论文部分内容阅读
酵母菌是乙醇发酵工业中非常重要的微生物细胞工厂,发酵过程中温度变化胁迫一直是影响生产效率的重要瓶颈之一,选育具有广泛温度适应性的酵母菌株对提高发酵性能和降低生产成本具有重要意义。通过化学诱变和基于基因组DNA诱变的遗传重组技术对乙醇工业酵母菌的温度适应性进行改造,获得耐热性能和发酵性能得到提高的重组酿酒酵母Saccharomyces cerevisiae T44-2。重组菌株T44-2的最高生长温度比原始菌株CE6提高了3℃,48℃和52℃热激处理1 h,重组菌株的细胞存活率分别是原始菌株的1.84和1.87倍。重组菌株在30℃~40℃范围内具有良好的糖醇转化率和乙醇产量,发酵200 g/L葡萄糖能够产生83.8~91.2 g/L乙醇。重组菌株在43℃和44℃发酵时乙醇产量仍分别有69.2 g/L和52.6 g/L,而此时原始菌株基本没有活性。研究结果为酿酒酵母在乙醇高温发酵中的应用奠定了基础,可极大降低冷却成本。
Saccharomyces cerevisiae is a very important microbial cell factory in the ethanol fermentation industry. Temperature stress during fermentation has been one of the important bottlenecks that affect the production efficiency. Yeast breeding with wide temperature adaptability has the potential to improve the fermentation performance and reduce the production cost Significance. Through the chemical mutagenesis and genetic recombination based on the mutagenesis of genomic DNA, the temperature adaptability of ethanol industrial yeast was modified to obtain Saccharomyces cerevisiae T44-2 recombinant Saccharomyces cerevisiae with improved heat resistance and fermentation performance. The highest growth temperature of recombinant strain T44-2 was 3 ℃ higher than that of the original strain CE6, and 1 h after heat shock treatment at 48 ℃ and 52 ℃. The cell viability of the recombinant strain was 1.84 and 1.87 times higher than that of the original strain respectively. The recombinant strain had good sugar alcohol conversion rate and ethanol yield in the temperature range of 30 ℃ ~ 40 ℃. Fermentation of 200 g / L glucose produced 83.8 ~ 91.2 g / L ethanol. The ethanol yield of the recombinant strain was 69.2 g / L and 52.6 g / L respectively at 43 ℃ and 44 ℃, while the original strain had no activity at all. The results laid the foundation for the application of Saccharomyces cerevisiae in the fermentation of ethanol at high temperature, which can greatly reduce the cooling cost.