木酮糖激酶表达水平对酿酒酵母木糖代谢产物流向的影响  

Effect of Xylulokinase Expression-level in The Xylose-utilizing Recombinant Sacchaomyces cerevisiae on The Metabolic Pathway of Xylose

作　　者：沈煜[1] 郑华军[1] 王颖[1] 鲍晓明[1] 曲音波[1] 白凤武[2] 

机构地区：[1]山东大学微生物技术国家重点实验室,济南250100 [2]大连理工大学环境与生命学院,大连116023

出　　处：《生物化学与生物物理进展》2004年第8期746-751,共6页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金委员会与中国节能投资公司联合研究基金资助项目 ( 5 0 2 73 0 19);山东大学微生物技术国家重点实验室开放基金项目~~

摘　　要：在酿酒酵母中分别引入真菌和细菌的木糖代谢关键酶 ,木糖还原酶基因XYL1、木糖醇脱氢酶基因XYL2和木糖异构酶基因xylA .并在此基础上以共转化策略超表达下游关键酶木酮糖激酶基因XKS1.与亲本菌株相比 ,用pMA91和YEp2 4质粒表达XKS1的重组菌株 ,木酮糖激酶 (xylulokinase,XK)活性分别提高了 14和6 7倍 .在限氧条件下 ,重组菌株对木糖和葡萄糖的共发酵结果显示 ,表达XYL1,XYL2以及XKS1的重组菌株HSXY 2 5 1木糖消耗为 12 4 g/L ,提高了 12 0 9% ,乙醇产量达到 9 4 g/L ,提高了 36 % ,副产物木糖醇产量为 0 7g/L ,下降了 84 9% .The xylulokinase gene XKS1 was cloned from Saccharomyces cerevisiae NAN-27 and ligated into plasmids pMA91 and YEp24, producing pMA-xy203 and YEpP-xy204, respectively. In both plasmids, XKS1 was under the control of PGK promoter. pMA-xy203 was transferred into the pre-constructed recombinant yeast strain H158-XR-XDH, which contains the XYL1 and XYL2 genes from Pichia stipitis, encoding xylose reductase and xylitol dehydrogenase respectively, in an episomal plasmid vector. This new recombinant strain was named HSXY-251. YEpP-xy204 was transferred into the pre-constructed recombinant yeast strain H158-XI, which contains the xylA gene from Thermus thermophilus encoding xylose isomerase in an episomal plasmid vector, resulting in recombinant strain HSXY-252. The xylulokinase activities in HSXY-251 and HSXY-252 were respectively 14 and 6.7 times higher than that in the parent strain. Glucose and xylose co-fermentation carried out with HSXY-251 under oxygen-limited conditions at 30degreesC resulted in 9. 4 g/L ethanol concentration with 12. 4 g/L xylose consumed. Xylose consumption and ethanol production were respectively 120. 9% and 36% higher than in the parent strain. Furthermore, the by-product xylitol was 0. 7 g/L, a decrease of 84. 9%.

关 键 词：木糖 木酮糖激酶 酿酒酵母 代谢产物 乙醇 

分 类 号：Q936[生物学—微生物学] TS261.11[轻工技术与工程—发酵工程]