Characteristics and functional bacteria in a microbial consortium for rice straw lignin-degrading.

The degradation of lignin is the main rate-limiting step in the bio-pulping of rice straw. A lignin-degrading bacterial consortium LDC, which can efficiently degrade lignin of reed, was screened in the early stage of our laboratory work. In present study, 7-day incubation of LDC can degrade rice straw lignin by 31.18% in mineral salt medium. The communities' structure of different incubation phases varied greatly, in which high abundance (44.78%) of Anaerocolumna was first found. The expression levels of lignin degradation enzyme class II peroxidase (AA2), vanillyl alcohol oxidase (AA4) and 1,4-benzoquinone reductase (AA6) during peak phase (48 h) were significantly up-regulated than initial phase (24 h), increasing by 112%, 165% and 67%, respectively, and 42.86% AA2 was from Thaurea; 100% AA4 was from Clostridium; 62.5% AA6 was from Pseudomonas. These provide microbial resources and data support for the industrialization of rice straw bio-pulping.