酿酒酵母代谢木糖工程菌的构建

摘要

Xylose reductase and xylitol dehydrogenase from Candida shehatae amplified by PCR were ligated to yeast expression vector pYES2,to establish recombinant expression vectors pYES2-XYL1 and pYES2-XYL2,respectively. Recombinant expression vector pYES2-XYL1-XYL2 which was acquired by legating XYL1 harboring GAL1 promoter cloned from pYES2-XYL1 to pYES2-XYL2 downstream was transformed to Saccharomyces cerevisiae host strain INVSc1 by electroporation.The ethanol yield was 33.45 g/L under the conditions;initial pH5.5,temperature at 33℃,rotation speed at 50r/min after 150 r/min for 5 h.%通过PCR方法从休哈塔假丝酵母基因组DNA中克隆得到木糖还原酶（XR）基因XYL1和木糖醇脱氢酶（XDH）基因XYL2,将其分别连接到酵母表达载体pYES2上,得到重组表达载体pYES2-XYL1和pYES2-XYL2,从pYES2-XYL1上克隆得到含半乳糖启动子的XYL1,将其连接到pYES2-XYL2序列的下游,得到重组表达载体pYES2-XYL1-XYL2,通过电转化方法将pYES2-XYL1-XYL2转入酿酒酵母宿主菌INVSc1。在初始pH为5.5,温度为33℃,前5h转速为150r/min,后变为50r/min的条件下,乙醇产量为33.45g/L。