investigated- a relationship between specific PHA production rate and growth rate which is set by the availability and production flux of NADPH2. For growth rate above 0,05 h-1, there is an inverse coupling. For growth rate under 0,05 h-1, there is a partial coupling.- an optimum of 0,35 Cmole.Cmole-1.h-1 is associated with a growth rate of 0,05 h-1.- if a low residual growth rate is maintained, an improvement of PHB production is recorded in terms of specific production rate and yieldsThe response of the strain to an excess of acid substrate was characterized through the investigation of transient state induced by pulsed addition of substrate during continuous cultures stabilized in steady state. It was shown that in excess of phosphorus, when there is a substrate excess, the strain is unable to quickly adapt its growth rate, so the excess is directed to PHA production whose ways seem to be more easily mobilized. Under phosphorus limitation, an excess of substrate is used for PHA production. Acid inhibition results in a decrease in biomass and PHA production capacity which leads to a decrease in carbon assimilation and conversion yields. The sensitivity of a continuous system to an excess of substrate depends on the chosen operating point: the more it is optimal in terms of specific production rate, the less the system is robust. Propionic acid is highly inhibitory compared to the other acids studied (from 3-4 mM versus 30-40 mM). It does not act only via an excessive accumulation in the cytoplasm but also exerts a specific inhibition of metabolic pathways.An antagonism between substrates (acetic and butyric acid) has been established and explained thanks to the Metabolic Flux Analysis. Acetic acid is preferentially used to produce biomass, energy and cofactors for PHA synthesis, whereas butyric acid is used to product PHB. According to the conditions set during steady state, maximal content of acetic acid admitted in the feed can be calculated. It can be limited to 40% of the carbon in the feed.Finally if a growth rate is maintained thanks to a phosphorus supply, the maximal HV content in polymer is function of propionic acid in the feed and cannot exceed 33 ± 5 Mole% on pure propionic acid. Conversely, if there is no residual growth, a total conversion of propionic acid into HV is allowed
Khan, Faez Iqbal. "Experimental and computational studies of a fungal chitinase." Thesis, 2015. http://hdl.handle.net/10321/1267.
Full textChitin, the second most abundant natural biopolymer, is composed of repeating units of N-acetyl-β-D-glucosamine and primarily forms the structural component of protective biological matrices such as fungal cell walls and exoskeletons of insects. Chitinases are a ubiquitous class of extracellular enzymes that have gained attention in the past few years due to their wide range of biotechnological applications, especially in the field of agriculture for bio-control of fungal phytopathogens. They play an important role in the defense of organisms against chitin-containing parasites by hydrolyzing the β-1,4-linkages in chitin and hence act as anti-fungal as well as anti-biofouling agents. Moreover, the effectiveness of conventional insecticides is increasingly compromised by the occurrence of resistance and thus, chitinases offer a potential alternative to the use of chemical fungicides. In recent years, thermostable enzymes isolated from thermophilic microorganisms have gained widespread attention in industrial, medical, environmental and biotechnological applications due to their inherent stability at high temperatures and a wide range of pH optima. Determination of the three- dimensional structure of a protein can provide important details about its biological functions and its mode of action. However, despite their significance, the precise three-dimensional structures of most of the chitinases, including those isolated from Thermomyces lanuginosus is not fully characterized so far. Hence, the main focus of the present study was to gain a better understanding of the structural features of chitinases obtained from this thermostable fungus using both experimental and computational techniques, and their relationship with their activity profiles. The genes encoding thermostable chitinase II from T. lanuginosus were isolated and cloned in both E. coli as well as the Pichia pastoris expression system. Analysis of the nucleotide sequences revealed that the chitinase II gene (1196 bp) encodes a 343 amino acid protein of molecular weight 36.65 kDa whereas the chitinase I gene (1538 bp) encodes a 400 amino acid protein of molecular weight 44.14 kDa. In silico protein modeling was helpful in predicting the 3D models of the novel chitinase II enzyme, followed by the prediction of its active sites. The presence of Glu176 was found to be essential for the activity of chitinase II. Similarly, analysis of chitinase I revealed several active sites in its structural framework. A 10 ns Molecular dynamics (MD) simulations was implemented to assess the conformational preferences of chitinases. The MD trajectories at different temperatures clearly revealed that the stability of the enzymes were maintained at higher temperatures. Additionally, a constant pH molecular dynamics simulations at a pH range 2-6 was performed to establish the optimum activity and stability profiles of chitinase I and chitinase II. For this purpose, the Molecular Dynamics simulations were carried out at fixed protonation states in an explicit water environment to evaluate the effect of the physiological pH on chitinase I and II enzymes obtained from T. lanuginosus. The results suggest a strong conformational pH dependence of chitinases. These enzymes retained their characteristic TIM Barrel fold at the respective protonated conditions, thus validated the experimental outcomes. Further, the different stability and flexibility predictions were used to assess the relation of point mutations and enzyme stabilities. Our results pave the way to engineer new and better thermostable enzymes.
Cabral, Diogo José Rebelo. "Estabilização de um solo com recurso a biopolímeros: Efeito da dosagem e do tempo de cura." Master's thesis, 2020. http://hdl.handle.net/10316/90203.
