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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Isolation and characterisation of esterases from thermophilic Actinomyces

Oldale, Megan January 2010 (has links)
<p>Alternative sources of fuel are required worldwide, and bio-ethanol is the leading candidate. Lignocellulosic biomass, a waste component of the agricultural industry, is a promising renewable source. Due to its complex structure it is highly recalcitrant, requiring the synergistic action of a battery of enzymes to achieve complete digestion. These enzymes include cellulases, hemicellulase and the accessory enzymes acetyl xylan esterase (AXE) and ferulic acid esterase (FAE). Thermpohilic Actinomyces isolates with the ability to hydrolyze xylan were screened for esterase activity. Two isolates (ORS10 and GSIV1), identified as Streptomyces spp, were positive for AXE activity. A cosmid library representative of isolate ORS10 was composed and screened for AXE activity using -naphthyl acetate as substrate. An 18 kb cosmid clone, 18D7, tested positive for AXE activity. Intracellular fractions extracted from ORS10 were precipitated with ammonium sulphate and partially purified 161-fold. Specific activity was measured after dialysis and ion-exchange chromatography. Overall yield of the partially purified enzyme was 34 %. Two protein bands of molecular masses 40 kDa and 60 kDa have been subjected to trypsin digestion and MALDI-TOF mass spectrometry analysis. The partially purified AXE displayed optimum activity at pH 9 and at 50&deg / C. AXE activity was stable for at least 1.5 hours between 30&deg / C and 40&deg / C, and for 24 hours between pH 6-9. The kM and Vmax values were 16.93 mg/ml and 1645 units/mg enzyme, respectively. The stability of the partially purified AXE at 30&deg / C-40&deg / C suggests potential for industrial applications that utilise mesophilic fermentations.</p>
2

Isolation and characterisation of esterases from thermophilic Actinomyces

Oldale, Megan January 2010 (has links)
<p>Alternative sources of fuel are required worldwide, and bio-ethanol is the leading candidate. Lignocellulosic biomass, a waste component of the agricultural industry, is a promising renewable source. Due to its complex structure it is highly recalcitrant, requiring the synergistic action of a battery of enzymes to achieve complete digestion. These enzymes include cellulases, hemicellulase and the accessory enzymes acetyl xylan esterase (AXE) and ferulic acid esterase (FAE). Thermpohilic Actinomyces isolates with the ability to hydrolyze xylan were screened for esterase activity. Two isolates (ORS10 and GSIV1), identified as Streptomyces spp, were positive for AXE activity. A cosmid library representative of isolate ORS10 was composed and screened for AXE activity using -naphthyl acetate as substrate. An 18 kb cosmid clone, 18D7, tested positive for AXE activity. Intracellular fractions extracted from ORS10 were precipitated with ammonium sulphate and partially purified 161-fold. Specific activity was measured after dialysis and ion-exchange chromatography. Overall yield of the partially purified enzyme was 34 %. Two protein bands of molecular masses 40 kDa and 60 kDa have been subjected to trypsin digestion and MALDI-TOF mass spectrometry analysis. The partially purified AXE displayed optimum activity at pH 9 and at 50&deg / C. AXE activity was stable for at least 1.5 hours between 30&deg / C and 40&deg / C, and for 24 hours between pH 6-9. The kM and Vmax values were 16.93 mg/ml and 1645 units/mg enzyme, respectively. The stability of the partially purified AXE at 30&deg / C-40&deg / C suggests potential for industrial applications that utilise mesophilic fermentations.</p>
3

