Abstract: This experiment studied a biosurfactantproducing bacterial strain isolated from seawater, designated as dhs-330. Phylogenetic analysis of the homoeologous 16S rDNA gene sequences, the optimization of culture conditions of carbon source, nitrogen source, pH and temperature, MALDITOF Mass Spectrometry identification of the products, and antimicrobial activity assay were carried out. The 16S rDNA sequence of Bacillus sp. dhs330 shared a 99% sequence similarity with Bacillus mojavensis. Bacillus sp. dhs-330 decreased the surface tension of culture medium from 70 mN·m^-1 to 27 mN·m^-1. It could grow well with high production of biosurfactants under the following conditions: glycerol as carbon source, yeast extract as organic nitrogen source, urea as inorganic nitrogen source, initial pH 6.5-7.0 and 30-35 ℃. Its principal products were blendbiosurfactants of lipopeptide and glycolipid, which showed antimicrobial activity against marine fouling bacteria Bacillus pumilus dhs04. Strain dhs330 presented a potential application in blend-biosurfactant production and anti-fouling technology.

Key words: Chongqing City, winter wheat, APSIM model, calibration, validation.