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1.
Rio de Janeiro; s.n; 2019. xiv, 152 p. ilus.
Tese em Português | LILACS | ID: biblio-1049943

RESUMO

Celulases fúngicas têm sido usadas para degradar a biomassa lignocelulósica para a produção de bioetanol. Celulases industriais como Cel7A de Trichoderma reesei (TrCel7A) são críticas neste processo. A compreensão da estrutura e dinâmica é crucial para a reengenharia da atividade celulolítica. Esta enzima é formada por dois domínios ligados por um linker flexível e altamente glicosilado. No entanto, a flexibilidade do linker tem dificultado a determinação da estrutura completa da Cel7A. Assim, na ausência de dados experimentais de alta resolução, aplicamos a modelagem integrativa para construir um modelo da enzima completa. Em seguida, estudamos os efeitos da glicosilação na estrutura e dinâmica da apo TrCel7A por meio de simulações. A análise da dinâmica essencial mostrou que a O-glicosilação no linker levou à estabilização da dinâmica global da proteína. Os glicanos O-ligados parecem restringir a distribuição dos ângulos diedros desta região, selecionando conformações mais alongadas. Além da flexibilidade reduzida, os movimentos interdomínios funcionais foram preservados no sistema glicosilado. Em contraste, observamos grande plasticidade conformacional na ausência de glicosilação, mas os domínios funcionais frequentemente colapsaram. Nós relatamos aqui evidências de que a flexibilidade dirigida no linker de Cel7A por mutações pontuais, incluindo modificações de sítios de glicosilação, poderia ser uma estratégia promissora para melhorar a atividade da celulase. (AU)


Assuntos
Humanos , Trichoderma , Glicosilação , Mutagênese Insercional , Celulases
2.
Braz. j. microbiol ; 49(4): 879-884, Oct.-Dec. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1039268

RESUMO

ABSTRACT The multi-enzyme complex (crude extract) of white rot fungi Pleurotus ostreatus, Pleurotus eryngii, Trametes versicolor, Pycnosporus sanguineus and Phanerochaete chrysosporium were characterized, evaluated in the hydrolysis of pretreated pulps of sorghum straw and compared efficiency with commercial enzyme. Most fungi complexes had better hydrolysis rates compared with purified commercial enzyme.


Assuntos
Proteínas Fúngicas/química , Sorghum/química , Celulases/química , Fungos/enzimologia , Lignina/química , Proteínas Fúngicas/metabolismo , Caules de Planta/microbiologia , Caules de Planta/química , Sorghum/microbiologia , Celulases/metabolismo , Biocatálise , Fungos/química , Hidrólise , Lignina/metabolismo
3.
Electron. j. biotechnol ; 19(6): 56-62, Nov. 2016. ilus
Artigo em Inglês | LILACS | ID: biblio-840314

RESUMO

Background: Endoglucanase, one of three type cellulases, can randomly cleave internal p-1,4-linkages in cellulose polymers. Thus, it could be applied in agricultural and industrial processes. Results: A novel endoglucanase gene (JqCel5A) was cloned from Jonesia quinghaiensis and functionally expressed in Escherichia coli Rosetta (DE3). It contained 1722 bp and encoded a 573-residue polypeptide consisting of a catalytic domain of glycoside hydrolase family 5 (GH5) and a type 2 carbohydrate-binding module (CBM2), together with a predicted molecular mass of 61.79 kD. The purified JqCel5A displayed maximum activity at 55°C and pH 7.0, with 21.7 U/mg, 26.19 U/mg and 4.81 U/mg towards the substrate carboxymethyl cellulose, barley glucan and filter paper, respectively. Interestingly, JqCel5A exhibited high pH stability over a broad pH range of pH (3-11), and had good tolerance to a wide variety of deleterious chemicals including heavy metals and detergent. The catalytic mechanism of JqCel5A was also investigated by site mutagenesis and homology-modeling in this study. Conclusions: It was believed that these properties might make JqCel5A to be potentially used in the suitable industrial catalytic condition, which has a broad pH fluctuation and/or chemical disturbance.


