Bacterial diversity of lipase-producing strains in different soils in southwest of China and characteristics of lipase

Abstract

Due to the rapid development observed in industries, environmental pollution became more and more critical. Lipase-producing strains played a key role in the enzymological remediation of polluted soils. Diversity of culturable lipase-producing bacteria in the southwest of China was studied with 198 samples collected from different points, along the transect from Tibetan Plateau-Ya An–Sichuan Basin. The enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) technology was used to amplify the isolated lipolytic producer’s DNA samples and the amplified results were analyzed by NTSYS-pc2.1 to identify the similarity of isolates. A total of 54 bacterial strains were isolated from samples: 21 strains from Sichuan Basin (38.9%), 15 strains from Ya An (27.8%) and 18 strains from Tibetan Plateau (33.3%). The result of enzyme activity analysis showed that intracellular enzyme activity was nearly three folds than extracellular enzyme activity, and the intracellular enzyme activity was 6.79, 6.23 and 5.59 U/ml from Sichuan Basin, Ya An and Tibetan Plateau, respectively. Based on 16S rRNA gene sequence analysis, 12 strains were identified and belonged to Bacillus, Klebsiella, Pseudomonas and Enterobacter. The results showed that the Bacillus strains were the preponderant strains in the Tibetan Plateau and the Klebsiella strains were predominant isolates in Ya An. It suggested that the strains of Klebsiella were the transitional lipase-producing strains from Tibetan Plateau to Sichuan Basin. It could be concluded that the diversity of lipase-producing strains showed a transitional tendency: diversity of lipase-producing strains in Sichuan Basin were significantly higher than that of other two places and the diversity decreased gradually from plain region to Plateau region. Key words: Enterobacterial repetitive intergenic consensus-polymerase chain reaction(ERIC-PCR), lipase-producing microorganisms, diversity, Tibetan Plateau