Isolation and characterisation of esterases from thermophilic Actinomyces

Oldale, Megan January 2010 (has links)
Magister Scientiae - MSc / Alternative sources of fuel are required worldwide, and bio-ethanol is the leading candidate. Lignocellulosic biomass, a waste component of the agricultural industry, is a promising renewable source. Due to its complex structure it is highly recalcitrant, requiring the synergistic action of a battery of enzymes to achieve complete digestion. These enzymes include cellulases, hemicellulase and the accessory enzymes acetyl xylan esterase (AXE) and ferulic acid esterase (FAE). Thermpohilic Actinomyces isolates with the ability to hydrolyze xylan were screened for esterase activity. Two isolates (ORS10 and GSIV1), identified as Streptomyces spp, were positive for AXE activity. A cosmid library representative of isolate ORS10 was composed and screened for AXE activity using -naphthyl acetate as substrate. An 18 kb cosmid clone, 18D7, tested positive for AXE activity. Intracellular fractions extracted from ORS10 were precipitated with ammonium sulphate and partially purified 161-fold. Specific activity was measured after dialysis and ion-exchange chromatography. Overall yield of the partially purified enzyme was 34 %. Two protein bands of molecular masses 40 kDa and 60 kDa have been subjected to trypsin digestion and MALDI-TOF mass spectrometry analysis. The partially purified AXE displayed optimum activity at pH 9 and at 50°C. AXE activity was stable for at least 1.5 hours between 30°C and 40°C, and for 24 hours between pH 6-9. The kM and Vmax values were 16.93 mg/ml and 1645 units/mg enzyme, respectively. The stability of the partially purified AXE at 30°C-40°C suggests potential for industrial applications that utilise mesophilic fermentations. / South Africa
4

Development of a flat sheet woven fabric membrane fermenter for xylanase production by Thermomyces lanuginosus

Thorulsley, Venessa January 2015 (has links)
Submitted in fulfilment of the requirements for the degree of Master of Engineering, Durban University of Technology, Durban, South Africa, 2015. / Fermentation processes are vital for the production of numerous bioproducts. Fermentation being the mass culture of micro – organisms for the production of some desired product, is an extensive field, with immense prospects for study and improvement. Enzyme production is of significance as these proteins are biological catalysts, finding niches in numerous industries, xylanase for example is utilized in the pulp and paper, animal feed, biofuel and food production processes. During enzyme production, a critical step is biomass separation, whereby the valuable product, the enzyme, is removed from the broth or micro – biological culture before it is denatured. This is typically achieved via centrifugation. The aim of this study was to develop and evaluate a submerged membrane fermenter system with the specific outcome of increasing the rate of production of xylanase, from the