铜绿假单胞菌对长链烷烃的摄取模式

研究了一株铜绿假单胞菌(CGMCC 1.1785)摄取长链烷烃的模式。铜绿假单胞菌1．1785能够以固态的长链烷烃为唯一碳源生长，在培养过程中产生表面活性代谢物。烃与水相的界面面积是细菌生长重要的影响因素，说明传质限制的存在。由于该菌不能够利用鼠李糖脂增溶的烃作为碳源，因此添加鼠李糖脂能够强化烃摄取的主要原因是烃界面的扩大。细胞表面疏水性从开始的急剧升高到后来的不断下降，说明在不同生长阶段细胞对烃的摄取模式是不同的。由此认为，铜绿假单胞菌1.1785既没有通过表面活性剂介导模式获取烃，也并非完全通过直接接触模式获取烃。据此提出该菌采用了一种运动接触的烃摄取模式，其趋化运动能力在这种摄取过程中起到重要作用。

Mode of Long-chain Alkane Uptake by a Pseudomonas aeruginosa

The mode of long-chain alkane uptake by Pseudomonas aeruginosa (CGMCC 1.1785) was studied. P. aeruginosa 1.1785 is capable of using solid long-chain alkane as sole carbon source and producing surface active compound as metabolite. The mass transfer limitation in uptake of alkane was confirmed from the observation that interfacial area of eicosane with water dominates the growth rate of this strain. The enhancement of eicosane uptake by rhamnolipid was mainly caused by increase of interfacial area, since the pseudosolubilized alkane can not support the growth of P. aeruginosa 1.1785. Cell surface hydrophobicity was increased dramatically at the initial phase of growth and followed by a gradual decrease, which indicates that different modes are employed by P. aeruginosa 1.1785 at different growth phase. Therefore, the surfactant mediated mode can be negligible in the uptake process, while the directly attachment mode may not work throughout the growth of P. aeruginosa 1.1785. We proposed a novel uptake mode, in which the chemotaxis of this strain plays an important role.