耐低温降解木质纤维素芽孢杆菌的筛选及性质研究OA

[Objective]In order to address the issue of low resource utilization efficiency of lignocellulose-like biomass under low-tem-perature conditions,this study was conducted to screen Bacillus strains that can degrade lignocellulose at low temperatures.[Methods]The fresh fecal samples of Protaetia brevitarsis were collected from the breeding base of Protaetia brevitarsis at Xianxian Qiujiang co-operative in Hebei Province.Following the isolation,primary screening,and secondary screening of strains,the obtained isolates were subjected to species identification via morphological analysis,16S rDNA sequence analysis,and physiological and biochemical charac-terization assays.Additionally,their cellulase activities were determined under different temperature and pH conditions.[Results]Five lignocellulose-degrading strains were isolated and screened from the feces of Protaetia brevitarsis,named Bacillus tequilensis N5-2,Bacillus amyloliquefaciens Y5-3,Bacillus subtilis R4-3,Bacillus siamensis N3-5,and Bacillus vallismortis R4-4.The cellulase ac-tivities of R4-3 and R4-4 exhibited a slow decline with decreasing temperature.Specifically,the cellulase activity of R4-3 remained above 80 U/mL even at 20 ℃,and could also reach 80 U/mL at pH 4.0.[Conclusion]Five low-temperature-resistant Bacillus strains that produce lignocellulase were isolated.Among them,Bacillus subtilis R4-3 strain could grow at 10℃and pH 3.5,and grew well at 20℃and pH 4.0,with cellulase activity reaching about 80 U/mL,which provided strain resources for the efficient utilization of agri-cultural and forestry waste in northern winter.