Characterization of a novel biosurfactant produced by marine hydrocarbon-degrading bacterium Achromobacter sp. HZ01.

ABSTRACT

AIMS: To purify and characterize the biosurfactants produced by Achromobacter sp. HZ01. METHODS AND RESULTS: After fermentation, one biosurfactant was successfully purified from the fermentation broth of strain HZ01 by centrifugation, extraction using ethyl acetate, silica gel chromatography and reversed phase-high performance liquid chromatography. The critical micelle concentration (CMC) of the biosurfactant and the effects of temperatures, pH and salinities on its stability were determined. Fourier transform infrared spectroscopy, analysis of fatty acids and amino acids and mass spectrometry were used to characterize the biosurfactant. The maximum production yield of the crude biosurfactant reached to 6·84 g l(-1) after incubation for 96 h. Except the favourable adaptability to a wide range of temperatures, pH and salinities, the biosurfactant with a CMC value of 48 mg l(-1) could efficiently emulsify diverse hydrophobic compounds. The chemical formula of this biosurfactant was confirmed to be CH3 -(CH2 )17 -CHO-CH2 -CO-Gly-Gly-Leu-Met-Leu-Leu, in which the oxygen atom of group CHO linked to the last amino acid (Leu), a structure had never been reported before. CONCLUSIONS: The purified biosurfactant is a novel cyclic lipopeptide. SIGNIFICANCE AND IMPACT OF THE STUDY One novel lipopeptide was purified and characterized. The novel biosurfactant exhibited good potential applications, such as bioremediation.