【摘要】 设计构建了发酵罐体积为5L,单张膜有效面积为0.08m2的平板硅橡胶膜生物反应器封闭循环连续发酵系统,实验研究了该系统在长期运行过程中的发酵反应动力学参数和膜传质动力学参数等基本性能。当发酵罐中乙醇浓度在30～60g·L-1时,得质量浓度为17%～28%的冷凝渗透液。在连续运行中,细胞浓度维持在10～24.8g·L-1,料液罐中葡萄糖浓度大约为30～50g·L-1,乙醇的体积产率为2.33～3.99g·L-1·h-1,膜的渗透通量和分离因子分别为800～1050g·m-2·h-1和5.1～8.6。在连续269h运行中,得到乙醇1999g,基质转化率为87.2%,碳回收率为89.5%,产生的废液量大约为传统间歇发酵过程的22.2%左右。更多还原

【Abstract】 A membrane bioreactor comprised of a fermentor of 5 L and a pervaporation module of 0.08 m2 PDMS membrane was developed for ethanol production by continuous and close circulation fermentation. The kinetic properties of fermentation and membrane performances in the bioreactor were experimentally investigated under long-term continuous operation of the system. A permeate of 17%～28% (wt%) ethanol was extracted while maintaining a level of 30～60 g·L-1 ethanol in the stirred-tank fermentor. The system exhibits good running stability. During continuous operation, cell densities of 10～24.8 g·L-1 and ethanol productivity of 2.33～3.99 g·L-1·h-1 were achieved with utilizing feed streams of 30～50 g·L-1 glucose. Pervaporation flux and selectivity for ethanol were 800～1050 g·m-2·h-1 and 5.1-8.6, respectively. During ferment of 269 hours, the total amount of ethanol produced is 1999 g. Ethanol conversion is 87.2%, and the recovery efficiency of carbon is about 90%. The amount of wastewater released through ferment is roughly equal to two times of ethanol product, which is about 22.2% of that discharged from the conventional ferment technology.更多还原