| 초록 |
3-hydroxypropionic acid (3-HP) can be produced from glycerol via two enzymatic reactions catalyzed by a coenzyme B12-dependent glycerol dehydratase (GDHt) and aldehyde dehydrogenase (ALDH) in Klebsiella pneumoniae. To examine the effect of different ALDH activity on 3-HP production, three different ALDHs, AldH from Escherichia coli (EaldH), PuuC from K. pneumoniae (PuuC) and KGSADH from Azospirillum brasilense (KGSADH), were overexpressed and compared in various recombinant K. pneumoniae strains disrupted the genes encoding DhaT and YqhD. When the ALDH activity was measured, KGSADH showed the highest crude cell activity of 8.0 U/mg protein which was 2 and 4 times higher than that of PuuC and EaldH. In a flask culture containing 100 mM glycerol, K. pneumoniae ∆dhaT (KGSADH) resulted in the highest titer (64 mM). In bioreactor studies, the K. pneumoniae ∆dhaT (KGSADH) showed the 3-HP production at ＞16 g/L in 48 h with a glycerol carbon yield at ＞40%. In comparison, the K. pneumoniae ∆dhaT (PuuC) produced only 11 g/L 3-HP in 48 h with a yield of ＞23%. |
