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

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

摘要:

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124h和107h。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1.3g/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67.52mN/m，发酵第29h的发酵上清液表面张力为22.56mN/m。同时，该菌的发酵上清液对石蜡、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。

Abstract:

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 124h and 107h 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 1.3g/L, which was 38% more than that in the fed-batch fermentation system; in the 29th hour of the FCP process, the surface tension of the fermentation supernatant was 22.56mN/m, as a contrast, the surface tension of pure water was 67.52mN/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.