Screening of cellulose-degrading bacteria and its degradation and growth-promoting applications.

More than one billion tons of chaff waste are generated globally every year, but traditional recycling methods face the dual challenges of inefficiency and environmental risks, to solve this problem, this study innovatively achieves the dual functions of lignocellulosic synergistic degradation and plant promotion by constructing synthetic microbial communities. Firstly, a cellulose-degrading bacterium cmk-7 (Chromobacterium violaceum) was screened from soil based on Congo red staining method, and the maximum values of CMCase enzyme activity and FPase enzyme activity were 289.12 and 332.95 U/mL, respectively, and the culture conditions of cellulose-degrading bacteria were optimized by single factor test and response surface experiment, and its production intensity was increased by 2.43 times, respectively. Subsequently, cellulose-degrading bacteria were mixed with nitrogen-fixing bacterium Enterobacter tabaci lmy-3-2 in a 1:1 ratio to prepare a composite bacterial agent A7 to treat rice husks for potting experiments and seedling experiments. After 80 days of fermentation, the surface structure of rice husk, the soil microbial community structure was significantly reconstructed, and the ratio of carbon and nitrogen content in the soil was changed, and the plant height growth of the compound agent A7 treatment group increased by 96.5% and 193.9%, respectively, compared with the Sterile water treatment and nitrogen-fixing single bacteria treatment group, which effectively promoted the growth of buckwheat seedlings. In this study, the triple effect coupling of "solid waste degradation-soil improvement-crop growth" was successfully realized, and a mass-produced microbiome solution was provided for the agricultural circular economy, with broad application prospects. One-Sentence Summary: The cellulose-degrading bacterium cmk-7 was screened and optimized to make a compound microbial agent with nitrogen-fixing bacterium lmy-3-2, which could promote chaff degradation and crop growth.