固定化酵母重复发酵性能调控

以2.5%海藻酸钠(w/v)、2%氯化钙(w/v)、2%菌体添加量(w/v,细胞干重)包埋固定酿酒酵母,通过增殖活化和批次短周期发酵对固定化粒子的发酵性能进行调控,减缓循环发酵中固定化粒子发酵性能的退化,同时利用扫描电镜(SEM)对固定化粒子的结构和酵母细胞分布情况进行表征.结果表明:调控后,固定化粒子在葡萄糖浓度为80g/L,pH 4.0,35℃的条件下发酵,发酵性能得到明显改善.调控前,连续3批次发酵,平均乙醇生产强度为0.33g/(L·h);调控后,批次发酵周期由72h缩短为24h,连续5批次发酵,平均乙醇生产强度提高至1.22g/(L·h).

Performance of repeated fermentation using recycled immobilized yeast

Saccharomyces cerevisiae was embedded by 2.5% (w/v) sodium alginate and 2% (w/v) calcium chloride at the yeast concentration of 2% (w/v, dry cells). The immobilized yeast was employed to produce ethanol continuously in repeated batch fermentation system. In order to slow down the performance degradation of immobilized yeast cells, regulation of their fermentation capability was conducted through Yeast Extract Peptone Dextrose (YEPD) medium activated. Additionally, the structure of immobilized particles and the distribution of yeast cells were characterized by Scanning Electron Microscope (SEM). The immobilized beads fermentation performance was significant improved after regulated. The experiment was carried out with the condition of pH 4.0, 35℃ when the glucose concentration was 80g/L. the experiment results showed: before regulated, the mean value of ethanol volumetric productivity was 0.33g/(L·h) in three sequential fermentation cycles; after regulated, the fermentation time of each batch was shorted from 72h to 24h, the mean value of ethanol volumetric productivity was 1.22g/(L·h) in five sequential fermentation cycles.