蓝色凝胶平板法筛选生物表面活性剂产生菌

从某炼油厂废水和油泥样中经富集培养、蓝色凝胶平板和发酵液表面张力的测定筛选出生物表面活性剂产生菌8株。选择其中2株BS-03和BS-01作进一步研究。经初步鉴定2株菌均属于假单胞菌属。菌株BS-03和BS-01的发酵液表面张力由56．8mN／m分别降至25．6mN／m和27．4mN／m。电喷雾质谱检测得到菌株BS-03的代谢产物鼠李糖脂主要成分是RhaC10C10，而茵株BS-01则为Rha2C10和Rha2C10C10，其临界胶束浓度CMC值分别为326mg／L和58mg／L。菌株BS-03发酵液对苯、正己烷、正十八烷、柴油和原油的乳化性能都大于70％，而菌株BS-01发酵液则对这些物质的乳化性能不超过60％。

Isolation of Microbe Producing Biosurfactants by Blue Agar Plate

Microorganisms capable of producing biosurfactants are isolated by enrichment culture, blue agar plate and determination of the surface tension of fermentation liquor. Eight strains with high surface activity are isolated from the samples of wastewater and oil sludge (collected from Nanjing Refinery) and two of them (BS-03 and BS-01) are for further study. Through primary identification both strain BS-03 and strain BS-01 belong to Pseudonomas. The biosurfactant produced by strain BS-03 can lower the surface tension of fermentation liquor from 56.8 mN/m to 25.6 mN/m and the extract that yields CMC value of 326 mg/L while that of strain BS-01 is 27.4 mN/m and 58 mg/L separately. Characterization of the products of two strains using electrospray ionizationmass spectrometry reveals that monorhamnolipid (RhaC_10C_10) is predominant in extract of strain BS-03, while dihamnolipids (Rha_2C_10 and Rha_2C_10C_10) are predominant in that of strain BS-01. Emulsification activity of fermentation liquor of strain BS-03 is greater than 70 % using all the hydrocarbons tested, including benzene, hexane, octadecane, diesel and crude oil. But strain BS-01 only emulsifies these hydrocarbons below 60 %.