Assuntos
Actinomycetales/enzimologia , Celulases/química , Celulases/isolamento & purificação , Celulases/genética , Concentração de Íons de Hidrogênio , Testes de Mutagenicidade , Temperatura
4.
Electron. j. biotechnol ; 19(6): 79-83, Nov. 2016. ilus
Artigo em Inglês | LILACS | ID: biblio-840317

RESUMO

Background: Cold-active endo-1, 4-β-glucanase (EglC) can decrease energy costs and prevent product denaturation in biotechnological processes. However, the nature EglC from C. farmeri A1 showed very low activity (800 U/L). In an attempt to increase its expression level, C. farmeri EglC was expressed in Escherichia coli as an N-terminal fusion to protein S (ProS) from Myxococcus xanthus. Results: A novel expression vector, pET(ProS-EglC), was successfully constructed for the expression of C. farmeri EglC in E. coli. SDS-PAGE showed that the recombinant protein (ProS-EglC) was approximately 60 kDa. The activity of ProS-EglC was 12,400 U/L, which was considerably higher than that of the nature EglC (800 U/L). ProS-EglC was active at pH 6.5-pH 8.0, with optimum activity at pH 7.0. The recombinant protein was stable at pH 3.5-pH 6.5 for 30 min. The optimal temperature for activity of ProS-EglC was 30°C-40°C. It showed greater than 50% of maximum activity even at 5°C, indicating that the ProS-EglC is a cold-active enzyme. Its activity was increased by Co2+ and Fe2+, but decreased by Cd2+, Zn2+, Li+, methanol, Triton-X-100, acetonitrile, Tween 80, and SDS. Conclusions: The ProS-EglC is promising in application of various biotechnological processes because of its cold-active characterizations. This study also suggests a useful strategy for the expression of foreign proteins in E. coli using a ProS tag.


Assuntos
Celulases/metabolismo , Citrobacter/enzimologia , Escherichia coli/enzimologia , Myxococcus xanthus/enzimologia , Temperatura Baixa , Vetores Genéticos , Proteínas Recombinantes
5.
Braz. j. microbiol ; 47(1): 110-119, Jan.-Mar. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-775128

RESUMO

Abstract The bioconversion of cellulosic wastes into high-value bio-products by saccharification and fermentation processes is an important step that can reduce the environmental pollution caused by agricultural wastes. In this study, enzymatic saccharification of treated and untreated date palm cellulosic wastes by the cellulases from Geobacillus stearothermophilus was optimized. The alkaline pre-treatment of the date palm wastes was found to be effective in increasing the saccharification percentage. The maximum rate of saccharification was found at a substrate concentration of 4% and enzyme concentration of 30 FPU/g of substrate. The optimum pH and temperature for the bioconversions were 5.0 and 50 °C, respectively, after 24 h of incubation, with a yield of 31.56 mg/mL of glucose at a saccharification degree of 71.03%. The saccharification was increased to 94.88% by removal of the hydrolysate after 24 h by using a two-step hydrolysis. Significant lactic acid production (27.8 mg/mL) was obtained by separate saccharification and fermentation after 72 h of incubation. The results indicate that production of fermentable sugar and lactic acid is feasible and may reduce environmental pollution by using date palm wastes as a cheap substrate.


Assuntos
Celulases/metabolismo , Celulose/metabolismo , Geobacillus stearothermophilus/enzimologia , Glucose/metabolismo , Resíduos Industriais , Ácido Láctico/metabolismo , Phoeniceae/metabolismo , Álcalis , Biotransformação , Fermentação , Concentração de Íons de Hidrogênio , Phoeniceae/efeitos dos fármacos , Temperatura
6.
Braz. j. microbiol ; 46(4): 1269-1277, Oct.-Dec. 2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-769645

