School of Chemical and Biomolecular Engineering, Pusan National University, San 30, Jangeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea; Nottingham BBSRC/EPSRC Synthetic Biology Research Centre, Centre for Biomolecular Sciences, University Park, The University of Nottingham, Nottingham NG7 2RD, United Kingdom.
School of Chemical and Biomolecular Engineering, Pusan National University, San 30, Jangeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
Bioresour Technol. 2016 Aug;214:432-440. doi: 10.1016/j.biortech.2016.04.032. Epub 2016 Apr 22.
The current study investigates the impact of mutation of 2,3-butanediol (BDO) formation pathway on glycerol metabolism and 1,3-propanediol (PDO) production by lactate dehydrogenase deficient mutant of Klebsiella pneumoniae J2B. To this end, BDO pathway genes, budA, budB, budC and budO (whole-bud operon), were deleted from K. pneumoniae J2B ΔldhA and the mutants were studied for glycerol metabolism and alcohols (PDO, BDO) production. ΔbudO-mutant-only could completely abolish BDO production, but with reductions in cell growth and PDO production. By modifying the culture medium, the ΔbudO mutant could recover its performance on the flask scale. However, in bioreactor experiments, the ΔbudO mutant accumulated a significant amount of pyruvate (>73mM) in the late phase and PDO production stopped concomitantly. Glycolytic intermediates of glycerol, especially glyceraldehyde-3-phosphate (G3P) was highly inhibitory to glycerol dehydratase (GDHt); its accumulation, followed by pyruvate accumulation, was assumed to be responsible for the ΔbudO mutant's low PDO production.
本研究考察了突变 2,3-丁二醇 (BDO) 形成途径对乳酸脱氢酶缺陷突变体克雷伯氏肺炎菌 J2B 甘油代谢和 1,3-丙二醇 (PDO) 生产的影响。为此，从肺炎克雷伯氏菌 J2B ΔldhA 中缺失了 BDO 途径基因 budA、budB、budC 和 budO（全 bud 操纵子），并研究了突变体的甘油代谢和醇（PDO、BDO）生产情况。ΔbudO-突变体只能完全消除 BDO 的产生，但细胞生长和 PDO 产生减少。通过修改培养基，ΔbudO 突变体可以在摇瓶规模上恢复其性能。然而，在生物反应器实验中，ΔbudO 突变体在后期积累了大量丙酮酸（>73mM），同时 PDO 生产停止。甘油的糖酵解中间产物，特别是甘油醛-3-磷酸 (G3P)，对甘油脱水酶 (GDHt) 具有高度抑制作用；其积累，随后是丙酮酸积累，被认为是导致 ΔbudO 突变体 PDO 产量低的原因。
