不动杆菌生物乳化剂活性成分研究

Components in Bioemulsifier Produced by Acinetobacter Strains

通过乳化活性分析、化学成分分析和相关基因的分析,对3株海洋来源的不动杆菌分离株和2种不动杆菌模式菌的生物乳化剂产生能力和活性成分进行了分析,结果表明,这些菌都能产生生物乳化剂.通过PCR检测,其中只有深海菌株wp02421编码与乳化剂Emulsan产生密切相关的酯酶基因.气质联用仪证明该菌所产的乳化剂含有脂肪酸组分,主要是正十六烷酸和正十八烷酸,表明菌株wp02421产生的乳化剂与Emulsan类似,糖脂是主要活性成分之一.此外,通过PCR检测,证明了5株不动杆菌全部编码外膜蛋白A基因(ompA).它们的氨基酸序列与Acinetobacter radioresistens KA53的乳化剂Alasan中的主要活性蛋白AlnA的同源性为71.26%～80.23%.以上结果表明,5株菌的生物乳化剂中都可能含有AlnA的乳化蛋白,而菌株wp02421同时还产类似Emulsan的糖脂.

Bioemulsifiers of 5 Acinetobacter strains including 3 marine and two type strains, were examined in respects of emulsifying activity, component analysis and gene detection. Results showed that all the bacteria could produce bioemulsifiers. However, only the isolate wp02421 from deep sea sediment was positively detected with PCR of the gene encoding esterase, which plays an important role in emulsan production. Gas chromatography and mass spectrometry （GC-MS） analyses revealed that hexadecane and octacecanoic acids were the main components of fatty acids as the bioemulsifier was produced by isolate wp02421, indicating that the glycolipid in the emulsan was also produced by isolate wp02421. In addition, the outer membrane protein A gene, ompA, was detected in all the 5 strains by PCR. The proteins encoded by these genes showed 71.26% to 80.23% homologies with the well studied OmpA （named AlnA） of Acinetobacter radioresistens KA53. This suggests that OmpA might be the active component of the bioemulsifiers in all the strains. Thus, in the case of wp02421, both glycolipid and OmpA probably participated in emulsification. Fig 3, Tab 2, Ref 15