thermophilic fungal species Thermomyces lanuginous DSM 5826. Preliminary shake flask experiments were performed to determine the optimal production conditions, followed by partial characterization of the enzyme. A bioreactor was then fabricated to include a flat sheet membrane module, with outlets for permeate and broth withdrawal and inlets for feed and sterile air input. Experiments were conducted to determine the optimal dilution rate for maximum volumetric productivity. Results from the shake flask experiments indicated that the best conditions for xylanase production, yielding xylanase activity of 5118.60 ± 42.76 U.mL-1 was using nutrient medium containing beechwood xylan (1.5 % w/v), yeast extract (1.5 % w/v), potassium dihydrogen phosphate (0.5 % w/v), adjusted to a pH of 6.5 and inoculated with 1.0 mL of spore solution, rotating in a shaking incubator set to 150 rpm at 50 °C. Apart from analysis of the effect of the carbon source on xylanase activity, coarse corn cobs were used in the shake flask experiments as a cost saving initiative. The pH optima was determined to be 6.5 while the temperature optima of the enzyme was 70 °C. SDS PAGE analysis revealed that the molecular weight of the enzyme was between 25 and 35 kDa and qualitative analysis via a zymogram revealed clear zones of hydrolysis on a xylan infused agarose gel. During short run membrane fermenter experiments the percentage increase in enzyme activity between the batch operation (610.58 ± 34.54 U.mL-1) and semi – continuous operation (981.73 ± 55.54 U.mL-1) with beechwood xylan nutrient replenishment was 60.78 %. The maximum volumetric productivity achieved with beechwood supplementation after 192 hours in semi – continuous operation (5.32 ± 0.30 U.mL-1.hr-1) was 2.1 times greater than that of batch operation (2.54 ± 0.14 U.mL-1.hr-1) which equates to an increase of 110.28 % in productivity measured at its peak. The increase in total activity between batch (610 576.92 U) and beechwood xylan medium supplemented semi – continuous mode (1 184 937.50 U) resulted in a 94.07 % increase. During long run experimental periods, the increase in production of xylanase between the batch (873.26 ± 61.78 U.mL-1) and the xylan medium membrane system (1522.41 ± 107.65 U.mL-1) was determined to be 74.34 % while an overall average increase in productivity between the batch and xylan fed membrane system was 43.25%. The total enzyme activity with in membrane mode with beechwood xylan nutrient medium feed was 160 % greater than the batch process offering a 2.6 – fold increase. Experiments where de – ionized water was alternated with beechwood xylan nutrient medium had no significant impact on the productivity or enzyme activity. The optimal dilution rate for maximum volumetric productivity as determined to be 0.0033 hr-1. The results are indicative of the potential viability of such a design, yielding the desired outcome of a membrane integrated system to significantly increase the production of enzymes during fermentation.
5

