关键词: 木质纤维素, 贝莱斯芽孢杆菌（Bacillus velezensis）, 降解, 烟梗

Abstract: In order to reduce the content of lignocellulose in tobacco stems and solve the problem of low industrial use value, bacteria with potential for degradation of tobacco stem lignocellulose were screened. A cellulase screening medium was used to isolate a tobacco lignocellulose-degrading strain HF-09 from tobacco cultivation soil in Kunming city. After morphological observation and physiological and biochemical analysis, combined with 16S rRNA sequencing and phylogenetic analysis, the strain was identified as Bacillus velezensis. The survival rate of the bacterium was above 90% in the range of pH 5~9 or below 75 ℃, and it reached the logarithmic growth phase in 8~20 h, which had strong adaptability. After 10-day degradation of tobacco stems of Hongda （C3F）, the cellulose degradation rate was 20.82%, the hemicellulose degradation rate was 30.28%, and the lignin degradation rate was 19.34%. At the same time, scanning electron microscopy showed that the bacteria had a significant ability to damage the structure of tobacco stems.

Key words: lignocellulosic, Bacillus velezensis, degradation, tobacco stem