壳聚糖/海藻酸盐微胶囊固定化酿酒酵母生产乙醇

The Cultivation of Immobilized Saccharomyces cerevisiae by Chitosan/alginate Microcapsules and Production of Ethanol

针对酿酒酵母细胞发酵生产乙醇存在的产物抑制,细胞利用率低,发酵效率低等主要问题,以壳聚糖、海藻酸钠为微载体制备材料,采用脉冲电场液滴工艺制备载细胞壳聚糖/海藻酸盐微胶囊,以细胞生长量和乙醇产量为检测指标,对微囊化酿酒酵母生长代谢特性进行研究。结果表明,微囊化酿酒酵母呈现"S"型生长,生长代谢规律与游离培养相似;经过批次培养,最大细胞生物量2.9×108个/mL显著高于游离培养样品1.9×108个/mL,乙醇产量12.6g/L高于游离培养工艺产量10.2g/L。正交设计试验表明,壳聚糖分子量是影响微囊化细胞乙醇产量的显著因素,优化条件组合为壳聚糖分子量5万、壳聚糖浓度2.0mg/mL、成膜反应时间15min及培养基pH6.0,在此条件下获得乙醇产量为13.5g/L。

In present, there are many problems in the Saccharomyces cerevisiae fermentation industry, such as product inhibition, low cell utilization, and low productivity. In order to solve these problems, the Saccharomyces cerevisiae cell-loaded chitosan/alginate microcapsules were prepared by the mild and efficient impulsive electrostatic preparation process. The culture properties of microencapsulated Saccharomyces cerevisiae were studied. Experimental results showed that ceils can grow normally in the microcapsule, the growth and metabolism rules between microencapsulated culture and free culture were similar. By batch culture, cell biomass reached 2.9 × 10^8/mL and ethanol output reached 12.6 g/L, which were higher than free culture （ cell biomass 1.9 × 10^8/mL, ethanol output 10.2 g/L）. The effect of microencapsulation technology on ethanol output of Saccharomyces cerevisiae were studied. The orthogonal experimental results showed that the significant factor was molecular weight of chitosan. Under the condition that the molecular weight of chitosan 50 000, concentration of chitosan 2.0 mg/mL, membrane formation time 15min, the culture medium pH value 6.0, the ethanol output can reach 13.5g/L, which was higher than the one under other conditions .