云斑白条天牛幼虫肠道纤维素降解菌的分离鉴定及产酶条件的优化

Isolation and identification of cellulolytic bacteria and optimization of enzymatic production conditions in the intestinal tract of the larva of Batocera lineaolata(Chaevroat)

为筛选云斑白条天牛[Batocera lineaolata(Chaevroat)]幼虫肠道中高效纤维素降解菌,实现纤维素的高效利用,以羧甲基纤维素钠为唯一碳源,并利用刚果红平板染色法初筛、纤维素酶活测定复筛,从云斑白条天牛幼虫肠道中分离产纤维素酶菌株;采用形态学观察和16S rDNA基因序列同源性分析方法对该菌株进行鉴定,单因素试验法对菌株的产酶条件进行优化。结果表明:从45株纤维素降解菌中通过刚果红染色获得2株高效产纤维素酶菌株A04、A07,鉴定分别为苍白杆菌属(Ochrobactrum)A04、拉乌尔菌属(Raoultella)A07。初步确定苍白杆菌属A04在温度32℃、初始pH=6、以酵母膏为氮源条件下滤纸酶(FPase)活力最大;拉乌尔菌属A07产纤维素酶在温度32℃、初始pH=7、以酒石酸铵为氮源条件下FPase活力最大。

To identify high-efficient cellulose degrading bacteria from the intestinal tract of the larva of Batocera lineaolata(Chaevroat)and promote the efficient utilization of cellulose,high-yielding cellulase strains were isolated from the intestinal tract firstly by the methods of Congo red staining method and then by cellulase activity analysis.The strains were identified by morphological observation,physiological and biochemical characteristics and homology analysis of 16 S rDNA gene sequence.The enzyme production of the strain was optimized by single factor test.The results showed that two efficient cellulase-producing strains A04 and A07 were obtained from 45 cellulose degrading bacteria by Congo red staining,and were identified as Ochrobactrum A04 and Raoultella A07.It was preliminarily determined that when the temperature was 32℃,initial pH=6 and yeast extract was used as the nitrogen source,the activity of Ochrobactrum A04 of FPase was the maximum.The optimum conditions for cellulase production of Raoultella A07 were 32℃,initial pH=7,and sodium sulphate used as nitrogen source.