Composição funcional e taxonômica de enzimas carbohidrases que atuam na desconstrução da lignocelulose de torta de filtro
Carregando...
Arquivos
Data
2018-02-07
Autores
Omori, Wellington Pine [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A torta de filtro apresenta bagaço residual oriundo do processo de extração do caldo de cana-de-açúcar e quando armazenada por longos períodos, se torna um habitat ideal para o desenvolvimento de comunidades microbianas que atuam na desconstrução da lignocelulose. Nossas análises de dados de sequenciamento de DNA metagenômico sugerem que a torta de filtro armazenada por 40 dias possui uma microbiota com características funcionais e ecológicas exclusivas em relação a outros ambientes com elevada disposição de material lignocelulósico. Assim como em ambientes de compostagem, os filos mais abundantes são Actinobacteria, Proteobacteria, Firmicutes e Bacteroidetes. Dentre os principais genes que estes micro-organismos possuem, estão Glicosiltransferases, Carboidrato Esterases e Glicosil Hidrolases, que atuando em conjunto, são passíveis de desconstruírem a lignocelulose e participarem na liberação de açúcares menores, ácidos orgânicos e outros nutrientes. Neste trabalho, identificamos novas enzimas da família AA10 que oxidam a celulose cristalina, demostrando o potencial deste ambiente em possibilitar a adaptação de micro-organismos que expressam enzimas capazes de desestruturar a celulose altamente condensada, possibilitando a liberação de moléculas de glicose. A comunidade microbiana pode acessar nutrientes como Fósforo e Nitrogênio através da despolimerização da biomassa vegetal ou decomposição da microbiota morta. No ciclo biogeoquímico do nitrogênio, a evaporação de amônia é reduzida pela assimilação desta substância pela comunidade microbiana, sendo que a amônia é produzida pela via de amonificação de nitrato e nitrito. Outro ciclo biogeoquímico identificado na torta de filtro foi o do carbono, ocorrendo diminuição da emissão de metano e gás carbônico devido ao uso destas moléculas no metabolismo microbiano. Por apresentar muitas espécies de micro-organismos termofílicos e funções ecológicas similares a compostagens que alcançaram fase termofílica, a torta de filtro armazenada por 40 dias não aparenta conter micro-organismos patogênicos em elevada abundância, o que poderia ser um indício de sua segurança biológica se usado como adubo no solo. No entanto, recomenda-se que novos estudos sejam realizados neste tipo de ambiente agrícola, afim de avaliar como se comportam principalmente os fungos Neosartorya fumigata e Paracoccidioides brasiliensis, os quais são identificados como agentes patogênicos mas que também são encontrados vivendo na natureza como organismos saprofíticos e em interação com alguns mamíferos, sem causar doença.
The filter cake presents residual bagasse from the process of extracting the sugarcane juice and when stored for long periods, it becomes an ideal habitat for the development of microbial communities that act in the deconstruction of lignocellulose. Our analyzes of metagenomic DNA sequencing data suggest that the filter cake stored for 40 days has a microbiota with unique functional and ecological characteristics compared to other environments with high lignocellulosic material. Thus in composting environments, the most abundant phyla are Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes. Glycosyltransferases, Carbohydrate Estersases and Glycoside Hydrolases, which act together, are capable of deconstructing lignocellulose and participate in the release of smaller sugars, organic acids and other nutrients. In this work, we identify new enzymes of the AA10 family that oxidize crystalline cellulose, demonstrating the potential of this environment to enable the adaptation of microorganisms that express enzymes capable of destabilizing highly condensed cellulose, allowing the release of glucose molecules. The microbial community can access nutrients such as Phosphorus and Nitrogen through the depolymerization of the plant biomass or decomposition of the dead microbiota. In the biogeochemical cycle of nitrogen, the evaporation of ammonia is reduced by the assimilation of this substance by the microbial community, and ammonia is produced by ammonification of nitrate and nitrite. Another biogeochemical cycle identified in the filter cake was that of carbon, with a decrease in the emission of methane and carbon dioxide due to the use of these molecules in microbial metabolism. Because it contains many species of thermophilic microorganisms and ecological functions similar to composting that reached the thermophilic phase, the filter cake stored for 40 days does not appear to contain pathogenic microorganisms in high abundance, which could be an indication of its biological safety if used as soil fertilizer. However, it is recommended that new studies be carried out in this type of agricultural environment, in order to evaluate the behavior of the fungi Neosartorya fumigata and Paracoccidioides brasiliensis, which are identified as pathogens but are also found living in nature as saprophytic organisms and in interaction with some mammals, without causing disease.
The filter cake presents residual bagasse from the process of extracting the sugarcane juice and when stored for long periods, it becomes an ideal habitat for the development of microbial communities that act in the deconstruction of lignocellulose. Our analyzes of metagenomic DNA sequencing data suggest that the filter cake stored for 40 days has a microbiota with unique functional and ecological characteristics compared to other environments with high lignocellulosic material. Thus in composting environments, the most abundant phyla are Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes. Glycosyltransferases, Carbohydrate Estersases and Glycoside Hydrolases, which act together, are capable of deconstructing lignocellulose and participate in the release of smaller sugars, organic acids and other nutrients. In this work, we identify new enzymes of the AA10 family that oxidize crystalline cellulose, demonstrating the potential of this environment to enable the adaptation of microorganisms that express enzymes capable of destabilizing highly condensed cellulose, allowing the release of glucose molecules. The microbial community can access nutrients such as Phosphorus and Nitrogen through the depolymerization of the plant biomass or decomposition of the dead microbiota. In the biogeochemical cycle of nitrogen, the evaporation of ammonia is reduced by the assimilation of this substance by the microbial community, and ammonia is produced by ammonification of nitrate and nitrite. Another biogeochemical cycle identified in the filter cake was that of carbon, with a decrease in the emission of methane and carbon dioxide due to the use of these molecules in microbial metabolism. Because it contains many species of thermophilic microorganisms and ecological functions similar to composting that reached the thermophilic phase, the filter cake stored for 40 days does not appear to contain pathogenic microorganisms in high abundance, which could be an indication of its biological safety if used as soil fertilizer. However, it is recommended that new studies be carried out in this type of agricultural environment, in order to evaluate the behavior of the fungi Neosartorya fumigata and Paracoccidioides brasiliensis, which are identified as pathogens but are also found living in nature as saprophytic organisms and in interaction with some mammals, without causing disease.
Descrição
Palavras-chave
Actinobacteria, Archaea, Atividades Auxiliares (AAs), Bioetanol, Celulose cristalina, Hemicelulose, Auxiliary Activities (AAs), Bioethanol, Crystalline cellulose, Hemicellulose