硅橡胶膜生物反应器中乙醇发酵与渗透汽化的耦合

用硅橡胶膜生物反应器(SMBR)实验研究连续发酵-渗透汽化的耦合性能。发酵微生物采用酿酒干酵母,所用碳源为工业级葡萄糖。发酵过程由于产物抑制作用,在乙醇质量浓度达到73 g/L时趋于停滞,而耦合渗透汽化膜后,发酵罐内的乙醇质量浓度降低并维持在40 g/L,使发酵可以连续稳定地进行。在SMBR运行达到稳态后,乙醇的体积产率为4.02 g/(L.h)。发酵液中乙醇质量浓度维持在20~63 g/L,聚二甲基硅氧烷(PDMS)膜的总渗透通量为1 220~800 g/(m2.h),分离因子为5~9.2。与传统发酵和分离相同进料质量分数的乙醇溶液相比,乙醇发酵和渗透汽化在硅橡胶膜生物反应器中能相互耦合并得到强化。与较小规模耦合系统(发酵体积1 L和2 L)比较,性能稳定良好。

Performances of Ethanol Fermentation and Pervaporation in a Silicone Rubber Membrane Bioreactor

Performance of fermentation and pervaporation in a coupling silicon rubber membrane bioreactor(SMBR) was experimentally studied.The microorganism was alcohol instant active dry yeast and the carbon source substrate was glucose of technical grade.Because of product inhibition,fermentation tended to suspend when accumulated ethanol concentration in the fermentor climbed to 68 g/L.With coupling of pervaporation,ethanol concentration decreased quickly to a constant value of 40 g/L at which fermentation could proceed continuously.Ethanol productivity of 4.02 g/(L·h) was achieved after SMBR reached a steady state.When ethanol concentration in fermentation broth was maintained at 20~63 g/L,total flux and selectivity resulted from the PDMS membrane were(1 220)~800 g/(m~2·h) and 5~9.2 respectively.Compared with the traditional fermentation and model solution under similar experimental conditions,fermentation and pervaporation could be well coupled and enhanced each other in the silicon rubber membrane bioreactor.Performances were steady and better in bulkier system compared with that valued in smaller one.