Uma revisão sobre o potencial de co-culturas fúngicas na degradação de lignina
Data
2022-01-28
Autores
Soares, Jullio Kennedy Castro 
Orientadores
Vallim, Marcelo Afonso
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Atualmente a biomassa lignocelulósica corresponde a uma fonte de recurso altamente
abundante e renovável, porém, sendo pouca explorada devido à recalcitrância fornecida pelo
componente da lignina presente na parede vegetal, a qual pode ser superada pela degradação
por co-culturas fúngicas que gradativamente estão sendo estudadas devido a maior produção de
enzimas ligninolíticas, em detrimento das culturas axênicas, responsáveis pela modificação do
polímero. Devido a isto, o objetivo deste trabalho é compilar os estudos experimentais de
co-cultivos fúngicos na degradação da lignina e, para isto, foi adotado a metodologia de revisão
da literatura do tipo sistemática buscando em onze bases de dados e mecanismos de busca os
termos correspondente a este ramo de pesquisa para o levantamento de artigos científicos
relevantes, publicados virtualmente nas últimas três décadas, os quais foram verificados por
algumas etapas de triagem. Uma vez selecionados, os artigos científicos ainda foram
submetidos à técnica Bola de Neve para a otimização da recuperação de estudos relevantes.
Dentre os 43 estudos elegíveis que serviram de base para esta revisão, foi observado uma maior
frequência de co-culturas fúngicas consideradas neutras (54,5%) e sinérgicas (39,8%), seguido
dos raros co-cultivos antagônicos (5,7%), quanto à sua capacidade de degradar a lignina em
comparação aos respectivos cultivos axênicos. Em geral, o resultado do co-cultivo se
demonstra relacionado com o equilíbrio ou desbalanço dos efeitos antagônicos da
competição/estresse e efeitos sinérgicos das alterações fisiológicas favoráveis. Por mais que se
tenha conhecimento que as espécies pareadas, em conjunto com as condições microambientais
do sistema, sejam responsáveis pelas degradabilidades relatadas, os mecanismos moleculares
subjacentes às interações ainda permanecem incompreendidos. Além disso, também foi
acompanhada, em geral, frequências similares para os resultados dos co-cultivos fúngicos sobre
a degradação da holocelulose, decorrentes do aumento de enzimas hidrolíticas, e perda de
biomassa dos substrato, em relação às correspondentes culturas isoladas. Em suma, os achados
demonstram a aplicabilidade promissora de co-culturas fúngicas em setores biotecnológicos
que visam intensificar a degradação de lignina e seus derivados, mediante a sua melhor
compreensão em escala ecológica e industrial para a exploração de seu potencial biológico.
Currently, lignocellulosic biomass is a highly abundant and renewable resource source, however, it is little explored due to the recalcitrance provided by the lignin component present in the plant wall, which can be overcome by the degradation of fungal co-cultures that is gradually being studied due to greater production of ligninolytic enzymes, in comparison to axenic cultures, responsible for the polymer modification. Due to this, the objective of this research is to compile the experimental studies of fungal co-cultures in the degradation of lignin through a systematic literature review methodology, searching in eleven databases and search engines with the terms corresponding to this branch of research for the survey of relevant scientific articles, published virtually in the last three decades, which were verified by some screening steps. Once selected, the scientific articles were still submitted to the snowballing technique to optimize the retrieval of relevant studies. Among the 43 eligible studies that served as the basis for this review, a higher frequency of fungal co-cultures considered neutral (54.5%) and synergistic (39.8%) was observed, followed by rare antagonistic co-cultures (5, 7%), regarding their ability to degrade lignin compared to the respective axenic cultures. In general, the result of co-cultivation is shown to be related to the balance or unbalance of the antagonistic effects of competition/stress and synergistic effects of favorable physiological changes. As much as it is known that paired species, together with the microenvironmental conditions of the system, are responsible for the reported degradabilities, the molecular mechanisms underlying the interactions still remain to be understood. In addition, in general, similar frequencies were also monitored for the results of fungal co-cultures on holocellulose degradation, resulting from the increase in hydrolytic enzymes, and loss of substrate biomass, in relation to the corresponding monocultures. In short, the findings demonstrate the promising applicability of fungal co-cultures in biotechnological sectors that aim to intensify the degradation of lignin and its derivatives, through their better understanding on an ecological and industrial scale for the exploration of their biological potential.
Currently, lignocellulosic biomass is a highly abundant and renewable resource source, however, it is little explored due to the recalcitrance provided by the lignin component present in the plant wall, which can be overcome by the degradation of fungal co-cultures that is gradually being studied due to greater production of ligninolytic enzymes, in comparison to axenic cultures, responsible for the polymer modification. Due to this, the objective of this research is to compile the experimental studies of fungal co-cultures in the degradation of lignin through a systematic literature review methodology, searching in eleven databases and search engines with the terms corresponding to this branch of research for the survey of relevant scientific articles, published virtually in the last three decades, which were verified by some screening steps. Once selected, the scientific articles were still submitted to the snowballing technique to optimize the retrieval of relevant studies. Among the 43 eligible studies that served as the basis for this review, a higher frequency of fungal co-cultures considered neutral (54.5%) and synergistic (39.8%) was observed, followed by rare antagonistic co-cultures (5, 7%), regarding their ability to degrade lignin compared to the respective axenic cultures. In general, the result of co-cultivation is shown to be related to the balance or unbalance of the antagonistic effects of competition/stress and synergistic effects of favorable physiological changes. As much as it is known that paired species, together with the microenvironmental conditions of the system, are responsible for the reported degradabilities, the molecular mechanisms underlying the interactions still remain to be understood. In addition, in general, similar frequencies were also monitored for the results of fungal co-cultures on holocellulose degradation, resulting from the increase in hydrolytic enzymes, and loss of substrate biomass, in relation to the corresponding monocultures. In short, the findings demonstrate the promising applicability of fungal co-cultures in biotechnological sectors that aim to intensify the degradation of lignin and its derivatives, through their better understanding on an ecological and industrial scale for the exploration of their biological potential.