SCREENING AND CHARACTERIZATION OF LIPASE FROM HUANGSHUI RIVER IN CHINA

281 lipase-producing bacterium strains were high throughput screened from 1440 strains, these strains isolated from the mud of HuangShui River（Xining section）. Based on morphological characterics and 16S rDNA sequence homology, 281 strains were identified. Four lipolytic strains Pseudomonas sp. D1, Pseudomonas putida D2, Pseudomonas baetica D3,and Pseudomonas peli D4 were selected as there predicted lipase possess 1.3-positional specificity. Three lipase genes PPL1、PPU2、PFR3 were cloned and expressed in Escherichia coli BL21 (DE3) respectively. The molecular masses of the lipase were estimated to be 49.7 kDa, 73.6 kDa and 34.9 kDa in SDS-PAGE, respectively. One lipase chaperone gene PME4 were cloned and expressed in E.coli too. The PME4 gene is 1137bp long, encoding a 41.7 KDa recombinant protein. We achieved for the purification of the recombinant lipase using nickel affinity chromatography. We use these system to test the molecular chaperone hypothesis by investigating whether PME4 could activate prelipase or other unknown functions.