一株海洋柴油降解菌的分离筛选鉴定及其生物表面活性剂特性分析

从中国浙江省舟山渔场油污染的海水和海洋沉积物中分离筛选产生物表面活性剂的柴油降解菌株。经富集培养、形态观察、测定单菌噬油斑、柴油降解率大小初筛到3株柴油降解菌。然后对初筛到的3株菌进行液滴坍塌实验、发酵液的表面张力、排油圈和乳化稳定性的大小测定进一步复筛，最终筛选出1株产生物表面活性剂的柴油降解菌，经18s rRNA鉴定为海洋解脂耶罗威亚酵母（Yarrowia lipolytica）。其柴油降解率为80%，发酵液液体表面张力可从73.4 mN/m降至23.56 mN/m，乳化效率E₂₄为60%。通过薄层色谱、傅里叶变换红外光谱、GC/MS鉴定，其产生的表面活性剂是由C₁₄、C₁₅β-羟基脂肪酸组成的脂肽。

Isolation,screening, and characterization of a diesel degrading darine bacteria and chemical characterization and properties of its biosurfactant

Three strain diesel degrading bacteria could be isolated by a series of conventional screening step including enrichment culture, morphologic observation, hydrolyzing oil spot measurement, diesel oil degradation rate assay etc. Then the fermentation supernatant of first-isolated strains was secondly screened by several screening methods including drop-collapsing method, surface tension method, oil displacement activity and emulsification index. One strain diesel degrading bacteria was isolated with higher surface activity from oil-contaminated seawater and sediments in the Zhoushan fishery, Zhejiang Province, China. This isolated strain was identified as Yarrowia lipolytica based on the analysis of its 18s rRNA sequence. This strain showed strong hydrolyzing oil activity, and the degradation rate of the diesel oil was 80%. The surface tension could be reduced from 73.4 mN/m to 23.56 mN/m, and E₂₄ reach 60%. The results of TLC and IR analysis showed that biosurfactant of the isolated strain was lipopeptide and the results of GC/MS showed that the surfactant was composed of C₁₄、C₁₅β hydroxy fatty acid.