title: Improving acetyl-CoA biosynthesis inSaccharomyces cerevisiaevia the overexpression of pantothenate kinase and PDH bypass.
abstract: BACKGROUND
  Acetyl-CoA is an important precursor inSaccharomyces cerevisiae. Various approaches have been adopted to improve its cytosolic level previously with the emphasis on engineering the "acetyl-" part of acetyl-CoA. To the best of our knowledge, there have been no reports on engineering the "-CoA" part so far.
  
  
  RESULTS
  In this study, we had tried to engineerS. cerevisiaefrom both the "-CoA" part via pantothenate kinase overexpression (PanK fromS. cerevisiae, the rate-limiting enzyme for CoA synthesis) and the "acetyl-"part through PDH bypass introduction (ALD6fromS. cerevisiaeand SeAcsL641PfromSalmonella enteric). A naringenin-producing reporter strain had been constructed to reflect cytosolic acetyl-CoA level as acetyl-CoA is the precursor of naringenin. It was found that PanK overexpression or PDH bypass introduction alone only led to a twofold or 6.74-fold increase in naringenin titer, but the combination of both (strain CENFPAA01) had resulted in 24.4-fold increase as compared to the control (strain CENF09) in the presence of 0.5 mM substratep-coumaric acid. The supplement of PanK substrate pantothenate resulted in another 19% increase in naringenin production.
  
  
  CONCLUSIONS
  To greatly enhance acetyl-CoA level in yeast cytosol, it is feasible to engineer both the "acetyl-" part and the "-CoA" part simultaneously. Insufficient CoA supply might aggravate acetyl-CoA shortage and cause low yield of target product.
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore.
authors.forename: Wenshan
authors.initials: W
authors.lastname: Liu
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Jiang
keywords: Acetyl-CoA; Naringenin production; Pantothenate; Pantothenate kinase; Pyruvate dehydrogenase bypass; Saccharomyces cerevisiae