Characterization of an alkaliphilic biosurfactant- producing strain of Dietzia
一株产脂肽类表面活性剂的碱性Dietzia菌及特性研究

Objective] Isolating and characterizing biosurfactant-producing bacteria. Methods] Biosurfactant-producing bacteria were isolated by enrichment method. The morphological, biochemical and physiological characteristics and 16S rRNA gene sequence were determined to identify the taxonomic position of strain 3372. The optimal conditions for the growth and biosurfactant production of strain 3372 were investigated. Results] Strain 3372 was isolated from marine water sample. It grows from pH 7.0 to 11.0 (optimum at pH 9.0), from 10 °C to 45 °C (optimum at 30 °C) and up to 12 % salinity. 16S rRNA gene sequence analysis showed that the strain belonged to the genus Dietzia and most closely related to Dietzia cercidiphylli. Strain 3372 was able to grow and reduce the surface tension of culture broth to 32.95 mN/m when cultured using paraffin as sole carbon source at pH 9.0 and 3% salinity. The biosurfactants produced by strain 3372 was identified as lipopeptides by thin layer chromatography. Conclusion] Strain 3372 was a new alkaliphilic member of lipopeptides-producing bacteria, which has potential application in the processes where high pH is common.