Isolamento e seleção de fungos filamentosos termofílicos produtores de celulases, xilanases e celobiose desidrogenase com potencial para sacarificação do bagaço de cana-de-açúcar

Rosa, Isabel Zaparoli [UNESP] 13 June 2014 (has links) (PDF)
Made available in DSpace on 2014-11-10T11:09:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-13Bitstream added on 2014-11-10T11:57:42Z : No. of bitstreams: 1 000790107_20150511.pdf: 338150 bytes, checksum: a68b2a9eb314d27a58d6c9cc6e3d1e9c (MD5) Bitstreams deleted on 2015-05-11T13:13:25Z: 000790107_20150511.pdf,Bitstream added on 2015-05-11T13:13:55Z : No. of bitstreams: 1 000790107.pdf: 1190313 bytes, checksum: 3985054a66230646f5c4ccfafc0565a2 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Devido à crescente demanda por combustíveis, pesquisas vêm sendo desenvolvidas com o intuito de se obterem novos tipos de biocombustíveis provenientes de fontes renováveis. O etanol celulósico tem sido cogitado como complemento da produção de etanol, entretanto, a viabilização desse processo requer o desenvolvimento de tecnologias de sacarificação dos materiais lignocelulósicos, por via bioquímica, como a enzimática, ou por métodos abióticos. Os fungos filamentosos são um grupo de microrganismos secretores de enzimas que atuam na degradação de biomassa. As enzimas do complexo celulolítico e hemicelulolítico clivam as ligações que formam os polímeros de polissacarídeos liberando hexoses e pentoses fermentescíveis a etanol, porém, enzimas acessórias como a celobiose desidrogenase, são importantes na eficiência do processo. O presente projeto visou o isolamento de cepas fúngicas termofílicas com habilidade de secretar aquelas enzimas, assim como, a obtenção de preparados enzimáticos com estabilidade às variações de temperatura e pH que ocorrem durante as etapas da hidrólise. Foram isoladas 32 linhagens de fungos capazes de crescer em temperaturas entre 45 e 60ºC, tendo sido selecionadas cinco para as etapas seguintes do trabalho (Thermomyces lanuginosus S1, T. lanuginosus S3, Rasamsonia emersonii S10, T. lanuginosus FZI e R. emersonii BC) em função de apresentarem crescimento a 60ºC. Entre essas linhagens, as maiores atividades de β-glicosidase (52 U/g) e endoglucanase (579 U/g) foram obtidas em meio de cultivo da cepa R. emersonii S10 em 240h para ambas as enzimas. A melhor atividade de FPase foi apresentada pelo fungo T. lanuginosus S1 em 168h de cultivo, tendo produzido 262,8 U/g da enzima. O fungo R. emersonii S10 foi o único que apresentou a produção detectável das enzimas avicelase (9,2 U/g) e β-xilosidase (910,7 U/g). Esse isolado também produziu as maiores atividades de xilanase com ... / Owing the growing demand for fuels, research is being done with the aim of obtaining new types of biofuels from renewable resources. Cellulosic ethanol, obtained from residual biomass from agricultural and agro-industrial processes has been considered as a complement of ethanol production by decreasing the need for expansion of sugarcane areas. However, the viability of the process requires the development of technologies saccharification of lignocellulosic materials by biochemical route, such as enzymatic or abiotic methods. The filamentous fungi are a group of microorganisms that produce (secretory) of enzymes involved in the degradation of biomass. The enzymes cleave hemicellulolytic and cellulolytic complex connections that form polymers of polysaccharides present in the biomass releasing fermentable hexoses and pentoses to ethanol, however, accessory enzymes such as cellobiose dehydrogenase are important in the process efficiency. This design aimed at the isolation of thermophilic fungal strains with the ability to secrete those enzymes, as well as the enzyme preparations to obtain stability to pH and temperature variations that occur during the hydrolysis step. 32 fungal strains capable of growing at temperatures between 45 and 60 °C were isolated, five were selected to continue the following work steps (Thermomyces lanuginosus S1, T. lanuginosus S3, Rasamsonia emersonii S10, R. emersonii BC and T. lanuginosus FZI) as a function of experiencing growth at 60 °C. Among these strains, the highest activities of β-glucosidase (52 U/g) and endoglucanase (579 U/g) were obtained from the culture medium of strain R. emersonii S10 in 240h for both enzymes. The best activity FPase (cellulase that hydrolyzes filter paper) was presented by the fungus T. lanuginosus S1 in 168h of cultivation, having produced 262.8 U/g enzyme. The R. emersonii S10 was the only fungus that showed detectable avicelase production of enzymes (9.2 U/g) and ...
6

