Actividad de las enzimas hidrolíticas en cepas del hongo shiitake (Lentinula edodes) cultivadas en pulpa de café / Hydrolytic enzyme activities in shiitake mushroom (Lentinula edodes) strains cultivated on coffee pulp

Se estudió la producción de enzimas hidrolíticas (celulasas, laminarinasas y xilanasas) en cultivos de Lentinula edodes en pulpa de café estéril. Se tomaron muestras de sustrato colonizado por el micelio después de 7, 14, 21, 28 y 35 días de incubación a 25°C (W1 a W5) y durante el período de fructificación en diferentes etapas: formación de primordios (PF), primera cosecha (H) y una semana después de la primera cosecha (PH). La actividad enzimática fue menor al inicio del crecimiento micelial y mostró mayores niveles en la formación y el desarrollo de basidiomas. Durante la etapa reproductiva del hongo, las muestras se sometieron a un tratamiento de remojo. Sin embargo, no fue posible relacionar este tratamiento con el aumento de la producción de enzimas. Los niveles de actividad enzimática sugieren que la secreción de las enzimas estudiadas no influye en la capacidad de adaptación de las cepas al sustrato

Hydrolytic enzyme production (cellulases, laminarinases and xylanases) was studied in cultures of Lentinula edodes on sterilized coffee pulp. Samples of substrate colonized by mycelia were taken after 7, 14, 21, 28 and 35 days of incubation at 25°C (W1 to W5) and during the fruiting period at different stages: formation of primordia (PF), first harvest (H) and one week after the first harvest (PH). The enzymatic activity was lower during the early mycelial growth and showed higher levels during the formation and development of fruiting bodies. During the reproductive stage of the fungus, the samples were subjected to a soaking treatment; however, it was not possible to relate this soaking treatment to the increase in enzyme production. The levels of enzymatic activity suggest that secretion of the studied enzymes does not influence the adaptability of the strains to the substrate

Caracterização de fungos isolados da região Amazônica quanto ao potencial para produção das enzimas envolvidas na conversão da biomassa vegetal / Characterization of fungi isolated from the Amazon region for the potential of biomass-degrading enzymes production

A conversão da biomassa vegetal proveniente de resíduos agroindustriais e florestais em biocombustíveis e bioprodutos, dentro do conceito de biorrefinarias, é de grande interesse, principalmente para o Brasil, onde a agroenergia possui um enorme potencial de desenvolvimento. Entretanto, para garantir a viabilidade do processo de conversão, é fundamental reduzir o custo das enzimas utilizadas na etapa de hidrólise. Para isso, deve-se dispor da peça chave deste processo, que é o microrganismo. Nesse contexto, o objetivo deste trabalho foi avaliar fungos isolados da região Amazônica em relação ao potencial de produção das enzimas celulases e xilanases. De um total de 40 isolados cultivados por fermentação em estado sólido (FES), durante 10 dias, os fungos que se destacaram quanto à produção de endoglucanase (351,79Ug^-1 em 120h) e β-glicosidase (62,31Ug^-1em 72h) foi o P47C3 (A. niger), e na produção de xilanase (1076,94Ug^-1 em 72h) e FPase (2,46Ug^-1 em 120h) foram o P6B2 (A. oryzae) e o P40B3, respectivamente. Os resultados obtidos demonstram o enorme potencial de aplicação das enzimas produzidas pelos fungos isolados da Amazônia, contribuindo, assim, para gerar os avanços tecnológicos necessários para o aumento da eficiência do uso da biomassa vegetal como fonte de energia renovável

The conversion of biomass from forestry and agroindustrial residues into biofuels and bioproducts, within the biorefinery concept, is of great interest, especially to Brazil, where bioenergy has a huge potential for development. However, to ensure the viability of the conversion process it is essential to reduce the cost of the enzymes used in the hydrolysis step. For this, one must have the key element of this process, which is the microorganism. In this context, the objective of this study was to evaluate different fungi isolated from the Amazon region for their potential in terms of the production of cellulase and xylanase enzymes. Of a total of 40 strains cultivated under solid state fermentation (SSF) for 10 days, the strain that stood out for the production of endoglucanase (351.79Ug-1120h) and β-glucosidase (62.31Ug-1 at 72h) was P47C3 (A. niger) whereas for xylanase (1076.94Ug-1 in 72 hours) and FPase (2.46Ug-1 in120 hours) were P6B2 (A. oryzae) and P40B3, respectively. These results demonstrate the great potential application of the enzymes produced by the Amazon isolated fungi, thus contributing to generate the necessary technological advances in order to increase the efficiency of the use of biomass as a renewable energy source.

