生物基材料组群知识库

Poly(3-hydroxypropionate) (P3HP) is a biodegradable and biocompatible thermoplastic. Previous studies demonstrated that engineered Escherichia coli strains can produce P3HP with supplementation of expensive vitamin B-12. The present study examined the production of P3HP from glycerol in the recombinant Klebsiella pneumoniae strain, which naturally synthesizes vitamin B-12. The genes glycerol dehydratase and its reactivation factor (dhaB123, gdrA, and gdrB from K. pneumoniae), aldehyde dehydrogenase (aldH from E. coli) were cloned and expressed in K. pneumoniae to produce 3-hydroxypropionate (3HP), with 2 genes (dhaT and yqhD) for biosynthesis of 1,3-propanediol were deleted. To obtain P3HP production, propionyl-CoA synthetase (prpE from E. coli) and polyhydroxyalkanoate synthase (phaC from Ralstonia eutropha) were introduced. Under the appropriate aeration condition, the cell yield and P3HP content were 0.24g/L and 12.7% (wt/wt [cell dry weight]) respectively along with 2.03g/L 3HP after 48h cultivation. Although the yield is relatively low, this study shows the feasibility of producing P3HP in K. pneumoniae from glycerol without vitamin B-12 for the first time. The results also suggest that the aeration conditions should be optimized carefully for the efficient production of P3HP.