白蚁肠道纤维素降解菌的分离和鉴定

Isolation and Identification of Cellulose-degrading Bacteria in Termite Gut

研究白蚁肠道产纤维素酶菌株,寻找新的高产纤维素酶菌株。采用培养基分离方法,纯化白蚁肠道产纤维素酶菌株,比较菌株3种纤维素酶活性,并进行16S rDNA及生化鉴定。筛选出10株产纤维素酶菌株(CX1~10),其中CX10菌株水解圈直径比值最大为2.78。测得48 h内CX10菌株滤纸酶(FPA)活力最高,为49.5 IU·mL^-1。CX9的纤维素外切酶(CX)活力最高,为25.9 U·mL^-1。CX8、CX9和CX10的纤维素内切酶(CMCase)活力分别为67.8、70.4和95.0 IU·mL^-1。经鉴定白蚁肠道产纤维素酶菌株为芽胞杆菌属(Bacillus)、枸橼酸杆菌属(Citrobacter)及沙雷菌属(Serratia)。本研究从低等白蚁肠道成功分离出10株菌,其中CX10纤维素综合酶活力最高,为坚强芽胞杆菌(Bacillus firms)。

In order to seek high cellulase-producing strains, the termites intestinal flora was studied. The bacteria in intestinal tract were isolated by the method of medium separation under aerobic and anaerobic conditions. Three cellulase activities in the screened strains were analyzed at 48 h, and the strains were identified by gene sequencing and biochemical analysis. Ten cellulase-producing bacteria strains were screened(CX1-10), and the ratio of the diameter of hydrolysis zone was the largest(2.78) in CX10. Filter Paper Enzyme(FPA) in CX10 had the highest activity, reaching 49.5 IU·mL^-1. Cellulose Endonuclease in CX9 had the highest activity, reaching 25.9 IU·mL^-1. Cellulose endoglucanases in CX8, CX9 and CX10 were 67.8, 70.4 and 95.0 IU·mL^-1, respectively. All of the screened strains were identified as Bacillus, Citrobacter and Serratia. In this study, 10 bacteria were successfully isolated from the intestines of lower termites, among which the CX10 synthesize cellulase activity was the highest, which was identified as Bacillus firms.