earticle

영어

Klebsiella pneumoniae converts glycerol to the specialty chemical 1,3- propanediol (1,3-PDO), which is used for the production of polytrimethylene terepthalate. Here, an NAD+-dependent gamma-glutamyl-gammaaminobutyraldehyde dehydrogenase (PuuC) of K. pneumoniae, which oxidizes 3-hydroxypropionaldehyde to a platform chemical 3-hydroxypropionic acid (3-HP), was overexpressed in K. pneumoniae DSM 2026 for the co-production of 3-HP and 1,3-PDO from glycerol. In addition, the gene dhaT, encoding NADH-dependent 1,3-propanediol oxidoreductase, was deleted from the chromosome for the balanced production of 3-HP and 1,3-PDO. The recombinant K. pneumoniae ΔdhaT, expressing PuuC, produced 3.6 g/L 3-HP and 3.0 g/L 1,3-PDO with an average yield of 81% on glycerol carbon in shake flask culture under microaerobic conditions. When a fed-batch culture was carried out under microaerobic conditions at pH 7.0 in a 5 L bioreactor, the recombinant K. pneumoniae ΔdhaT (puuC) strain produced 16.0 g/L 3-HP and 16.8 g/L 1,3-PDO with a cumulative yield of 51% on glycerol carbon in 24 h. The production of 1,3-PDO in the dhaT-deletion mutant was attributed to the expression of NAD(P)H-dependent hypothetical oxidoreductase. This study demonstrates the feasibility of obtaining two commercially valuable chemicals, 3-HP and 1,3-PDO, at a significant scale.