整合型酿酒酵母菌株强化发酵和特性比较

Improvement and Characterization Recombinant Saccharomyces cerevisiae with Integrated Xylose Isomerase for Enhanced Ethanol Production

为了提高木糖异构酶基因在重组酿酒酵母体内的稳定性,并比较不同真菌来源的木糖异构酶在木糖或者葡萄糖-木糖培养基的发酵利用特性,分别构建来自Piromyces sp.E2和Orpinomyces sp.的木糖异构酶基因的整合表达载体,利用同源重组将其整合进入呼吸缺陷型菌株的18S rDNA非转录区,结果测得Orpinomyces的木糖异构酶酶活活力为0.72 U/mg,比Piromyces的木糖异构酶酶活高2.8倍。在木糖培养基中发酵获得乙醇的得率分别为0.40 g/g和0.48 g/g。且整合入Orpinomyces的木糖异构酶基因菌株能获得最高酶活和乙醇得率。

To improve the stability of xylose isomerase （X1） gene in recombinant Saccharomyces cerevisiae and compare with the characteristics of xylose utilization of different gene from different sources, the S. cerevisiae strains, without respiratory-deficiency, were integrated with the XI genes from Piromyces sp. E2 and Orpinomyces sp. individually. The results showed that the ethanol yield of strain harbouring Piromyces sp. E2 or Orpinomyces XI gene was 0.40 or 0.48 g/g of consumed xylosc in media supplemented with 2 % （w/v） xylose. Specific enzyme activity of Orpinomyces XI was 0.72 U/mg that was 2.8-tbld higher than Piromyces Xl＇s. The highest ethanol yield and enzymatic activity were both obtained in the respiratory-deficient strain with integrated Oripinomyces sp. XI gene.