Microbial decomposition of rice straw: alkaline pretreatment, genome analysis and fermentation broth on seed growth

The rich cellulose in rice straw is an obstacle to the resource utilization of rice straw. It is difficult to degrade cellulose only by biodegradation, chemical or physical degradation. The weight loss rate of rice straw reached 38.86% by the inoculation of Bacillus amyloliquefaciens N5 combined with alkali pretreatment. The fermentation broth of strain N5 and straw could promote the rice seed’s germination and the growth of rice seedlings. Moreover, the addition of peptone as a nutrient source further amplified the cellulose degradation. The whole genome analysis revealed genes associated with cellulose degradation in the genome of strain N5, including glycoside hydrolase family 1 (GH1), GH13, GH43, and three polysaccharide lyases (PLs), eleven carbohydrate esterases (CEs), twenty-six glycosyltransferases (GTs), and twenty-five carbohydrate-binding modules (CBMs).