Abstract：
Lignin is an aromatic macromolecule and one of the main constituents of lignocellulosic materials. Kraft lignin is generated as a residual by-product of the lignocellulosic biomass industrial process, and it might be used as a feedstock to generate low molecular weight aromatic compounds. In this study, we seek to understand and explore the potential of ruminal bacteria in the degradation of kraft lignin. We established two consortia, KLY and KL, which demonstrated significant lignin-degrading capabilities. Both consortia reached maximum growth after two days, with KLY showing a higher growth and decolorization rate. Additionally, SEM analysis revealed morphological changes in the residual lignin from both consortia, indicating significant degradation. This was further supported by FTIR spectra, which showed new bands corresponding to the C-H vibrations of guaiacyl and syringyl units, suggesting structural transformations of the lignin. Taxonomic analysis showed enrichment of the microbial community with members of the Dickeya genus. Seven metabolic pathways related to lignin metabolism were predicted for the established consortia. Both consortia were capable of consuming aromatic compounds such as 4-hydroxybenzoic acid, syringaldehyde, acetovanillone, and syringic acid, highlighting their capacity to convert aromatic compounds into commercially valuable molecules presenting antifungal activity and used as food preservatives as 4-hydroxyphenylacetic, 3-phenylacetic, and phenylacetic acids. Therefore, the microbial consortia shown in the present work are models for understanding the process of lignin degradation and consumption in bacterial anaerobic communities and developing biological processes to add value to industrial processes based on lignocellulosic biomass as feedstock.
摘要：
木质素是一种芳香族高分子,是木质纤维素材料的主要成分之一。硫酸盐木质素是作为木质纤维素生物质工业过程的残余副产物产生的。并且它可以用作原料以产生低分子量的芳族化合物。在这项研究中,我们试图了解和探索瘤胃细菌在硫酸盐木质素降解中的潜力。我们成立了两个财团,KLY和KL,表现出显著的木质素降解能力。两个财团在两天后达到最大生长，与KLY表现出更高的生长和脱色率。此外,SEM分析揭示了来自两个聚生体的残余木质素的形态变化，表明显著降解。这得到了FTIR光谱的进一步支持，显示出对应于愈创酰基和丁香酰基单元的C-H振动的新条带，表明木质素的结构转变。分类学分析显示，Dickeya属成员的微生物群落富集。对于已建立的聚生体，预测了与木质素代谢相关的七个代谢途径。两个财团都能够消耗芳香族化合物，如4-羟基苯甲酸，丁香醛,乙酰苯胺,和丁香酸,突出了它们将芳香族化合物转化为具有抗真菌活性的有商业价值的分子的能力，并用作食品防腐剂作为4-羟基苯乙酸，3-苯基乙酸,和苯乙酸.因此,本工作中显示的微生物聚生体是用于理解细菌厌氧群落中木质素降解和消耗过程以及开发生物过程以增加基于木质纤维素生物质作为原料的工业过程的价值的模型。