Isolamento e seleção de fungos filamentosos termofílicos produtores de celulases, xilanases e celobiose desidrogenase com potencial para sacarificação do bagaço de cana-de-açúcar /

Rosa, Isabel Zaparoli. January 2014 (has links)
Orientador: Eleni Gomes / Banca: Adalberto Pessoa Júnior / Banca: Gustavo O. Bonilla / Resumo: Devido à crescente demanda por combustíveis, pesquisas vêm sendo desenvolvidas com o intuito de se obterem novos tipos de biocombustíveis provenientes de fontes renováveis. O etanol celulósico tem sido cogitado como complemento da produção de etanol, entretanto, a viabilização desse processo requer o desenvolvimento de tecnologias de sacarificação dos materiais lignocelulósicos, por via bioquímica, como a enzimática, ou por métodos abióticos. Os fungos filamentosos são um grupo de microrganismos secretores de enzimas que atuam na degradação de biomassa. As enzimas do complexo celulolítico e hemicelulolítico clivam as ligações que formam os polímeros de polissacarídeos liberando hexoses e pentoses fermentescíveis a etanol, porém, enzimas acessórias como a celobiose desidrogenase, são importantes na eficiência do processo. O presente projeto visou o isolamento de cepas fúngicas termofílicas com habilidade de secretar aquelas enzimas, assim como, a obtenção de preparados enzimáticos com estabilidade às variações de temperatura e pH que ocorrem durante as etapas da hidrólise. Foram isoladas 32 linhagens de fungos capazes de crescer em temperaturas entre 45 e 60ºC, tendo sido selecionadas cinco para as etapas seguintes do trabalho (Thermomyces lanuginosus S1, T. lanuginosus S3, Rasamsonia emersonii S10, T. lanuginosus FZI e R. emersonii BC) em função de apresentarem crescimento a 60ºC. Entre essas linhagens, as maiores atividades de β-glicosidase (52 U/g) e endoglucanase (579 U/g) foram obtidas em meio de cultivo da cepa R. emersonii S10 em 240h para ambas as enzimas. A melhor atividade de FPase foi apresentada pelo fungo T. lanuginosus S1 em 168h de cultivo, tendo produzido 262,8 U/g da enzima. O fungo R. emersonii S10 foi o único que apresentou a produção detectável das enzimas avicelase (9,2 U/g) e β-xilosidase (910,7 U/g). Esse isolado também produziu as maiores atividades de xilanase com ... / Abstract: Owing the growing demand for fuels, research is being done with the aim of obtaining new types of biofuels from renewable resources. Cellulosic ethanol, obtained from residual biomass from agricultural and agro-industrial processes has been considered as a complement of ethanol production by decreasing the need for expansion of sugarcane areas. However, the viability of the process requires the development of technologies saccharification of lignocellulosic materials by biochemical route, such as enzymatic or abiotic methods. The filamentous fungi are a group of microorganisms that produce (secretory) of enzymes involved in the degradation of biomass. The enzymes cleave hemicellulolytic and cellulolytic complex connections that form polymers of polysaccharides present in the biomass releasing fermentable hexoses and pentoses to ethanol, however, accessory enzymes such as cellobiose dehydrogenase are important in the process efficiency. This design aimed at the isolation of thermophilic fungal strains with the ability to secrete those enzymes, as well as the enzyme preparations to obtain stability to pH and temperature variations that occur during the hydrolysis step. 32 fungal strains capable of growing at temperatures between 45 and 60 °C were isolated, five were selected to continue the following work steps (Thermomyces lanuginosus S1, T. lanuginosus S3, Rasamsonia emersonii S10, R. emersonii BC and T. lanuginosus FZI) as a function of experiencing growth at 60 °C. Among these strains, the highest activities of β-glucosidase (52 U/g) and endoglucanase (579 U/g) were obtained from the culture medium of strain R. emersonii S10 in 240h for both enzymes. The best activity FPase (cellulase that hydrolyzes filter paper) was presented by the fungus T. lanuginosus S1 in 168h of cultivation, having produced 262.8 U/g enzyme. The R. emersonii S10 was the only fungus that showed detectable avicelase production of enzymes (9.2 U/g) and ... / Mestre
7

Xylanase hyper-producer : the genome of the thermophilic fungus Thermomyces lanuginosus

