Triagem de fungos filamentosos para degradação de lignina: avaliação da atividade ligninolítica e da enzima lacase
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Data
2023-03-03
Autores
Toneti, Matheus Henrique
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Universidade Estadual Paulista (Unesp)
Resumo
A utilização de recursos fósseis e fontes de carbono não-renováveis para a obtenção de produtos químicos e energia mostrou, por inúmeros estudos, ter impactos negativos significativos no que diz respeito a aspectos ambientais e socioeconômicos para a sociedade. Por outro lado, a utilização de biomassa vegetal para a obtenção de biocompostos e bioenergia tem ganhado cada vez mais espaço e vem recebendo a atenção e investimentos devido ao seu potencial econômico e sustentável. A obtenção de biocompostos se dá principalmente pela ação de enzimas produzidas por microrganismos que, após degradar o substrato derivado de biomassa vegetal, são capazes de liberar moléculas de alto valor agregado. O objetivo deste trabalho foi avaliar o potencial de duas espécies de fungos filamentosos (Trichoderma harzianum Rifai PAMB-86 e Coriolopsis byrsina SXS16) em degradar lignina e produzir compostos de alto valor agregado. O substrato utilizado foi o licor obtido por hidrólise alcalina de bagaço-de-cana, mistura rica em lignina e hemicelulose. A fermentação foi suplementada com vinhaça e com meio mineral, e os resultados obtidos foram comparados. A degradação da lignina foi estimada pela absorbância no comprimento de onda de 280 nm e os resultados foram promissores: após os 10 dias, mais de 50% de degradação foi observada para as espécies Trichoderma harzianum e Coriolopsis byrsina em meio contendo vinhaça e cerca de 70% para meio contendo solução mineral. Além disso, foi confirmada a possibilidade da utilização de vinhaça, um subproduto da indústria sucroalcooleira, como suplemento para o crescimento dos microrganismos, visto que os resultados obtidos se assemelham, e em alguns casos são superiores aos experimentos utilizando solução mineral como suplemento. Outros parâmetros também foram monitorados: o pH do meio, que aumentou com relação ao controle abiótico, confirmando a liberação de compostos básicos; e a atividade da enzima lacase que alcançou valores próximos de 100 µmol.min-1 para o Trichoderma harzianum e 50 µmol min-1 para o Coriolopsis byrsina no meio suplementado com meio mineral. Por outro lado, no meio suplementado com vinhaça não se observou atividade dessa enzima. Por fim, confirmou-se que o crescimento microbiano das cepas no meio de cultivo contendo o licor ocorreu de forma satisfatória e promissora, abrindo espaço para novas pesquisas envolvendo esses microrganismos para a produção de compostos de valor agregado.
Numerous studies have proven that using fossil fuels and non-renewable carbon sources to produce chemical feedstocks and energy has serious detrimental effects on the environment and the economy. On the other hand, due to its potential for economic growth and sustainability, the use of vegetal biomass to produce biocompounds and bioenergy has drawn increased attention. Biocompounds are primarily obtained through the intricate enzymatic activity of microbes, which, after breaking down the substrate produced from plant biomass, are able to release molecules with significant added value. The main objective of this work was to evaluate the potential of two species of filamentous fungi (Trichoderma harzianum Rifai PAMB-86 and Coriolopsis byrsina SXS16) to degrade lignin and produce compounds with high added value. The sugarcane bagasse liquor produced by the alkaline hydrolysis of this mixture, which is high in lignin and hemicellulose, served as the study's substrate. Vinasse and mineral medium were added to the fermentation process, and the outcomes were compared. The rate of lignin degradation was calculated using absorbance at 280 nm, and the results were encouraging: after 10 days, the species Trichoderma harzianum and Coriolopsis byrsina had degraded more than 50% of the lignin in vinasse media and about 70% in mineral media. The use of vinasse, a byproduct of the sugar-alcohol industry, as a supplement for the growth of microorganisms was also proven, since the results were comparable to and occasionally even superior to those achieved using only mineral solution. The pH of the medium, which increased in comparison to the abiotic control, confirming the release of basic compounds, and the laccase enzyme activity, which for Trichoderma harzianum and Coriolopsis byrsina in the medium supplemented with mineral medium reached values close to 100 mol min-1 and 50 mol min-1, respectively, were also monitored. On the other hand, this enzyme's activity was not maintained in the medium enriched with vinasse. Finally, it was determined that the strains' microbial development in the culture medium containing the liquor proceeded adequately and in a promising manner, opening the door for further investigation into these microbes for the manufacture of chemicals with value-added.
Numerous studies have proven that using fossil fuels and non-renewable carbon sources to produce chemical feedstocks and energy has serious detrimental effects on the environment and the economy. On the other hand, due to its potential for economic growth and sustainability, the use of vegetal biomass to produce biocompounds and bioenergy has drawn increased attention. Biocompounds are primarily obtained through the intricate enzymatic activity of microbes, which, after breaking down the substrate produced from plant biomass, are able to release molecules with significant added value. The main objective of this work was to evaluate the potential of two species of filamentous fungi (Trichoderma harzianum Rifai PAMB-86 and Coriolopsis byrsina SXS16) to degrade lignin and produce compounds with high added value. The sugarcane bagasse liquor produced by the alkaline hydrolysis of this mixture, which is high in lignin and hemicellulose, served as the study's substrate. Vinasse and mineral medium were added to the fermentation process, and the outcomes were compared. The rate of lignin degradation was calculated using absorbance at 280 nm, and the results were encouraging: after 10 days, the species Trichoderma harzianum and Coriolopsis byrsina had degraded more than 50% of the lignin in vinasse media and about 70% in mineral media. The use of vinasse, a byproduct of the sugar-alcohol industry, as a supplement for the growth of microorganisms was also proven, since the results were comparable to and occasionally even superior to those achieved using only mineral solution. The pH of the medium, which increased in comparison to the abiotic control, confirming the release of basic compounds, and the laccase enzyme activity, which for Trichoderma harzianum and Coriolopsis byrsina in the medium supplemented with mineral medium reached values close to 100 mol min-1 and 50 mol min-1, respectively, were also monitored. On the other hand, this enzyme's activity was not maintained in the medium enriched with vinasse. Finally, it was determined that the strains' microbial development in the culture medium containing the liquor proceeded adequately and in a promising manner, opening the door for further investigation into these microbes for the manufacture of chemicals with value-added.
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Lignina, Biodegradação, Fungos, Lignin, Biodegradation, Fungi