Full textNa área da Engenharia Civil, mais concretamente no ramo da geotecnia, a procura e o estudo de técnicas sustentáveis tem vindo a aumentar, visando substituir técnicas que afectam negativamente o ambiente. Neste contexto, o presente trabalho pretende contribuir para a afirmação de técnicas amigas do ambiente como a bioestabilização com recurso ao Xantano, analisando o efeito do tempo de cura e da dosagem do biopolímero no comportamento em condições confinadas e não confinadas. Inicialmente, de modo a classificar o solo efectuou-se a sua caracterização geotécnica, tendo sido necessário avaliar vários parâmetros, tais como: a sua composição granulométrica, os limites de consistência, a densidade das partículas do solo, o teor de água óptimo e peso volúmico seco máximo obtido do Ensaio Proctor e o valor do pH do solo natural. Numa fase posterior, procedeu-se à determinação da resistência à compressão não confinada e ao módulo de deformabilidade através de ensaios UCS, bem como as medições dos valores do pH e dos teores de humidade dos provetes bioestabilizados. Para o estudo da compressibilidade do solo em condições confinadas, recorreu-se a ensaios edométricos para analisar o índice de compressibilidade, o índice de recompressibilidade/ expansibilidade, a tensão de pré-consolidação e também o coeficiente de consolidação. Complementarmente, realizaram-se ensaios SEM (Scanning Electron Microscops) com o intuito de analisar o efeito do Xantano na estrutura do solo estabilizado.Após a conclusão do presente trabalho, verificou-se que o processo de bioestabilização no solo em estudo proporciona, de maneira geral, um melhoramento da resistência. Por outro lado, não parece ter efeitos benéficos na compressibilidade do solo.
In the Civil Engineering area, more concretly in the geotechnical branch, the search and studies of sustainable techniques has been increasing, aiming to replace the techniques that affect the ambient negatively. In this context, the current work intends to contribute to the affirmation of techniques environmentally friendly as the biostabilization through the use of Xanthan Gum, analyzing the effect of the curing time and the content of the biopolymer on the behavior in confined and not confined conditions. Initially, to classify the soil was made its geotechnical caracterization, and for that was evaluated several parameters, such as: the size granulometric distribution, the consistency limits, the soil particle density, the optimum water content and the maximum volumetric weight calculated by the Proctor Test, and the pH value of the natural soil. In the next phase of this work, it was evaluated the unconfined compression strength and the deformability modulus by using UCS tests, as well as the values of the pH and the water content of the biostabilizated samples. To study the compressibility of the soil in confined conditions, it was done an odoemetric test to evaluate the compression index, recompression/ swelling index, the preconsolidation-stress and also the coefficient of consolidation. Complemently, SEM Tests were made in order to analyze the effect of Xanthan Gum in the structure of the stabilized soil.After the conclusion of the current work, it was found that the process of biostabilization in the soil in study provides, in general, an improvement of the resistance. On the other hand, it doesn´t seem to have a benefic effect on the soil compressibility.
Jahns, Anika Carolin. "Towards a better understanding of the polyhydroxyalkanoate synthase from Ralstonia eutropha : protein engineering and molecular biometrics : a thesis presented to Massey University in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Microbiology." 2009. http://hdl.handle.net/10179/1081.
Full textTanataweethum, Nida. "Mechanical property and biocompatibility of PLLA coated DCPD composite scaffolds." Thesis, 2014. http://hdl.handle.net/1805/4448.
Full textDicalcium phosphate dihydrate (DCPD) cements have been used for bone repair due to its excellent biocompatibility and resorbability. However, DCPD cements are typically weak and brittle. To overcome these limitations, the sodium citrate used as a setting regulator and the coating of poly-L-lactide acid (PLLA) technique have been proposed in this study. The first purpose of this thesis is to develop composite PLLA/DCPD scaffolds with enhanced toughness by PLLA coating. The second purpose is to examine the biocompatibility of the scaffolds. The final purpose is to investigate the degradation behaviors of DCPD and PLLA/DCPD scaffolds. In this experiment, DCPD cements were synthesized from monocalcium phosphate monohydrate (MCPM) and 𝛽-tricalcium phosphate (𝛽 –TCP) by using deionized water and sodium citrate as liquid components. The samples were prepared with powder to liquid ratio (P/L) at 1.00, 1.25 and 1.50. To fabricate the PLLA/DCPD composite samples, DCPD samples were coated with 5 % PLLA. The samples were characterized mechanical properties, such as porosity, diametral tensile strength, and fracture energy. The mechanical properties of DCPD scaffolds with and without PLLA coating after the in vitro static degradation (day 1, week1, 4, and 6) and in vitro dynamic degradation (day 1, week 1, 2, 4, 6, and 8) were investigated by measuring their weight loss, fracture energy, and pH of phosphate buffer solution. In addition, the dog bone marrow stromal stem cells (dBMSCs) adhesion on DCPD and PLLA/DCPD composite samples were examined by scanning electron microscopy. The cell proliferation and differentiation in the medium conditioned with DCPD and PLLA/DCPD composite samples were studied by XTT (2,3-Bis(2-methoxy-4- nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt), and alkaline phosphatase (ALP) assay, respectively. The addition of sodium citrate and PLLA coating played a crucial role in improving the mechanical properties of the samples by increasing the diametral tensile strength from 0.50 ± 0.15 MPa to 2.70 ± 0.54 MPa and increasing the fracture energy from 0.76 ± 0.18 N-mm to 12.67 ± 4.97 N-mm. The DCPD and PLLA/DCPD composite samples were compatible with dBMSCs and the cells were able to proliferate and differentiate in the conditioned medium. The degradation rate of DCPD and PLLA/DCPD samples were not significant different (p > 0.05). However, the DCPD and PLLA/DCPD composite samples those used sodium citrate as a liquid component was found to degrade faster than the groups that use deionized water as liquid component