Purification and characterization of xylanases from Trichoderma inhamatum

Background Two xylanases, Xyl I and Xyl II, were purified from the crude extracellular extract of a Trichoderma inhamatum strain cultivated in liquid medium with oat spelts xylan. Results The molecular masses of the purified enzymes estimated by SDS-PAGE and gel filtration were, respectively, 19 and 14 kDa for Xyl I and 21 and 14.6 kDa for Xyl II. The enzymes are glycoproteins with optimum activity at 50°C in pH 5.0-5.5 for Xyl I and 5.5 for Xyl II. The xylanases were very stable at 40°C and in the pH ranges from 4.5-6.5 for Xyl I and 4.0-8.0 for Xyl II. The ion Hg2+ and the detergent SDS strongly reduced the activity while 1,4-dithiothreitol stimulated both enzymes. The xylanases showed specificity for xylan, Km and Vmax of 14.5, 1.6 mg·mL-1 and 2680.2 and 462.2 U·mg of protein-1 (Xyl I) and 10.7, 4.0 mg·mL-1 and 4553.7 and 1972.7 U·mg of protein-1 (Xyl II) on oat spelts and birchwood xylan, respectively. The hydrolysis of oat spelts xylan released xylobiose, xylotriose, xylotetrose and larger xylooligosaccharides. Conclusions The enzymes present potential for application in industrial processes that require activity in acid conditions, wide-ranging pH stability, such as for animal feed, or juice and wine industries.

Xylooligosaccharides: an economical prebiotic from agroresidues and their health benefits.

Oligosaccharides and dietary fibres are non-digestible food ingredients that preferentially stimulate the growth of prebiotic Bifidobacterium and other lactic acid bacteria in the gastro-intestinal tract. Xylooligosaccharides (XOS) provide a plethora of health benefits and can be incorporated into several functional foods. In the recent times, there has been an over emphasis on the microbial conversion of agroresidues into various value added products. Xylan, the major hemicellulosic component of lignocellulosic materials (LCMs), represents an important structural component of plant biomass in agricultural residues and could be a potent bioresource for XOS. On an industrial scale, XOS can be produced by chemical, enzymatic or chemo-enzymatic hydrolysis of LCMs. Chemical methods generate XOS with a broad degree of polymerization (DP), while enzymatic processes will be beneficial for the manufacture of food grade and pharmaceutically important XOS. Xylooligomers exert several health benefits, and therefore, have been considered to provide relief from several ailments. This review provides a brief on production, purification and structural characterization of XOS and their health benefits.

Screening of Fungal Resources for the Production of Cellulases and Xylanases.

Aims: The final screening of fungal isolates aimed at applications based tertiary screening i.e. deinking of mixed office waste paper and saccharification of pearl millet stover and cellulases from selected fungal isolates were characterized. Study Design: An experimental study. Methodology: Samples from soil, compost and decaying wood were collected from different habitats and were screened based on growth over CMC-agar medium (primary screening), zone ratios and enzyme activities (secondary screening) and applications such as bio-deinking of mixed office paper and saccharification of pearl millet stover (tertiary screening). Results: 134 fungal isolates were selected during primary screening based on their growth. In secondary screening, fungal strains showing zone ratio of 3.0 or more were selected for application based tertiary screening. Two fungal isolates AKB-24 and AKB-25 were selected based on their applications in deinking of mixed office waste and saccharification of pearl millet stover after tertiary screening. Fungal isolates AKB-25 and AKB-24 were identified as Aspergillus nidulans and Penicillium sp. Optimum pH for FPase, endoglucanase, and glucosidase activities were 5.0 for both the fungal strains. Cellulases from A. nidulans AKB-25 were found moderately thermo-stable with optimum endoglucanase activity at 65ºC and optimal FPase and β-glucosidase activities at 60ºC. The maximal endoglucanase, FPase and β-glucosidase activities were observed at 55ºC for fungal strain Penicillium sp. AKB-24. Cellulases from both fungal strains were found stable up to 48 h at 50ºC. Conclusion: Aspergillus nidulans AKB-25 and Penicillium sp. AKB-24 were selected based on an extensive screening and enzymes from both fungal strains were found effective in bio-deinking of mixed office waste paper. Enzyme from Aspergillus nidulans AKB-25 was also found effective in saccharification of pearl millet stover.

Characterization of cellulolytic activities of Bjerkandera adusta and Pycnoporus sanguineus on solid wheat straw medium / Caracterización de las actividades celulolíticas de Bjerkandera adusta y Pycnoporus sanguineus en un medio sólido de paja de trigo

Cellulolytic properties of two white rot fungi, Bjerkandera adusta and Pycnoporus sanguineus, cultivated on wheat straw agar medium, were characterized and compared. Optimal growing parameters for maximum enzyme production for both fungi were wheat straw medium pH 5 and 28ºC. B. adusta showed, on the 6th day of culture, carboxymethylcellulose (CMC)ase activity levels 1.6 times higher than maximal P. sanguineus activity, achieved on the 8th day. B. adusta supernatants also displayed higher activity levels towards xylan (3.6-fold) compared to those of P. sanguineus. However, enzymes from P. sanguineus were more robust resisting one hour incubation at high temperatures (up to 80ºC), and exhibiting activity and stability in pH range from 2 to 8. Cellulolytic activities, with molecular masses ranging from 25 to 90 kDa, from the two species were detected in zymograms.