RESUMO

Abstract A thermohalophilic fungus, Aspergillus terreus AUMC 10138, isolated from the Wadi El-Natrun soda lakes in northern Egypt was exposed successively to gamma and UV-radiation (physical mutagens) and ethyl methan-sulfonate (EMS; chemical mutagen) to enhance alkaline cellulase production under solid state fermentation (SSF) conditions. The effects of different carbon sources, initial moisture, incubation temperature, initial pH, incubation period, inoculum levels and different concentrations of NaCl on production of alkaline filter paper activity (FPase), carboxymethyl cellulase (CMCase) and β-glucosidase by the wild-type and mutant strains of A. terreus were evaluated under SSF. The optimum conditions for maximum production of FPase, CMCase and β-glucosidase were found to be the corn stover: moisture ratio of 1:3(w/v), temperature 45 °C, pH range, 9.0–11.0, and fermentation for 4, 4 and 7 day, respectively. Inoculum levels of 30% for β-glucosidase and 40% for FPase, CMCase gave the higher cellulase production by the wild-type and mutant strains, respectively. Higher production of all three enzymes was obtained at a 5% NaCl. Under the optimized conditions, the mutant strain A. terreus M-17 produced FPase (729 U/g), CMCase (1,783 U/g), and β-glucosidase (342 U/g), which is, 1.85, 1.97 and 2.31-fold higher than the wild-type strain. Our results confirmed that mutant strain M-17 could be a promising alkaline cellulase enzyme producer employing lignocellulosics especially corn stover.


Assuntos
Aspergillus/enzimologia , Aspergillus/metabolismo , Celulases/metabolismo , Mutagênese , Zea mays/metabolismo , Aspergillus/efeitos dos fármacos , Aspergillus/efeitos da radiação , Meios de Cultura/química , Egito , Metanossulfonato de Etila , Concentração de Íons de Hidrogênio , Lagos/microbiologia , Técnicas Microbiológicas , Cloreto de Sódio/metabolismo , Temperatura , Raios Ultravioleta
7.
Acta sci., Biol. sci ; 37(1): 15-22, jan.- mar. 2015. ilus
Artigo em Inglês | LILACS | ID: biblio-847977

RESUMO

Studies on new microbial sources of cellulase and accurate assessment of the steps that increase cellulase production are essential strategies to reduce costs of various processes using such enzymes. This study aimed at the selection of cellulase-producing filamentous fungi, and at the research of parameters involving cellulase production by submerged fermentation. The first test consisted of selecting the best cellulase-producing microorganisms (FPase) in Erlenmeyer flasks containing 200 mL of specific growth medium. The next test was designed to further investigate the enzyme production in fermentation with four types of soluble sugars: glucose, lactose, sucrose and xylose. In bioreactor tests, three different inoculation strategies were analyzed. The best FPase activity was presented by the strain Trichoderma sp. CMIAT 041 (49.9 FPU L-1) and CMCase by the fungus Lasiodiplodia theobromae CMIAT 096 (350.0 U L-1). Sucrose proved to be the best option among the soluble sugars tested, with higher rates of FPase activity (49.9 FPU L-1) and CMCase (119.7 U L-1). The best inoculation strategy for the bioreactor was a spore suspension obtained from a semi-solid state fermentation of wheat bran for 72h.


Estudos sobre novas fontes microbianas e análises mais acuradas das etapas que compõem a produção de celulases são essenciais como estratégias para diminuir os custos gerados pelo uso de celulases nos processos de obtenção de açúcares fermentescíveis. O trabalho teve como objetivo a seleção de fungos filamentosos produtores de celulases e a investigação de parâmetros que envolvem a produção enzimática em fermentação submersa. O primeiro teste consistiu em selecionar os melhores fungos produtores de celulases totais em frascos Erlenmeyer contendo 200 mL de meio de cultura específico. O teste subsequente teve o intuito de investigar a produção enzimática com quatro tipos de açúcares solúveis: glicose, lactose, sacarose e xilose. Nos testes em biorreator foram analisados três diferentes estratégias de inoculação. Na etapa de seleção a melhor atividade de FPase foi apresentada por Trichoderma sp. CMIAT 041 (49,9 FPU L-1) e CMCase pelo fungo Lasiodiplodia theobromae CMIAT 096 (350,0 U L-1). O uso de sacarose mostrou-se ser a melhor opção dentre os açúcares solúveis testados, apresentando os maiores valores de atividade de FPase (49,9 FPU L-1) e CMCase (119,7 U L-1). A melhor estratégia de inoculação foi a suspensão de esporos obtidos a partir de fermentação em farelo de trigo, no tempo 72h.


