丁酸梭菌1，3-丙二醇氧化还原酶基因dhaT的克隆及在大肠杆菌中的表达

以丁酸梭菌（Clostridium butyricum）基因组DNA为模板，利用PCR技术扩增得到1，3-丙二醇氧化还原酶基因dhaT，将它连接到pMD18一T载体上，得到重组质粒pMD—dhaT，对此重组质粒进行序列测定，对其DNA序列分析表明，dhaT基因全长为1 158bp。将dhaT基因插入表达载体pSE-380中，构建成重组子pSE—dhaT，并在大肠杆菌JMl09中进行诱导表达。研究表明，以1，3-丙二醇为底物时，基因工程菌在37℃下，以1．0mmol／L IPTG诱导14h，酶活力达到16．28U／mL，比原始菌株提高5、6倍。

Cloning and expression of 1, 3-propanediol oxidoreductase gene from Clostridium butyricum in Escherichia coli

The dhaT gene encoding 1,3-propanediol oxidoreductase （DhaT） was amplified from the ge- nome of Clostridium butyricum by polymerase chain reaction and ligated into pMD 18-T to obtain recombi- nant plasmid pMD-dhaT, which were sent to sequence. It was shown from DNA sequence analysis that the open reading frame of dhaT was 1 158 bp. The gene of dhaT was inserted into expression vector pSE- 380 and the recombinant plasmid pSE-dhaT was constructed and then transformed into E. coli JM109. The results showed that the enzymatic activity of DhaT in crude extracts reached up to 16.28 U/mL when using 1,3-propanediol as substrate under the induced condition of 1.0 mmol/L IPTG at 30 ℃ for 14 hours, and it was increased 5.6 fold compared with that of wild strain.