1株脂肪酶产生菌的筛选鉴定及其脂肪酶基因的克隆表达

Isolation,identification of a producing lipase strain and the lipase gene cloning and expression

从武汉市郊蓖麻地土壤中分离到1株产脂肪酶菌株,结合形态观察和生理生化鉴定,扩增16SrDNA并测序,运用Blast比对构建了进化树,发现该菌与粘质沙雷氏菌(Serratia marcescens)的同源性高达99%,初步鉴定该菌属于沙雷氏菌属(Serratia),命名为Serratiasp.HS-L5.克隆了脂肪酶基因HS-Lip5,该基因全长1 842bp,编码氨基酸614个.序列经Blast比对分析发现与Serratia marcescens SM6的lipA序列的同源性高达98%,经氨基酸序列初步分析,发现Serratiasp.HS-L5的氨基酸序列包含脂肪酶共有序列-G-X-S-X-G-.将HS-Lip5基因克隆到表达载体pET-28a,并在E.coli中获得了表达.

A producing lipase strain was isolated from castor-oil plant soil in Wuhan surburb. According to morphological characteristics, physiological biochemical test and se- quence analysis of 16S rDNA, in addition to the phylogenetic tree constructed, the homology between strain HS-L5 and Serratia rnarcescens is up to 99%. Therefore, strain HS-L5 is preliminarily identified as Serratia sp., named Serratia sp. HS-LS. Mean- while, the lipase gene of HS-L5 was cloned and the whole gene sequence is 1 842 bp long, encoding 614 amino acids. The homology compared with lipA of Serratia marces- cens SM6 is close to 98%. The amino acids squences of Serratia sp. HS-L5 contain a li- pase consensus sequence-G-X-S-X-G-. The gene of HS-Lip5 was sub-cloned into expression plasmid pET-28a and expressed in E. coll. Nowadays, there are few reports about Serratia rnarcescens producing lipase isolated from wild environment.