Aldehyde dehydrogenase activity is important to the production of 3-hydroxypropionic acid from glycerol by recombinant Klebsiella pneumoniae

► 3-HP production from glycerol by K. pneumoniae is dependent on the activity of ALDH. ► KGSADH was the most efficient enzyme in 3-HP production among the ALDHs used here. ► To enhance 3-HP production, competing enzymes, DhaT and NADPH-HOR were eliminated. ► dhaT gene deletion had a significant effect on 3-HP production than yqhD deletion. ► DhaT is the major enzyme, which is involved in 1,3-PDO production by K. pneumoniae.