Mchunu, Nokuthula Peace 08 August 2014 (has links)
Submitted in complete fulfillment of the requirements for the Degree of Doctor of Technology: Biotechnology, Durban University of Technology, Durban, South Africa. 2014. / The global demand for green technology has created a need to search for microbes that can play an active role in advancing a greener and cleaner future. Microbial enzymes are nature’s keys to life and their efficiency, specificity and environmental-friendliness has lead to their increased use in industrial processes. Thermomyces lanuginosus is a thermophilic fungus that can degrade plant biomass and produces a variety of enzymes that have industrial application. The fungus T. lanuginosus SSBP has been reported in literature to produce the highest level of xylanase among other Thermomyces strains and some of its enzyme s viz., amylase and lipase are already being used. Because of this ability, it has been identified as one of the organisms that can have various industrial applications. Although a few proteins from this fungus have been cloned and used commercially, the vast majority are still unknown. In order to identify new protein candidates and understand their biochemical interactions, the T. lanuginosus genome (DNA) and the transcriptome (mRNA) were sequenced using 454 Roche and Solexa sequencing platforms. Genome and transcriptome data was assembled using Newbler software forming a genome size of 23.3 Mb contained 30 scaffolds. Protein prediction identified 5105 candidates as protein-coding genes and these gene models were supported by expressed sequence tag and transcriptomic data. The annotated data was assembled into metabolic pathways in order to identify functional pathways and validate the accuracy of the annotation process. T. lanuginosus is usually found in composting plant material thus protein related to plant hydrolysis were analysed. The total number of plant biomass-degrading and related proteins that fall into the carbohydrate-active enzyme (CAZy) family was 224. Most of these proteins were similar to proteins found in other filamentous fungi. Surprisingly, T. lanuginosus contained a single gene coding for xylanase which hydrolyses xylan although this organism is well known for being among the highest producers of this enzyme. An important subset of the above group of proteins is the cellulose degrading-proteins as this can be used in biofuel production. Eight candidates belonging to this group were identified, making this fungus significant in the biofuels. Among the eight cellulase candidates, phylogenetic analysis revealed that three of them were closely related to Trichoderma reesei, a well known industrial cellulase-producer. Utilization of cellulase-related compounds was validated by phenotypic microarray experiments, with cellobiose having inducing biomass in T. lanuginosus. Proteins that are involved in high temperature survival are vital for the survival. of this thermophilic fungus. Interestingly, T. lanuginosus contains 19 heat shocking proteins which are responsible for thermostability. Another adaptation identified in this fungus is the accumulation of trehalose to combat heat stress. Furthermore, T. lanuginosus contains the highest reported number methyltransferases, which have been linked to producing thermostable proteins and higher energy production. Also because of this organism’s ability to grow on composting environments, the assimilation and ability to produce biomass on different carbon sources were analysed using phenotypic microarray technique. The results showed that xylose was the best compound to induce biomass followed by trehalose, maltose and maltotriose. The genomic sequencing of this fungus has provided valuable information that can be used for various biotechnological applications, as well as providing greater insights into its thermostability. Understanding the metabolic pathways involved may allow for manipulation to increase production of these enzymes or cloning into other hosts. This can have an impact in the field of biofuel production and other plant biomass-related processes.
8

The chitinolytic enzyme system of the compost-dwelling thermophilic fungus Thermomyces lanuginosus

Zhang, Meng January 2014 (has links)
Submitted in complete fulfillment for the Degree of Master of Technology (Biotechnology), Durban University of Technology, Durban, South Africa, 2014. / Chitin, a highly insoluble 1,4- -linked polymer of N-acetyl- -D-glucosamine, is the second-most abundant bio-polysaccharide in nature after cellulose. Most chitinolytic fungi are known to produce more than one kind of chitinase. The recent sequencing of the Thermomyces lanuginosus SSBP genome by our group has revealed four putative family 18 chitinases. In this study, three novel chitinase genes (chitl, chit2 and chit3) and the previously reported chit4 gene were cloned from Thermomyces lanuginosus SSBP and their gene structures were analysed. chit3, encoding a 36.6 kDa protein, and chit4, encoding a 44.1 kDa protein, were successfully expressed in Pichia pastoris. The recombinant Chit3 and Chit4 enzymes exhibited optimum activity at pH 4.0 and 5.0 and at 40oC and 50°C, respectively. Chit3 was stable at 40oC and retained 71% of its activity at 50°C after 60 min, while Chit4 was stable at 50°C and retained 56% of its activity at 60°C after 30 min. Both enzymes produced chitobiose as the major product using colloidal chitin, chitooligosaccharides and shrimp shell powder as substrates. Of the fungal strains tested, Chit3 displayed antifungal activity against Penicillium sp. and Aspergillus sp. This is the first report on the multi-chitinolytic system of T. lanuginosus and enzyme characterization has shown the potential of the enzymes to be used in degradation of the under-utilized bio-resource chitin. / PDF Full-text unavailable. Please refer to hard copy for Full-text / M
9

Análise e caracterização do secretoma do fungo termofílico Malbranchea pulchella linhagem 6278 / Secretome analysis and characterization of thermophilic fungus Malbranchea pulchella strain 6278