Assuntos
Brasil , Celulases , Ecossistema , Fermentação , Fungos
8.
Acta sci., Biol. sci ; 36(2): 215-222, abr.- jun. 2014. ilus, tab
Artigo em Inglês | LILACS | ID: biblio-849049

RESUMO

Nowadays, the isolation of new bacterial strains that produce enzymes with novel properties is a subject of great relevance to the scientific community. This study, in order to search for producers of new cellulase strains, investigated the avicelase production by thermophilic Bacillus sp. strain SMIA-2. The best avicelase activity was observed in a culture medium containing 0.5% (w v-1) avicel and 0.5% (w v-1) corn steep liquor with initial pH 7.5- 8.0 incubated at 50 oC. When avicel was replaced in the medium by the treated sugarcane bagasse (0.5%, w v-1) the avicelase activity levels were not affected. Studies on the avicelase characterization revealed that the optimum pH of the enzyme was found to be 8.5 and the enzyme retained more than 80% of its activity after incubation at room temperature for 2h at pH 6.5-8.5. The optimum temperature of this enzyme was 70oC and the enzyme retained 67% of the original activity after 20 min. of heat treatment at 70oC. Avicelase was stimulated by Mn2+ and Co2+, whereas Hg2+ greatly inhibited the enzyme activity.


Atualmente, o isolamento de estirpes de bactérias que produzem enzimas com novas propriedades é um tema de grande relevância para a comunidade científica. Este trabalho, buscando por novas cepas produtoras de celulases, investigou a produção de avicelases pelo termofílico Bacillus sp. cepa SMIA-2. A melhor atividade da enzima foi obtida em uma cultura contendo 0,5% (p v-1) avicel e 0,5% (p v-1) água de maceração de milho com pH inicial de pH 7,5-8,0 e incubada a 50oC. A substituição da avicel no meio de cultura pelo bagaço de cana- de- açúcar tratado (0,5%, p v-1) não afetou os níveis de atividade da avicelase. Estudos sobre a caracterização da avicelase revelaram que o pH para atividade ótima da enzima foi 8,5 e que a mesma reteve mais de 80% de sua atividade após ser incubada à temperatura ambiente por 2 h a pH 6,5-8,5. A temperatura ótima da avicelase foi 70oC e a enzima reteve 67% da sua atividade original após 20 min. de incubação a 70oC. A avicelase foi estimulada pelos íons Mn2+ e Co2+, ao passo que Hg2+ inibiu a atividade da enzima.


Assuntos
Bacillus , Celulases , Saccharum , Zea mays
9.
Braz. j. microbiol ; 43(4): 1467-1475, Oct.-Dec. 2012. graf, tab
Artigo em Inglês | LILACS | ID: lil-665834

RESUMO

The characteristics of an endoglucanase produced by a Trichoderma virens strain T9 newly isolated from a palm-fruit husk dump site, its physiological characteristics and enzyme production were studied. Whole cells of the depolymerizing-enzyme producing T. virens were applied to palm-fruit husk and bird performance characteristics when employed as poultry diet additive were considered. Endoglucanase activity in submerged fermentation was 1.6 nkat. Optimum activity was recorded at pH 6.0 and 55ºC. The enzyme retained 50% residual glucanase activity at 70ºC for 10 minutes. 1.0% Tween-80 and SDS yielded endoglucanase activity 2.15 times higher than the control. Activity wasboosted by 20mM Ca2+ (115.0%); 10mM K+ (106.5%); and was totally inhibited by 1mM Hg2+. The addition of T. virens -fermented palm-fruit husk with other layer feed components on the bird characteristics showed that change in bird weight between the control and test birds were not significantly different (p>0.05) but differed in terms of daily feed ingested (p<0.05). The feed to weight-gain ratio was best with the unmodified palm-fruit husk based diet (8.59). There was no significant difference in the egg weights from modified palm-fruit husk based diet and control (p>0.05). The shell thickness (0.64mm) and yolk content (23.61%) were highest in the microbially-modified husk diet. The alternative to maize based diets proffered by the application of T. virens -modified palm-fruit husk in poultry nutrition in terms of bird weight and feed to weight-gain ratio affords the poultry farmer an economic advantage and allows for a greater utilization of the maize in human diets.


