Zhang Yuanyuan, Wang Caiyun, Wang Lulu, Yang Ruoxin, Hou Peilei, Liu Junhong
Department of Pharmaceutics, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao, 266042, Shandong, China.
J Ind Microbiol Biotechnol. 2017 Mar;44(3):453-464. doi: 10.1007/s10295-016-1893-9. Epub 2017 Jan 18.
To achieve a cost-effective bioconversion of lignocellulosic materials, a novel xylose/glucose co-fermentation process by co-culture of cellulose-utilizing recombinant Saccharomyces cerevisiae (S. cerevisiae) and xylan-utilizing recombinant Pichia pastoris (P. pastoris) was developed, in which ethanol was produced directly from wheat straw without additional hydrolytic enzymes. Recombinant S. cerevisiae coexpressing three types of cellulase and recombinant P. pastoris coexpressing two types of xylanase were constructed, respectively. All cellulases and xylanases were successfully expressed and similar extracellular activity was demonstrated. The maximum ethanol concentration of 32.6 g L with the yield 0.42 g g was achieved from wheat straw corresponding to 100 g L of total sugar after 80 h co-fermentation, which corresponds to 82.6% of the theoretical yield. These results demonstrate that the direct and efficient ethanol production from lignocellulosic materials is accomplished by simultaneous saccharification (cellulose and hemicellulose) and co-fermentation (glucose and xylose) with the co-culture of the two recombinant yeasts.
为实现木质纤维素材料的经济高效生物转化，开发了一种通过纤维素利用重组酿酒酵母（Saccharomyces cerevisiae）和木聚糖利用重组毕赤酵母（Pichia pastoris）共培养进行木糖/葡萄糖共发酵的新工艺，该工艺可直接从小麦秸秆生产乙醇，无需额外的水解酶。分别构建了共表达三种纤维素酶的重组酿酒酵母和共表达两种木聚糖酶的重组毕赤酵母。所有纤维素酶和木聚糖酶均成功表达，并表现出相似的胞外活性。80小时共发酵后，从小麦秸秆中获得的最大乙醇浓度为32.6 g/L，产量为0.42 g/g，对应于100 g/L的总糖，这相当于理论产量的82.6%。这些结果表明，通过两种重组酵母的共培养同时进行糖化（纤维素和半纤维素）和共发酵（葡萄糖和木糖），可实现从木质纤维素材料直接高效生产乙醇。
