Enhanced Fatty Acid Production in Escherichia coli by Over-Expression of NADPH Generating Enzymes
Yuanda Song, Yong Q. Chen, Haiqin Chen, Yongshuang Zhou and Huaiyuan Zhang
American Journal of Biochemistry and Biotechnology
NADPH is an essential factor for Fatty Acid (FA) biosynthesis. The effect of NADPH generating enzymes [NADP+-dependent malic enzyme (NADP-ME), NADP+-dependent isocitrate dehydrogenase (NADP-IDH), Glucose 6-Phosphate Dehydrogenase (GPD) and 6-Phosphogluconate Dehydrogenase (PGD)] on FA biosynthesis was investigated in an engineered Escherichia coli BL21 ?fadE/pTE. Among NADPH-generating enzymes, GPD and ICD increased total FA production by 60 and 16% respectively. Especially medium-chain FA production was increased up to 4.2 and 2.5 folds respectively. In addition, over-expression of the endogenous Thioesterase (TE) reduced Cyclopropane Fatty Acid (CFA) production by 40% and over-expressing of GPD and ICD further decreased CFA production by 23 and 30%, respectively compared to the TE over-expressed strain. Over-expression of TE appeared to be a good strategy to produce high quality biodiesel with medium-chain FAs as major Component (62%) and with Minimal Amount of CFA (4%). This study reveals that NADPH-generating enzyme GPD is associated with FA biosynthesis in E. coli, but not all reducing power generating enzymes, are involved in FA biosynthesis in bacteria.
© 2017 Yuanda Song, Yong Q. Chen, Haiqin Chen, Yongshuang Zhou and Huaiyuan Zhang. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.