摘要:
In this experiment,Cupriavidus necator GabD4 and Azospirillum brasilense KGSADH aldehyde dehydrogenase genes were cloned by polymerase chain reaction (PCR),and the resulting PCR products were ligated to plasmid pUC19Kan whose ampicillin resistance had been modified to kanamycin resistance.Then,the recombinant plasmids were transformed into Klebsiella pneumoniae DSM2026,and designated KpKan/KGSADH and KpKan/GabD4.Through shake-flask fermentation,their maximum 3-hydroxy propionic acid (3-HP) yield reached 3.66 and 2.56 g/L respectively,which was 352% and 216% higher than that of the control strain.In addition,analysis of other products showed that 1,3-propylene glycol (1,3-PDO) contents in both recombinant strains were lower whereas 2,3-butylene glycol(2,3-BD) and acetic acid contents were higher than those of the control strain.This is the first report regarding the introduction of C.necator GabD4 aldehyde dehydrogenase into K.pneumoniae and comparing the 3-HP yield between KpKan/KGSADH and KpKan/GabD4,the obtained results are great interest for further improvement of 3-HP production.%PCR扩增Cupriavidus necator GabD4和Azospirillum brasilense KGSADH醛脱氢酶基因,分别与经改造获得卡那霉素抗性的pUC19质粒(pUC19Kan)连接,再转化至Klebsiella pneumoniae DSM2026,获得重组菌KpKan/KGSADH和KpKan/GabD4.经摇瓶发酵,KpKan/KGSADH和KpKan/ GabD4的最高3-羟基丙酸(3-HP)产量分别为3.66与2.56 g/L,与未导入醛脱氢酶的K.pneumoniae对照菌相比,分别提高了352%与216%.对其他产物的研究表明,2株重组菌的1,3-丙二醇(1,3-PDO)的产量低于对照菌,而2,3-丁二醇(2,3-BD)和乙酸产量高于对照菌.该研究首次将C.necator GabD4醛脱氢酶基因导入K.pneumoniae,并对比了KpKan/KGSADH与Kp-Kan/ GabD4的3-HP产量,实验中确定的性能优良的发酵菌株为继续提高3-HP产量提供了帮助.