生物表面活性剂对铜绿假单胞菌摄取烷烃的强化机制

Biosurfactant-enhanced Mechanisms During Uptake of Alkane by Pseudomonas aeruginosa

考察了2株铜绿假单胞菌(Pseudomonasaeruginosa)以正十六烷为底物生长的不同方式,并初步探讨了生物表面活性剂在烃类降解菌摄取烷烃过程中的作用机制.菌株O-2-2在正十六烷中的生长明显快于PS-1,生长过程中O-2-2分泌出鼠李糖脂生物表面活性剂,正十六烷被完全乳化.另外,O-2-2菌细胞表面疏水性高于PS-1,而加入鼠李糖脂使得菌体细胞中脂多糖含量减少,菌细胞表面疏水性明显提高.上述结果表明,鼠李糖脂主要通过乳化疏水性底物和提高降解菌表面疏水性两种机制强化铜绿假单胞菌(P.aeruginosa)对烷烃的摄取.

Two strains of Pseudomonas aeruginosa grown on n-hexadecane and the roles of biosurfactant involved in alkane assimilation by hydrocarbon-degrading bacteria were investigated. P. aeruginosa O-2-2 grew on n-hexadecane much faster than P. aeruginosa PS-1. During the growth on n-hexadecane,O-2-2 produced an extracellular rhamnolipid biosurfactant and nhexadecane was emulsified completely. In addition,O-2-2 exhibited higher cell surface hydrophobicity than PS-1. The presence of rhamnolipid biosurfactant caused a significant reduction of lipopolysaccharide in cell outer membrane, resulting in cell surface hydrophobicity increase. These findings indicated that emulsification of hydrophobic substrate and enhancement of cell surface hydrophobicity were two possible mechanisms, by which rhamnolipid could enhance alkane assimilation.