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. A random combination of six isolates and two purchased strains was constructed to obtain LXB, the degradation of lignocellulose resulted in a 40.6% after 168 hours. A total of 1872 genes that were differentially expressed and involved in the degradation of lignocellulose in LXB have been identified in the Carbohydrate-Active enZYmes Database. Genes that encode cellulases and hemicellulase were expressed in abundance, the gene that encodes hemicellulase displaying highest expression at the initial and peak stages of degradation. Considerable increase in gene expression of Versatile peroxidase and coenzyme Alcohol oxidase involved in lignin catabolism. LXB catalyzes the breakdown of lignocellulose mainly through six pathways in the carbohydrate metabolic pathway, catechol was discovered in the benzoate degradation pathway, which participates in the degradation of lignin. Additionally, LXB possesses the capability to degrade harmful exogenous substances.

木质纤维素生物质的生物降解是一种实用且高效的处理手段。本研究通过将6株分离菌株与2株购买菌株随机组合，构建得到降解菌系LXB；该菌系在168小时内对木质纤维素的降解率可达40.6%。在碳水化合物活性酶（Carbohydrate-Active enZYmes, CAZy）数据库中，已鉴定出LXB中1872个与木质纤维素降解相关的差异表达基因。编码纤维素酶与半纤维素酶的基因表达量较高，其中编码半纤维素酶的基因在降解初始阶段与峰值阶段均呈现最高表达水平。参与木质素分解代谢的多功能过氧化物酶（Versatile peroxidase）与醇氧化酶的基因表达量显著上调。LXB主要通过碳水化合物代谢通路中的6条途径催化木质纤维素的降解；在苯甲酸降解通路中发现的邻苯二酚（catechol）参与了木质素的降解过程。此外，LXB还具备降解有害外源性物质的能力。