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Screening of an efficient biosurfactant-producing bacterial strain and the structure and property of its surface-active metabolic product.

XIAO Bing1,2, YANG De-yu1,2, SHI Rong-jiu2**, ZHANG Ying2, ZHANG Yang1, HAO Jin-sheng3, LI Guo-qiao3, ZHAO Jin-yi3   

  1. (1College of Chemistry and Life Sciences, Shenyang Normal University, Shenyang 110034, China; 2Key Laboratory of Terrestrial Ecological Processes, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; 3Center Laboratory of No. 2 Oil Production Plant, Daqing Oilfield Company Ltd., Daqing 163414, Heilongjiang, China)
  • Online:2013-03-10 Published:2013-03-10

Abstract: By adopting blood-agar procedure combined with surface tension screening strategy, an efficient surfactant-producing bacterial strain DY-9 was successfully isolated from the produced water from low-permeability Gaotaizi oil reservoir, Daqing Oilfield of Northeast China. The comparison with the homoeologous 16S rDNA sequences deposited in the GenBank showed that the DY9 had a 99% sequence similarity with Bacillus licheniformis. When cultured on a medium with 20 g·L-1 of molasses as the sole carbon source at 180 r·min-1 and 45 °C, the DY-9 could grow well, and decrease the surface tension of culture broth from initial 69.3 mN·m-1 to 26.5 mN·m-1 within 24 h. After cultured for 48 h, the maximum raw biosurfactant yield of the strain reached 0.48 g·L-1, and the critical micelle concentration was 28 mg·L-1. The biosurfactant produced by the DY9 could keep stable under the conditions of high temperature (120 °C) for 1 h, high salinity (12% NaCl), and wide pH (2-12), and the surface tension of the zymotic fluid within 48h was lower than 30 mN·m-1. The analysis with infrared spectroscopy (IF-TR) and high-pressure liquid chromatographymass spectrometry (HPLC-MS) revealed that the surface-active product of the DY-9 was a cyclic structure lipopeptide biosurfactant.

Key words: tobacco, latently fragrant substance, stability, genotype and environment interaction, AMMI model.