Assuntos
Celulases/análise , /análise , Trichoderma/fisiologia , Trichoderma/isolamento & purificação , Microbiologia Industrial , Metodologia
10.
Braz. j. microbiol ; 43(4): 1508-1515, Oct.-Dec. 2012. graf
Artigo em Inglês | LILACS | ID: lil-665838

RESUMO

The mushroom Pleurotus ostreatus has nutritional and medicinal characteristics that depend on the growth substrate. In nature, this fungus grows on dead wood, but it can be artificially cultivated on agricultural wastes (coffee husks, eucalyptus sawdust, corncobs and sugar cane bagasse). The degradation of agricultural wastes involves some enzyme complexes made up of oxidative (laccase, manganese peroxidase and lignin peroxidase) and hydrolytic enzymes (cellulases, xylanases and tanases). Understanding how these enzymes work will help to improve the productivity of mushroom cultures and decrease the potential pollution that can be caused by inadequate discharge of the agroindustrial residues. The objective of this work was to assess the activity of the lignocellulolytic enzymes produced by two P. ostreatus strains (PLO 2 and PLO 6). These strains were used to inoculate samples of coffee husks, eucalyptus sawdust or eucalyptus bark add with or without 20 % rice bran. Every five days after substrate inoculation, the enzyme activity and soluble protein concentration were evaluated. The maximum activity of oxidative enzymes was observed at day 10 after inoculation, and the activity of the hydrolytic enzymes increased during the entire period of the experiment. The results show that substrate composition and colonization time influenced the activity of the lignocellulolytic enzymes.


Assuntos
Celulases/análise , Ativação Enzimática , Fungos/crescimento & desenvolvimento , Pleurotus/crescimento & desenvolvimento , Pleurotus/isolamento & purificação , Xilanos/análise , Agaricales , Biodegradação Ambiental , Amostras de Alimentos , Metodologia , Resíduos
11.
Braz. j. microbiol ; 43(4): 1536-1544, Oct.-Dec. 2012. graf, tab
Artigo em Inglês | LILACS | ID: lil-665841

RESUMO

This work is aimed to produce endoglucanase through solid state fermentation in a packed bed bioreactor with the use of the fungus Myceliophtora sp. I-1D3busing a mixture of wheat bran (WB) and sugar cane bagasse (SCB) as culture medium. Preliminary tests were performed in polypropylene plastic bags, controlling the variables temperature (40, 45, and 50ºC), initial moisture content (75, 80, and 85%, w.b.), and weight proportion SCB/WB (1:1, 7:3, and 9:1). The highest enzyme activities in plastic bags were obtained using the substrate proportion of 7:3, 50ºC temperature, and 80% initial moisture content (878 U/grams of dry solid). High activities of filter-paper cellulase and xylanase were also obtained in plastic bags and some results are reported. For the packed bed experiments, the temperature (45 and 50ºC) and the air flow rate (80, 100 and 120L/h) were the controlled variables. Activity of endoglucanase was similar to plastic bag tests. A longitudinal gradient of moisture content, was observed increasing from the bottom to the top of the reactor, even though the longitudinal enzyme activity profile was flat for almost the whole bed. Air flow rate did not affect enzyme activity, while experiments carried out at 50ºC showed higher enzyme activities. The maximum temperature peak observed was at about 6ºC above the process temperature.


Assuntos
Celulases/análise , Fermentação , Fungos/enzimologia , Fungos/isolamento & purificação , Polipropilenos/análise , Polipropilenos/isolamento & purificação , Saccharum , Triticum , Xilanos/análise , Amostras de Alimentos , Microbiologia Industrial , Métodos , Indústria de Plásticos
12.
Braz. j. microbiol ; 43(3): 1062-1071, July-Sept. 2012. ilus, graf, tab
Artigo em Inglês | LILACS | ID: lil-656675

