菌株Pseudomonas aeruginosa BC1发酵-渗透汽化耦合制备鼠李糖脂

Rhamnolipids Production by Pseudomonas aeruginosa BC1 via Fermentation Coupling with Pervaporation System

采用发酵-渗透汽化耦合(fermentation coupling with pervaporation,FCP)系统和分批补料式发酵系统培养Pseudomonas aeruginosa BC1制备生物表面活性剂鼠李糖脂,两轮发酵过程分别持续124 h和107 h。在FCP系统中,最大细胞吸光度OD600为1.06;生物表面活性剂OD600为0.61;鼠李糖脂最终产量为1.3 g/L,相比于分批补料式发酵系统提高38%;对比纯水的表面张力67.52 m N/m,发酵第29 h的发酵上清液表面张力为22.56 m N/m。同时,该菌的发酵上清液对液体石蜡、机油、柴油、正己烷、十六烷均有较好的乳化能力。经GC-MS结合SPME分析发现,FCP系统分离出的渗透蒸汽冷凝液中含有乙醇、戊醇等有机物。实验结果表明,相比分批补料式发酵系统,FCP系统能够分离发酵过程中产生的一部分挥发性代谢产物,减轻这些物质对细胞生长的抑制,使细胞浓度和鼠李糖脂产量都有明显提高。

Strain Pseudomonas aeruginosa BC1 was cultured in the fermentation coupling with pervaporation（ FCP） system and the fed-batch fermentation system separately for production of rhamnolipids and the two fermentation process each lasted for 124 h and 107 h respectively. In the FCP system,the maximum optical density OD600 of the biomass was 1. 06; maximum optical density OD600 of biosurfactant was 0. 61; meanwhile,the total rhamnolipids concentration was quantified as 1. 3 g / L,which was 38% more than that in the fed-batch fermentation system; in the 29 th hour of the FCP process,the surface tension of the fermentation supernatant was 22. 56 m N / m,as a contrast,the surface tension of pure water was 67. 52 m N / m. Furthermore,the fermentation supernatant showed excellent emulsifying ability to liquid paraffin,motor oil,diesel oil,n-hexane and hexadecane. The permeation vapor was analyzed by gas chromatography mass spectrometry（ GC-MS） coupling with solid-phase micro-extraction（ SPME） and several volatile organic compounds were detected,including ethanol,pentanol etc. The data indicate that,in contrast to the fed-batch system,the FCP system can increase the cell concentration and the rhamnolipids production through removing growth inhibition of cells from some volatile metabolites produced in the fermentation process.