Nogueira, Carlaile Fernanda de Oliveira 20 April 2017 (has links)
A despolimerização enzimática de componentes de biomassa é um processo chave para indústrias de bioenergia. A busca por novas enzimas aumentou os estudos dos secretomas de microrganismos degradadores de biomassa. Os fungos filamentosos são importantes agentes na reciclagem de carbono na natureza, apresentando potenciais enzimas para a conversão de biomassa. Malbranchea pulchella é um ascomiceto termofílico bioprospectado na Floresta Atlântica (região de Minas Gerais-Brasil), cuja análise e caracterização do secretoma, juntamente com a capacidade de biodegradação, foram foco deste estudo. O cultivo semi-sólido deste fungo em substratos lignificado (madeira de eucalipto moída) e \"não lignificado\" (polpa Kraft branqueada) por 60 dias resultou em perdas de peso de cerca de 5% e 52%, respectivamente. Para o estudo da diversidade das enzimas produzidas por M. pulchella, o secretoma foi avaliado em culturas submersas de 3 dias, utilizando as fontes de carbono anteriormente mencionadas. Os resultados de LC-MS/MS mostraram que o fungo foi capaz de secretar uma série de enzimas lignocelulolíticas. As enzimas proeminentes foram as glicosil-hidrolases com um total de 29 e 37 CAZymes nos substratos lignificado e \"não-lignificado\", respectivamente, sendo as famílias GH3 e GH18 encontradas em maior número. Considerando as enzimas oxidativas, um total de 12 e 13 CAZymes nos substratos lignificado e \"não lignificado\", respectivamente, sendo as famílias AA7 e AA9 as mais predominantes. Também foram detectadas proteínas não-CAZymes apresentando domínios alergênicos, que estão relacionados com proteínas semelhantes a expansinas de plantas. O secretoma produzido com substrato de polpa branqueada foi utilizado em ensaio de hidrólise com polpa Kraft e também em contribuição com Celluclast 1,5 L para hidrólise de polpa de dissolução e de Avicel. Os resultados indicaram que M. pulchella produz uma maquinaria enzimática interessante, que pode degradar celulose amorfa e cristalina, sendo potencial aplicação em hidrólise da biomassa lignocelulósica. / Enzymatic depolymerization of biomass components is a key process for bioenergy industries. The search for new enzymes for this task has increased secretome studies in biomass-degrading microorganisms. Filamentous fungi are important players in carbon recycling in nature, presenting potential enzymes for biomass conversion. Malbranchea pulchella is a thermophilic ascomycete bio prospected in Brazilian Atlantic forest whose secretome analysis and characterization together with biodegradation ability were focus of this study. Semi-solid cultivation of this fungus on lignified (milled eucalyptus wood) and non-lignified (bleached eucalyptus pulp) substrates for 60 days resulted in almost 5% and 52% weight losses, respectively. To understand the diversity of enzymes produced by M. pulchella the secretome was evaluated in 3-day submerse cultures using the previously mentioned carbon sources. LC-MS/MS results showed the fungus was able to secrete an array of lignocellulolytic enzymes. The prominent enzymes were glycosyl hydrolases with a total of 29 and 37 CAZymes in lignified and non-lignified substrates, respectively, with GH3 and GH18 families found in greatest number. Considering the oxidative enzymes, a total of 12 and 13 CAZymes were found in lignified and non-lignified substrates, respectively, being AA7 and AA9 families most expressive. Non-CAZymes proteins showing allergen domains, which are related with expansin-like proteins from plants, were also detected. The secretome produced with bleached eucalyptus pulp substrate was assayed for hydrolysis of Kraft pulp and in contribution with Celluclast 1.5 L for dissolving pulp and Avicel hydrolysis as well. Results indicated that M. pulchella produce an interesting enzymatic array that can disrupt both amorphous and crystalline cellulose, demonstred as potencial secretome for biomass hydrolysis.
10

Análise e caracterização do secretoma do fungo termofílico Malbranchea pulchella linhagem 6278 / Secretome analysis and characterization of thermophilic fungus Malbranchea pulchella strain 6278