RESUMO

Twenty-seven thermophilic and thermotolerant fungal strains were isolated from soil, decaying organic matter and sugarcane piles based on their ability to grow at 45ºC on medium containing corn straw and cardboard as carbon sources. These fungi were identified in the genera Aspergillus, Thermomyces, Myceliophthora, Thermomucor and Candida. The majority of the isolated strains produced xylanase and cellulases under solid state fermentation (SSF). The highest cellulase and xylanase productions were obtained by the cultivation of the strains identified as Aspergillus fumigatus M.7.1 and Myceliophthora thermophila M.7.7. The enzymes from these strains exhibited maximum activity at pH 5.0 and at 60 and 70ºC. The endo-glucanase from A. fumigatus was stable from 40ºC to 65ºC and both endo-glucanase and xylanase from M. thermophila were stable in this temperature range when in absence of substrate. The enzymes were stable from pH 4.0 to 9.0.


Assuntos
Carbono/análise , Celulases/análise , Fermentação , Fungicidas Industriais/análise , Fungos Mitospóricos/enzimologia , Fungos Mitospóricos/isolamento & purificação , Condições do Solo , Xilanos/análise , Ativação Enzimática , Métodos
13.
Braz. j. microbiol ; 43(2): 467-475, Apr.-June 2012. graf, tab
Artigo em Inglês | LILACS | ID: lil-644460

RESUMO

Aspergillus niger F7 isolated from soil was found to be the potent producer of cellulase and xylanase. The residue of forest species Toona ciliata, Celtris australis, Cedrus deodara and Pinus roxburghii was selected as substrate for biodegradation study due to its easy availability and wide use in industry. It was subjected to alkali (sodium hydroxide) treatment for enhancing its degradation. Biodegradation of forest waste by hydrolytic enzymes (cellulase and xylanase) secreted by A. niger under solid state fermentation (SSF) was explored. SSF of pretreated forest biomass was found to be superior over untreated forest biomass. Highest extracellular enzyme activity of 2201±23.91 U/g by A. niger was shown in pretreated C. australis wood resulting in 6.72±0.20 percent hydrolysis and 6.99±0.23 biodegradation index (BI). The lowest BI of 1.40±0.08 was observed in untreated saw dust of C. deodara having the least enzyme activity of 238±1.36 U/g of dry matter. Biodegradation of forest biomass under SSF was increased many folds when moistening agent i.e. tap water had been replaced with modified basal salt media (BSM). In BSM mediated degradation of forest waste with A. niger, extracellular enzyme activity was increased up to 4089±67.11 U/g of dry matter in turn resulting in higher BI of 15.4±0.41 and percent hydrolysis of 19.38±0.81 in pretreated C. australis wood. A. niger exhibited higher enzyme activity on pretreated biomass when moistened with modified BSM in this study. Statistically a positive correlation has been drawn between these three factors i.e. enzyme activity, BI and percent hydrolysis of forest biomass thus proving their direct relationship with each other.


Assuntos
Zona Árida , Aspergillus niger/enzimologia , Aspergillus niger/isolamento & purificação , Biomassa , Celulases/análise , Celulases/isolamento & purificação , Xilanos/análise , Xilanos/isolamento & purificação , Biodegradação Ambiental , Ativação Enzimática , Hidrólise , Métodos , Solo
14.
Electron. j. biotechnol ; 15(3): 2-2, May 2012. ilus, tab
Artigo em Inglês | LILACS | ID: lil-640546

RESUMO

The gram-positive spore-forming bacteria, Bacillus thuringiensis (Bt) strains produced novel cellulases which could liberate glucose from soluble cellulose, carboxymethyl cellulose (CMC), and insoluble crystalline cellulose. The maximal cellulase activities were obtained after 60 hrs incubation at 28ºC in a LB broth medium with 1 percent CMC. Maximum CMCase activities were got at 40ºC and pH 4.0, respectively, and more than 50 percent of its maximal activity was retained at 40-60ºC for 1 hr, while approximately 40 percent of its maximal activity was also retained after incubating at 70ºC for 1 hr. Most metal ions and reagents such as Ca2+, Mg2+, Cd2+, Pb2+, Zn2+, Cu2+, EDTA, and SDS inhibited the enzyme activities, but K+ and Mn2+ activated the activities. The enzymes from Bacillus thuringiensis strains could be applied in bioconversion of lignocellulosic biomass into fermentable sugars.


