在GPD1中整合表达bglⅡ基因改善酒精发酵

Improvement of Ethanol Fermentation by Expression of Trichoderma reesei bglⅡ Gene and Disruption of GPD1 in Saccharomyces cerevisiae

依据同源重组的原理将来源于里氏木霉的β-葡萄糖苷酶基因bglⅡ整合到工业酿酒酵母染色体上的3-磷酸甘油脱氢酶基因GPD1中,通过G418抗性筛选得到重组子。实验数据表明,重组子Saccharomyces cerevisiaeCG1利用纤维二糖的能力显著提高,产甘油能力下降。引入外源基因后酵母性状与亲代相比没有显著差异,但生长时具自絮凝能力。当S·cerevisiaeCG1以玉米粉为原料进行浓醪酒精发酵,与亲代工业酿酒酵母比较,发酵液乙醇浓度得到提高,甘油含量降低,纤维二糖含量显著减少。

Based on homologous recombination, β-glucosidase gene bgl Ⅱ from T. reesei was integrated to the chromosomal DNA of industrial Saccharomyces cerevisiae and the key enzyme gene coding glycerol-3-phosphate dehydrogenase （ GPD1 ） of the glycerol anabolic pathway was disrupted contemporaneously, and recombinats were screened through increasing G418 concentration. It was shown that cellobiose utility capability of recombinant S. cerevisiae CG1 was increased evidently, glycerol productivity was decreased, and the bgl Ⅱ gene was expressed stabilized in the host cell. No impact on the cell character was appeared after introduced extrinsic gene, but the cells were flocculate when growing. When compared with parent industrial S. cerevisiae Y in very high gravity （VHG） ethanol fermentation from cem powder, ethanol productivity was increased, glycerol productivity was decreased, and the cellobiose in the broth was decreased obviously detected by HPLC analysis.