华北地区圈养大熊猫粪便中产纤维素酶芽孢杆菌菌株的分离与鉴定

Isolation and identification of Bacillus capable of degrading cellulose from the feces captive giant panda of in north China

为分离筛选大熊猫肠道中具有纤维素降解能力的芽孢杆菌菌株,首先对8份大熊猫粪便进行高温水浴处理,利用刚果红平板法进行初筛和复筛,DNS法测定酶活力.结果分离出126株菌株,其中8株菌株纤维素降解能力较强.结合形态特征、生理生化特征和16SrDNA序列分析,鉴定8个菌株均属于芽孢杆菌属,其中1株枯草芽孢杆菌(Bacillus subtilis),1株阿萨尔基芽孢杆菌(B.axarquienis),2株西姆芽孢杆菌(B.siamensis),4株甲基营养型芽孢杆菌(B.methylotrophicus).实验表明大熊猫肠道中存在多种降解纤维素的芽孢杆菌,其中新发现的有大熊猫源的阿萨尔基芽孢杆菌和西姆芽孢杆菌,丰富了大熊猫肠道菌群的研究,并为高效生产纤维素酶提供新的菌种来源.探究了大熊猫消化道内高效的纤维素降解菌,有利于实现高纤维类饲料资源化利用.

This study aimed at screening strains of Bacillus sp.capable of degrading cellulose and identifying the species of purpose strains.8dung samples of giant panda were treated in water bath at high temperature.Congo red decolorizing ring method was used to screen the strains before DNS method to test the highest enzyme activity.The results showed that 8strains of 126 strains isolated in dung of giant panda had highly efficient cellulose-degrading capability.Through morphological,physiological and biochemical analysis and the sequence analysis of 16 SrDNA gene,8strains were identified.The strains are all Bacillus sp.,including 1 Bacillus subtilis（2N-14）,1 B.axarquienis（2N-12）,2 B.siamensis（Y-6、Y-10）,and 4 B.methylotrophicus（2N-10、2L-9、2L-24、3X-10）.The test shows that there were many strains（Bacillus sp.）capable of cellulose degradation in the dung of giant panda.The giant panda-derived B.axarquienis,B.siamensis were isolated and cultivated for the first time,which enriched the research of giant panda intestinal flora and provided new sources of strains for efficient production of cellulose.Exploring the efficiency of cellulose degradation bacteria in the digestive tract of panda is beneficial for the resource utilization of high fiber feed.