重组酵母发酵半纤维素水解液生产酒精的研究  

Ethanol Production from Hemicellulosic Hydrolysate by a Recombinant Yeast

作　　者：赵晶[1] 夏黎明[1] 

机构地区：[1]浙江大学化学工程与生物工程学系,浙江杭州310027

出　　处：《高校化学工程学报》2010年第2期247-251,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：国家"863"高技术研究发展计划资助项目(2007AA05Z401);国家科技支撑项目(2007BAD66B02);浙江省自然科学基金重大资助项目(Z407010)

摘　　要：玉米秸秆中的半纤维素主要由五碳糖组成,普通的酿酒酵母不能发酵五碳糖。今利用基因重组酵母Sacchromyces cerevisiae ZU-10发酵玉米秸秆半纤维素水解液生产酒精,针对半纤维素水解液中的主要发酵抑制物,研究了硫酸根离子、乙酸、糠醛对重组酵母生长的影响,发现S.cerevisiae ZU-10细胞对SO42·,乙酸和糠醛的耐受浓度分别为5g·L·1、0.25g·L·1和0.08g·L·1。对玉米秸秆半纤维素的水解工艺进行了比较研究,结果表明,玉米秸秆采用1%H2SO4(固液比1:10),在95℃水解12h,其中的半纤维素水解率达到93%,发酵抑制物相对较少。半纤维素水解液经石灰中和、真空浓缩及离子交换处理后,可用于酒精发酵。半纤维素水解液的糖浓度与浓缩倍数及发酵抑制物浓度成正相关,对于重组酵母S.cerevisiae ZU-10,半纤维素水解液的适宜糖浓度为80g·L·1。在此浓度下,接种量1.2g·L·1(细胞干重计)、30℃、厌氧发酵96h,酒精浓度为31.05g·L·1,水解液中的木糖利用率达到95.85%。该研究结果对于促进半纤维素资源的转化利用,加速秸秆酒精的产业化进程具有重要意义。Hemicellulose in corn stover contains mostly pentose （primarily xylose）, which can not be utilized by the yeast Sacchromyces cerevisiae. The ethanol production by fermentation of corn stover hemicellulosic hydrolysate with a recombinant yeast Sacchromyces cerevisiae ZU-10 was investigated. The effects of three major fermentation inhibitors in hemicellulosic hydrolysate, such as sulfate ion, acetic acid and furfural, on the growth of yeast cells were examined; and it was found that, for the above three inhibitors, the endurable concentration limits of the yeast Sacchromyces cerevisiae ZU-10 cell are 4 g·L·1, 0.25 g·L·1 and 0.08 g·L·1, respectively. With different operation conditions, the hydrolysis processes of the hemicellulose of corn stover were carried out, and the results show that, using 1% sulphuric acid （solid-liquid ratio of 1：10）, 95℃ and 12 h, the hydrolysis yield of hemicellulose can reach 93% with relatively low concentration of inhibitors. The hemicellulosic hydrolysate is available for ethanol production after treating with lime-neutralization, rotor-evaporation and ion-exchange. The sugar concentration of the hemicellulosic hydrolysate correlates with the concentrated degree of the hydrolysate and the concentration of inhibitors in the hydrolysate; and the found suitable sugar concentration of hemicellulosic hydrolysate used for fermentation by the recombinant yeast Sacchromyces cerevisiae ZU-10 is 80 g·L·1. Anaerobic fermentation of the above hemicellulosic hydrolysate was carried out at 30℃ with the inoculums of 1.2 g·L·1 （calculated on dry weight of cells）; after 96 h, the ethanol concentration reaches 31.05 g·L·1., and 95.85% xylose is utilized. The results of this study have great significance for the utilization of hemicellulose resource and accelerating the industrialization progress of producing the bio-ethanol from corn stover.

关 键 词：酒精发酵 木糖 半纤维素 基因重组酵母 玉米秸秆 

分 类 号：TQ92[轻工技术与工程—发酵工程] TQ223.122