Assuntos
Bacillus thuringiensis/enzimologia , Celulases/fisiologia , Estabilidade Enzimática , Fermentação , Concentração de Íons de Hidrogênio , Temperatura
15.
Braz. j. microbiol ; 42(3): 1119-1127, July-Sept. 2011. ilus, tab
Artigo em Inglês | LILACS | ID: lil-607543

RESUMO

Aspergillus niger was used for cellulase production in submerged (SmF) and solid state fermentation (SSF). The maximum production of cellulase was obtained after 72 h of incubation in SSF and 96 h in Smf. The CMCase and FPase activities recorded in SSF were 8.89 and 3.56 U per g of dry mycelial bran (DBM), respectively. Where as in Smf the CMase & FPase activities were found to be 3.29 and 2.3 U per ml culture broth, respectively. The productivity of extracellular cellulase in SSF was 14.6 fold higher than in SmF. The physical and nutritional parameters of fermentation like pH, temperature, substrate, carbon and nitrogen sources were optimized. The optimal conditions for maximum biosynthesis of cellulase by A. niger were shown to be at pH 6, temperature 30 ºC. The additives like lactose, peptone and coir waste as substrate increased the productivity both in SmF and SSF. The moisture ratio of 1:2 (w/v) was observed for optimum production of cellulase in SSF.


Assuntos
Aspergillus niger/enzimologia , Celulases/análise , Celulases/biossíntese , Fermentação , Lactose/análise , Peptonas/análise , Ativação Enzimática , Métodos , Técnicas
16.
Electron. j. biotechnol ; 13(5): 5-6, Sept. 2010. ilus, tab
Artigo em Inglês | LILACS | ID: lil-591887

RESUMO

Cellulase is a group of enzymes (endoglucanase, exoglucanase and beta-glucosidase) required for cellulosic feedstock hydrolysis during bioethanol production. The use of recombinant cellulase is a strategy to reduce the enzyme cost. In this context, the present work describes the construction of a cellulase expression vector (pEglABglA), which allowed constitutive co-expression of endoglucanase A (EglA) from an endophytic Bacillus pumilus and the hyperthermophilic beta-glucosidase A (BglA) from Fervidobacterium sp. in Escherichia coli. When compared to the non-modified strain DH5 alpha, the recombinant Escherichia coli DH5 alpha (pEglABglA) reduced fivefold the viscosity of the carboxymethylcellulose medium (CMC-M). Also, it presented almost 30-fold increase in reducing sugar released from CMC-M, enabling the recombinant strain to grow using CMC as the sole carbon and energy source. When cultivated in rich media, specific growth rates of recombinant E. coli strains BL21, JM101 and Top10 were higher than those of DH5 alpha and DH10B strains. The constructed plasmid (pEglABglA) can be used as backbone for further cellulase gene addition, which may enhance even more E. coli cellulolytic capacity and growth rate.


Assuntos
Celulases/metabolismo , Escherichia coli/enzimologia , Etanol , Escherichia coli/crescimento & desenvolvimento , Hidrólise , beta-Glucosidase/metabolismo
17.
Electron. j. biotechnol ; 12(3): 8-9, July 2009. ilus, tab
Artigo em Inglês | LILACS | ID: lil-551886

RESUMO

The cellulase enzyme production is a key issue in the enzymatic hydrolysis of lignocellulosic materials. Since fungal morphology influences the productivity of fungal fermentations, it is of major importance to well know the fungal behavior during culture for cellulase production. In this work, the influence of medium supplementation, with different buffer systems at two different concentrations and pH conditions, on the morphology of T. reesei Rut C-30 and cellulase production, was investigated. A medium without buffer was used as control. The results suggest that fungal morphology is significantly dependent on the addition of different buffer systems to the nutrient broth. The mycelial morphology shows a clear transition from clumped to pelleted forms in cultures with variation of buffer systems and concentration. The higher filter paper activity was obtained using 100 mM succinate buffer, at pH 4.8, in the medium supplementation, corresponding to a dispersed mycelial morphology.


