An exploration of the ligninolytic potential of lignocellulolytic microbial consortia can improve our understanding of the eco-enzymology of lignin conversion in nature. In this study, we aimed to detect enriched lignin-transforming enzymes on metagenomes from three soil-derived microbial consortia that were cultivated on “pre-digested” plant biomass (wheat straw, WS1-M; switchgrass, SG-M; and corn stover, CS-M). Of 60 selected enzyme-encoding genes putatively involved in lignin catabolism, 20 genes were significantly abundant in WS1-M, CS-M, and/or SG-M consortia compared with the initial forest soil inoculum metagenome (FS1). These genes could be involved in lignin oxidation (e.g., superoxide dismutases), oxidative stress responses (e.g., catalase/peroxidases), generation of protocatechuate (e.g., vanAB genes), catabolism of gentisate, catechol and 3-phenylpropionic acid (e.g., gentisate 1,2-dioxygenases, muconate cycloisomerases, and hcaAB genes), the beta-ketoadipate pathway (e.g., pcaIJ genes), and tolerance to lignocellulose-derived inhibitors (e.g., thymidylate synthases). The taxonomic affiliation of 22 selected lignin-transforming enzymes from WS1-M and CS-M consortia metagenomes revealed that Pseudomonadaceae, Alcaligenaceae, Sphingomonadaceae, Caulobacteraceae, Comamonadaceae, and Xanthomonadaceae are the key bacterial families in the catabolism of lignin. A predictive “model” was sketched out, where each microbial population has the potential to metabolize an array of aromatic compounds through different pathways, suggesting that lignin catabolism can follow a “task division” strategy. Here, we have established an association between functions and taxonomy, allowing a better understanding of lignin transformations in soil-derived lignocellulolytic microbial consortia, and pinpointing some bacterial taxa and catabolic genes as ligninolytic trait-markers.

探索木质纤维素分解微生物聚生体的木质素分解潜力可以增进我们对自然界中木质素转化的生态酶的理解。在这项研究中，我们旨在检测在“预先消化”的植物生物量（小麦秸秆，WS1-M；柳枝,、 SG-M和玉米秸秆）上培育的三个土壤微生物群落的基因组中富集的木质素转化酶。 ，CS-M）。与最初的森林土壤接种物元基因组（FS1）相比，在60个被选为可能参与木质素分解代谢的酶编码基因中，WS1-M，CS-M和/或SG-M群体中有20个基因显着丰富。这些基因可能参与木质素的氧化（例如超氧化物歧化酶），氧化应激反应（例如过氧化氢酶/过氧化物酶），原儿茶酸的产生（例如vanAB基因），龙胆酸酯，儿茶酚和3-苯基丙酸（例如，龙胆酸酯1,2-双加氧酶，粘康酸酯环异构酶和hca AB基因）的分解代谢，β-酮己二酸酯途径（例如pca）IJ基因），以及对木质纤维素衍生抑制剂（例如胸苷酸合酶）的耐受性。来自WS1-M和CS-M财团的基因组的22种选定的木质素转化酶的分类学隶属关系表明，假单胞菌科，拟南芥科，Sphingomonadaceae，Caulobacteraceae，Comamonadaceae和Xanthomonadaceae是木质素分解代谢中的关键细菌家族。勾画出一种预测性的“模型”，其中每个微生物种群都有可能通过不同途径代谢一系列芳香化合物，这表明木质素分解代谢可以遵循“任务划分”策略。在这里，我们建立了功能与分类法之间的关联，从而可以更好地了解土壤衍生的木质纤维素分解微生物群落中木质素的转化，