Metabolic engineering NADPH metabolism

Kleijn, R.J., Liu, F., Winden, W.A.v. et al. (2007) Cytosolic NADPH metabolism in penicillin-G producing and non-producing chemostat cultures of Penicillium chrysogenum. Metabolic Engineering, 9, 112-123. 

The phbA, phbB, and phbC genes from Alcaligenes eutrophus (Ralstonia eutrophus) encoding the biosynthetic enzymes (3-ketothiolase, acetoacetyl-CoA reductase (NADPH-dependent), and PHB synthase, respectively, have been cloned into E. coli (Scheme 19.42).339-342 The use of in vitro evolution using error-prone polymerase chain reaction has led to enhanced accumulation of PHA in a resultant recombinant strain.343 Additional studies to enhance the biosynthesis of PHB through the use of metabolic engineering have been discussed.344... 

There have been many successful cases of the development of metabolically engineered E. coli strains for the production of P(3HB), which is one of the best characterized PHAs. P(3HB) synthesis is initiated by condensation of two acetyl-CoA molecules into acetoacetyl-CoA, subsequently followed by reduction to 3-hydroxybutyryl-CoA using NADPH as a cofactor, and finally 3-hydroxybutyryl-CoA is incorporated into the growing chain of P(3HB) (Lee 1996). Because the P(3HB) synthesis pathway competes with inherent metabolic pathways needing acetyl-CoA, it is very important to increase the acetyl-CoA pool available for the P(3HB) synthesis reaction, resulting in increased P(3HB) yield and productivity. 

Lee KH, Park JH, Kim TY, Kim HU, Lee SY (2007) Systems metabolic engineering of Escherichia coli for L-threonine production. Mol Syst Biol 3 1-8 Lim SJ, Jung YM, Shin HD, Lee YH (2002) Amplification of the NADPH-related genes zfvf and gnd for the oddball biosynthesis of PHB in an E. coli transformant harboring a cloned phbCAB Operon. J Biosci Bioeng 93 543-549... 

Moreira dos Santos, M., Raghevendran, V., Kotter, R, Olsson, L., Nielsen, J. (2004). Manipulation of malic enzyme in Saccharomyces cerevisiae for increasing NADPH production capacity aerobically in different cellular compartments. Metabolic Engineering, 6912, 363. 

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