Gene Cloning and Expression of a Cold-adapted Lipase from Brachybacterium sp. DB5 Isolated from Glacier Soil

LIU Wan-li1,2,ZHANG Guo-hua2,CHEN Qiang1,YANG Pei-long2,ZHANG Yu-hong2,3,YAO Bin2(1.Institute of Biochemistry and Molecular Biology,School of Life Science,Lanzhou University,Lanzhou 730000;2.Key Laboratory of Feed Biotechnology,Ministry of Agriculture,Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081;3.Biotechnology Research Institute,CAAS,Beijing 100081,China)

glacier soil;Brachybacterium;cold-adapted lipase;gene expression

Eleven lipase-producing bacterial strains were screened from 54 cold-adapted strains,which were isolated from No.1 Glacier soil of Xinjiang.Among them,one strain identified as Brachybacteriumsp.DB5 according to 16S rDNA sequence analysis,showed the highest lipolytic activity.The lipase gene LipDB5with 933 bp was cloned from Brachybacteriumsp.DB5 using TAIL-PCR technology.LipDB5encoded 310 amino acid and one stop codon with a theoretical molecular weight of 34.8 kDa,but without signal peptide.The lipase gene was functionally expressed in E.coliBL21(DE3).The recombinant LipDB5 was most active at 30 ℃,kept 34.7% of activity at 5 ℃.Moreover,the recombinant enzyme retained 17.4% of the activity after incubation at 60℃ for 30 min.These activity data indicated that LipDB5 had some cold-adapted lipase characteristics.As a new cold-adapted lipase,LipDB5 has the potential application value in the field of bio-catalysis.