细胞对硅橡胶复合膜渗透蒸发分离性能的影响

利用自制的硅橡胶复合膜对乙醇-水模型溶液、含有干酵母的乙醇-水模型溶液、以及实际发酵液进行渗透蒸发分离乙醇实验，研究了细胞对膜性能的影响、结果表明：与纯乙醇模型溶液的分离相比，膜对含有干酵母的乙醇-水模型溶液、真实发酵液的分离表现出更好的性能，显示细胞的存在和活动对膜传质有一定的促进作用．连续发酵过程中，在一定的细胞浓度下（10g／L），硅橡胶膜维持了长期稳定的分离性能；产品乙醇的有效分离降低了其对酵母细胞的抑制作用，使沉积在膜面上的细胞层促进了膜的分离性能；但提高细胞浓度（15g／L）后却因更厚的细胞层的堆积造成膜面传递状况劣化，使膜性能下降．因此发酵液中的细胞浓度、膜面上的细胞沉积以及膜性能之间存在一种最佳的相互促进和搭配关系．

Effect of biomass on the pervaporation performance of composite silicone rubber membrane

The effects of yeast biomass on the pervaporation performance of composite silicone rubber membrane were studied by using model ethanol solution with or without dry yeast biomass and the real fermentation broth. Compared with the model ethanol solution without yeast cells, the solution with dry yeast cell and the real fermentation broth containing active cells gave higher pervaporation performance, which shows that the presence of biomass caused the increase of the rates of mass transfer through the membrane. During the continuous fermentation with the cell concentration of 10 g/L, the effective removal of inhibitory product by the membrane resulted in a long-term stable separation performance, the cells deposited on the membrane surface enhanced the selective mass transport behaviors through the membrane. However, it was observed that more enriched biomass concentration in broth, e.g. , 15 g/L, caused a quick decrease in membrane performance. This result indicates that there is an optimal- match relationship among the cell concentration in broth, the cell film on the membrane surface and the membrane performance.