Assuntos
Celulases/biossíntese , Celulases/provisão & distribução , Celulases/síntese química , Trichoderma/enzimologia , Trichoderma/metabolismo , Fermentação , Hidrólise , Fungos/citologia , Fungos/ultraestrutura
18.
Braz. j. microbiol ; 39(1): 122-127, Jan.-Mar. 2008. graf, tab
Artigo em Inglês | LILACS | ID: lil-480687

RESUMO

Cellulase is a complex enzyme system, commercially produced by filamentous fungi under solid-state and submerged cultivation. It has wide applicability in textile, food and beverage industry for effective saccharification process. In this study, cellulolytic enzyme activity, particularly endoglucanase of 26 Streptomyces strains isolated from garden soil was examined, including two isolates selected on the basis of potential cellulolytic activity on Bennett's agar medium. To enhance the endoglucanase formation in broth culture, different conditions including carbon and nitrogen sources, and growth conditions were tested. The maximum endoglucanase activity (11.25-11.90 U/mL) was achieved within 72-88 h in fermentation medium containing Tween-80, followed by phosphate sources. Both cellulolytic Streptomyces isolates gave almost equal quantity of enzyme in all trials. However the effect of medium ingredients on endoglucanase induction diverged with strains in some extent.


A celulase é um sistema enzimático complexo, produzido comercialmente a partir de fungos filamentosos através de cultivo em estádio sólido e submerso. Tem uma grande aplicação na indústria têxtil e de alimentos e bebidas no processo de sacarificação. Nesse estudo, examinou-se a atividade celulolítica, especialmente de englucanase, de 26 cepas de Streptomyces isoladas de solo, incluindo duas cepas selecionadas por sua atividade celulolítica no ágar Bennett. Para estimular a produção de englucanase em meio de cultura, diferentes condições de cultivo, incluindo fonte de carbono e nitrogênio e condições de crescimento, foram avaliadas. A atividade máxima de glucanase (11,25 a 11,90 U/mL) foi obtida em 72-88h em meio de cultura contendo Tween-80, seguido por fontes de fosfato. Ambas as cepas celulolíticas de Streptomyces produziram quase a mesma quantidade de enzima em todos os experimentos. Entretanto, o efeito dos ingredientes do meio na indução da glucanase divergiu de acordo com a cepa.


Assuntos
Ensaios Enzimáticos Clínicos , Celulases/análise , Fungos/enzimologia , Fungos/isolamento & purificação , Técnicas In Vitro , Meios de Cultura/isolamento & purificação , Streptomyces/enzimologia , Streptomyces/isolamento & purificação , Fermentação , Métodos , Solo , Indústria Têxtil
19.
Electron. j. biotechnol ; 7(3): 07-08, Dec. 2004. ilus, graf, tab
Artigo em Inglês | LILACS | ID: lil-448764

RESUMO

The influence of carbon and nitrogen sources on the production of exo-glucanase was investigated. The enzyme production was variable according to the carbon or nitrogen source used. Levels of beta-cellobiohydrolase (CBH) were minimal in the presence of even low concentrations of glucose. Enzyme production was stimulated by other carbohydrates and thus is subject to carbon source control by easily metabolizable sugars. In Dubos medium, on cellobiose, the cellobiohydrolase titres were 2-to 110-fold higher with cells growing on monomeric sugars and 2.7 times higher than cells growing on other disaccharides. alpha-Cellulose was the most effective inducer of beta-cellobiohydrlase and filter paperase (FPase) activities, followed by kallar grass straw. Exogenously supplied glucose inhibited the synthesis of the enzyme in cultures of Cellulomonas flavigena. Nitrates were the best nitrogen sources and supported greater cell mass, cellobiohydrolase and FPase production. During growth on alpha-cellulose containing 8-fold sodium nitrate concentration, maximum volumetric productivities (Qp) of beta-cellobiohydrolase and FPase were 87.5 and 79.5 IU/l./h respectively and are significantly higher than the values reported for some other potent fungi and bacteria.


Assuntos
Carbono/metabolismo , Cellulomonas/enzimologia , /biossíntese , Nitrogênio/metabolismo , Cellulomonas/metabolismo , Celulases/biossíntese , Entropia , Indução Enzimática , Fermentação , Concentração de Íons de Hidrogênio , Cinética , Temperatura
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