A novel lignin degradation bacteria-Bacillus amyloliquefaciens SL-7 used to degrade straw lignin efficiently.

• The first report on tobacco straw lignin degradation by bacterium of genus Bacillus. • Bacillus amyloliquefaciens SL-7 secreted Lip, MnP and Lac to degrade lignin. • The practical application effect of this strain on tobacco straw compost was explored. Using tobacco straw (Ts) and lignin as the sole carbon source, a strain was isolated from Ts and identified as Bacillus amyloliquefaciens SL- 7 by 16S rDNA gene-sequencing technology.7-day incubation of Bacillus amyloliquefaciens SL- 7 can reduce the chemical oxygen demand (COD) by 69.35% in lignin mineral salt medium. The activity of Manganese peroxidase (MnP) reached maximum level 258.57 U L−1, and Lignin peroxidase (Lip) was 422.68 U L−1 at 4th day. The highest Laccase (Lac) activity (55.95 U L−1) was observed at 3th day. After straw-liquid fermentation degradation of 15 days, the bacterial could degrade 28.55% lignin of the straw which was close to that of fungi. Compared with the control group and effective microorganisms (EM) group, the lignin degradation rate in Bacillus amyloliquefaciens SL-7 group increased by 22.26% and 11.70% at 41-day compost fermentation of tobacco straw. These show the strain has strong lignin degradation performance. [ABSTRACT FROM AUTHOR]