Cloning and sequence analysis of lipase gene of halophilic bacteria isolated from mud crater of Bledug Kuwu, Central Java, Indonesia

Abstract

Five lipase genes (lipab4, lipab8, lipab15, lipag18, and lipab18) have been isolated from Halomonas and Chromohalobacter local strains of Bledug Kuwu isolates. Based on amino acid sequence analysis, the genes showed some unique motif of amino acid sequences. All of lipases were classified as a member of family IV (HSL=hormonesensitive lipase). These lipases show high similarities of conserved regions with lipolytic of Halomonas and formed a distinct cluster with other types of HSL, such as esterase/lipase and carboxylesterase. All of lipases contain more negative charged of amino acid residues compared to the mesophilic and thermophilic ones, and tend to have similarity to lipases of moderate halophilics. The result of homology and phylogenetic analysis showed that these lipases were clustered into three groups. Group I (lipab8, lipab18 and lipag18) closed to lipolytic gene of Halomonas elongata DSM 2581, while groups II (lipab4) and III (lipab15) created new branches in the phylogenetic tree. In addition, analysis of GC, GC-AT and GC-AT content on the codon usage of the genes revealed the unique profile compared to that the other lipase genes.