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.

A method for seedling recovery in Jatropha curcas after cryogenic exposure of the seeds

Actually, the germplasm of Jatropha spp. is conserved as whole plants in field collections. Under this storage method, the genetic resources are exposed to disease, pest and natural hazards such as human error, drought and weather damage. Besides, field genebanks are costly to maintain and with important requirements of trained personnel. Thus, the development of efficient techniques to ensure its safe conservation and regeneration is therefore of paramount importance. In this work we describe a method for Jatropha curcas seeds cryoexposure and seedling recovery after thawed. In a first experiment, an efficient protocol for in vitro plant recovery was carried out using zygotic embryo or seeds with or without coat. In a second experiment, desiccated seeds with or without coat were exposed to liquid nitrogen and evaluated after cryoexposure. Germination percentages were variable among treatments, and seeds demonstrated tolerance to liquid nitrogen exposure under certain conditions. Seeds of J. curcas presented up to 99.6% germination after seed coat removal. Seeds with coat cultured in vitro did not germinate, and were 60% contaminated. The germination of the zygotic embryos was significantly higher in the ½ MS medium (93.1%) than in WPM medium (76.2%), but from zygotic embryo, abnormal seedlings reached up to 99%. Seeds with coat exposed to liquid nitrogen showed 60% germination in culture after coat removal with good plant growth, and seeds cryopreserved without coat presented 82% germination, but seedlings showed a reduced vigor and a significant increase in abnormal plants. Seeds cultured in vitro with coat did not germinate, independently of cryoexposure or not. This study reports the first successful in vitro seedling recovery methodology for Jatropha curcas seeds, after a cryopreservation treatment, and is recommended as an efficient procedure for in vitro plant recovery, when seeds are conserved in germplasm banks by low or cryotemperatures.

Actualmente, el germoplasma de las especies de Jatropha ssp. se conserva como plantas enteras en las colecciones de campo. Bajo este método de almacenamiento, los recursos genéticos están expuestos a enfermedades, plagas y desastres naturales tales como el error humano, la sequía y las inclemencias del tiempo. Además, los bancos de germoplasma de campo son costosos de mantener y requieren bastante personal capacitado. Por lo tanto, el desarrollo de técnicas eficientes para asegurar su conservación segura así como su regeneración, es de suma importancia. En este trabajo se describe un método de recuperación para semillas y plántulas crioexpuestas de Jatropha curcas después de descongeladas. En un primer experimento, se llevó a cabo un protocolo eficiente para la recuperación de plantas in vitro mediante el uso de embriones cigóticos o semillas con o sin testa. En un segundo experimento, las semillas disecadas, con o sin testa fueron expuestas a nitrógeno líquido y se evaluaron después de la crioexposición. Los porcentajes de germinación fueron variables entre los tratamientos, y las semillas demostraron tolerancia a la exposición del nitrógeno líquido bajo ciertas condiciones. Las semillas de J. curcas presentaron hasta un 99.6% de germinación después de la eliminación de la testa. Las semillas con la testa cultivadas in vitro no germinaron, y el 60% se contaminaron. La germinación de los embriones cigóticos fue significativamente alta en el medio ½ MS (93.1%) en comparación con el medio WPM (76.2%), pero desde los embriones zigóticos, las plántulas anormales alcanzaron más del 99%. Semillas con la testa inmersa en nitrógeno líquido mostraron un 60% de germinacion en cultivos despúes de la remoción de la testa con un buen crecimiento de la planta, y las semillas criopreservadas sin testa presentaron un 82% de germinación, pero las plántulas mostraron un reducido vigor y un incremento significativo de plantas anormales. Semillas con testa cultivadas in vitro no germinaron, independientemente de la criopreservación o no. Este estudio reporta el primer éxito in vitro de una metodología de recuperación de plántulas para semillas de Jatropha curcas, después de un tratamiento de criopreservación, que se recomienda como un procedimiento eficaz para la recuperación de plantas in vitro, cuando las semillas se conservan en bancos de germoplasma a bajas o crio-temperaturas.