Carlaile Fernanda de Oliveira Nogueira 20 April 2017 (has links)
A despolimerização enzimática de componentes de biomassa é um processo chave para indústrias de bioenergia. A busca por novas enzimas aumentou os estudos dos secretomas de microrganismos degradadores de biomassa. Os fungos filamentosos são importantes agentes na reciclagem de carbono na natureza, apresentando potenciais enzimas para a conversão de biomassa. Malbranchea pulchella é um ascomiceto termofílico bioprospectado na Floresta Atlântica (região de Minas Gerais-Brasil), cuja análise e caracterização do secretoma, juntamente com a capacidade de biodegradação, foram foco deste estudo. O cultivo semi-sólido deste fungo em substratos lignificado (madeira de eucalipto moída) e \"não lignificado\" (polpa Kraft branqueada) por 60 dias resultou em perdas de peso de cerca de 5% e 52%, respectivamente. Para o estudo da diversidade das enzimas produzidas por M. pulchella, o secretoma foi avaliado em culturas submersas de 3 dias, utilizando as fontes de carbono anteriormente mencionadas. Os resultados de LC-MS/MS mostraram que o fungo foi capaz de secretar uma série de enzimas lignocelulolíticas. As enzimas proeminentes foram as glicosil-hidrolases com um total de 29 e 37 CAZymes nos substratos lignificado e \"não-lignificado\", respectivamente, sendo as famílias GH3 e GH18 encontradas em maior número. Considerando as enzimas oxidativas, um total de 12 e 13 CAZymes nos substratos lignificado e \"não lignificado\", respectivamente, sendo as famílias AA7 e AA9 as mais predominantes. Também foram detectadas proteínas não-CAZymes apresentando domínios alergênicos, que estão relacionados com proteínas semelhantes a expansinas de plantas. O secretoma produzido com substrato de polpa branqueada foi utilizado em ensaio de hidrólise com polpa Kraft e também em contribuição com Celluclast 1,5 L para hidrólise de polpa de dissolução e de Avicel. Os resultados indicaram que M. pulchella produz uma maquinaria enzimática interessante, que pode degradar celulose amorfa e cristalina, sendo potencial aplicação em hidrólise da biomassa lignocelulósica. / Enzymatic depolymerization of biomass components is a key process for bioenergy industries. The search for new enzymes for this task has increased secretome studies in biomass-degrading microorganisms. Filamentous fungi are important players in carbon recycling in nature, presenting potential enzymes for biomass conversion. Malbranchea pulchella is a thermophilic ascomycete bio prospected in Brazilian Atlantic forest whose secretome analysis and characterization together with biodegradation ability were focus of this study. Semi-solid cultivation of this fungus on lignified (milled eucalyptus wood) and non-lignified (bleached eucalyptus pulp) substrates for 60 days resulted in almost 5% and 52% weight losses, respectively. To understand the diversity of enzymes produced by M. pulchella the secretome was evaluated in 3-day submerse cultures using the previously mentioned carbon sources. LC-MS/MS results showed the fungus was able to secrete an array of lignocellulolytic enzymes. The prominent enzymes were glycosyl hydrolases with a total of 29 and 37 CAZymes in lignified and non-lignified substrates, respectively, with GH3 and GH18 families found in greatest number. Considering the oxidative enzymes, a total of 12 and 13 CAZymes were found in lignified and non-lignified substrates, respectively, being AA7 and AA9 families most expressive. Non-CAZymes proteins showing allergen domains, which are related with expansin-like proteins from plants, were also detected. The secretome produced with bleached eucalyptus pulp substrate was assayed for hydrolysis of Kraft pulp and in contribution with Celluclast 1.5 L for dissolving pulp and Avicel hydrolysis as well. Results indicated that M. pulchella produce an interesting enzymatic array that can disrupt both amorphous and crystalline cellulose, demonstred as potencial secretome for biomass hydrolysis.

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