Shen Yu, Zhang Yan, Ma Tao, Bao Xiaoming, Du Fengguang, Zhuang Guoqiang, Qu Yinbo
State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, PR China.
Bioresour Technol. 2008 Jul;99(11):5099-103. doi: 10.1016/j.biortech.2007.09.046. Epub 2007 Oct 31.
To reduce the cellobiose inhibition of exoglucanase and endogulcanase and enhance cellulose hydrolysis during simultaneous saccharification and fermentation (SSF), a beta-glucosidase encoding gene named BGL1 was cloned from Saccharomycopsis fibuligera and integrated into the chromosomal rDNA region of the Saccharomyces cerevisiae industrial strain NAN-27 producing NAN-227. Compared with the parental strain, which had no detectable activity, the beta-glucosidase specific activity in NAN-227 was 1.02 IU/mg of protein. When cellobiose was used as the sole carbon source in a shake-flask, NAN-227 consumed 6.2g/L of cellobiose and produced 3.3g/L of ethanol in 48 h. The yield was 0.532 g/g. The parent strain only consumed 1.92 g/L of cellobiose and no ethanol was detected. During the SSF of acid-pretreated corncobs NAN-227 produced 20 g/L of ethanol at 72 h, which was similar to the parent strain when 20IU of beta-glucosidase/g of substrate was added.
为了减少纤维二糖对外切葡聚糖酶和内切葡聚糖酶的抑制作用，并在同步糖化发酵（SSF）过程中增强纤维素水解，从扣囊复膜孢酵母中克隆了一个名为BGL1的β-葡萄糖苷酶编码基因，并将其整合到酿酒酵母工业菌株NAN-27（产NAN-227）的染色体rDNA区域。与无检测活性的亲本菌株相比，NAN-227中的β-葡萄糖苷酶比活性为1.02 IU/mg蛋白质。当在摇瓶中以纤维二糖作为唯一碳源时，NAN-227在48小时内消耗了6.2g/L的纤维二糖，并产生了3.3g/L的乙醇。产率为0.532 g/g。亲本菌株仅消耗了1.92 g/L的纤维二糖，未检测到乙醇。在酸预处理玉米芯的同步糖化发酵过程中，NAN-227在72小时时产生了20 g/L的乙醇，这与添加20IUβ-葡萄糖苷酶/g底物时的亲本菌株相似。
