Functional enzyme analysis and metabolic regulation mechanism of the combined microflora LXB in the degradation of lignocellulose

The biodegradation of lignocellulosic biomass is a practical and effective method to enhance renewable energy utilization. Six strains were isolated from various organic sources, exhibiting higher enzymatic performance on lignocellulose, and the most effective combined microflora LXB was constructed. In the process of using LXB for the degradation of lignocellulose, it was observed that the degradation rate reached 46.1% after 168 hours. The enzyme classes that were encoded by the genes involved in lignocellulose degradation in LXB were identified in the Carbohydrate-Active enZYmes Database. Expression of genes encoding Endo-beta-1,4-glucanase, Cellobiohydrolase, beta-glucosidase, and Lytic polysaccharide monooxygenase increased by 6.5 to 12.1folds, resulting in substantial degradation of cellulose. Ten enzymes collectively participate in the degradation of hemicellulose, with the gene that encodes hemicellulase displaying heightened expression at the initial and peak stages of degradation. The expression of genes encoding the major degradation enzymes, Manganese peroxidase and Versatile peroxidase, increased by 5.8 and 29.0 folds, among the enzymes linked to lignin breakdown, and the expression of genes encoding the coenzyme Alcohol oxidase increased up to 16.7 folds. LXB catalyzes the breakdown of lignocellulose mainly via the starch and sucrose metabolism, amino sugar and nucleotide sugar metabolism. Additionally, it possesses the capability to degrade harmful exogenous substances.