Diversity of halophilic actinomycetes from mud volcano in Xinjiang

Abstract:

[Objective] To know halophilic actinomycetes and their enzyme-producing ability from mud volcano in Usu County, Xinjiang, China. [Methods] Soil samples in mud volcano were isolated with five isolation media containing 5% and 10% NaCl (w/v) with dilution-plate method. The activities of lipase, galactosidase, amylase, esterase and cellulase from isolated strains were qualitatively detected by using five selective media. Base on morphological characteristics, test of salt tolerance, screening of enzymatic characters and sequencing of 16S rDNA gene, strains were selected for phylogenetic analysis. [Results] A total of 43 halophilic actinomycetes and 3 extreme halophilic actinomycetes were obtained. Screening results for enzyme activity showed that 4 halophilic actinomycetes produced lipase, 30 strains produced galac-tosidase, 27 strains produced amylase, 6 strains produced esterase, 4 strains produced cellulose and 1 strain produced 4 enzymes simultaneously. According to 16S rDNA sequence analysis, 24 of 25 detected sequences were affiliated with Nocardiopsis, and the other one was Streptomyces. In the phylogenetic tree, strain 10006 producing 2 enzymes and No-cardiopsis exhalans (AY03600)showed 96.64% similarity (less than 97%), which indicated that strain 10006 was a possi-ble new species. [Conclusion] There are plenty of galactosidase or amylase-producing halophilic actinomycetes and higher enzyme-producing diversity of Nocardiopsis in Usu mud volcano. In addition, there are potential microbial re-sources in this extreme environment.

Key words:mud volcano; Actinomycetes; saline environment