Abstract: A strain of Bacillus sp. was isolated from the oil-water mixture samples of oil field. The fermentation supernatant revealed high surface activity, and the biosurfactant showed high stability against heat, pH and salinity. The optimum conditions of biosurfactant-producing were determined as follows: 30 g/L maltose as carbon substrate, 1.5 g/L mixture of (NH4)SO4+NaNO3 (1:2, volumetric ratio) as nitrogen substrate, temperature 37℃, 100 mL medium in 500 mL total vessel volume, pH 7.0 and 10%(j) inoculums. The biosurfactant was obtained by acid precipitation and chemical extraction method. IR analysis showed that the biosurfactant contained peptide bond and fatty acid bond, which indicated that the biosurfactant was lipopeptide.

Key words: biosurfactant, Bacillus sp., fermentation conditions

摘要： 从大庆油田油水混合样中分离得到一株芽孢杆菌(Bacillus sp. W112). 菌株发酵液具有较高的表面活性，而且其表面活性剂具有较好的温度、pH和盐稳定性. 对表面活性剂产生条件进行优化，确定了最佳碳源为30 g/L麦芽糖，最佳氮源为1.5 g/L的混合氮源[硫酸铵+硝酸钠(1:2, j)]，培养温度为37℃，在500 mL三角瓶中的装液量为100 mL，pH值为7.0，接种量为10%(j). 通过盐酸沉淀-化学试剂萃取法提取得到浅黄色固体产物，通过红外光谱分析，初步确定为一种脂肽类表面活性剂.

关键词: 生物表面活性剂, 芽孢杆菌, 发酵条件