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

• Published in: Process biochemistry (1991) Vol. 47; no. 7; pp. 1135 - 1143
• Main Authors: Ko, Yeounjoo, Ashok, Somasundar, Zhou, Shengfang, Kumar, Vinod, Park, Sunghoon
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2012
• Subjects: 3-Hydroxypropionic acid; Aldehyde dehydrogenase; Azospirillum brasilense; Escherichia coli; Glycerol; Klebsiella pneumoniae; Glycerol; 3-Hydroxypropionic acid; Aldehyde dehydrogenase; Klebsiella pneumoniae
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2012.04.007

► 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. 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. As the intracellular GDHt activity in K. pneumoniae is high, the overall rate of 3-HP production is controlled by the ALDH activity. 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. In addition, the genes encoding DhaT and YqhD, which are responsible for the conversion of 3-hydroxypropionaldehyde (3-HPA) to 1,3-propanediol (1,3-PDO), were disrupted individually from K. pneumoniae to enhance the carbon flux from 3-HPA to 3-HP. When the ALDH activity was measured in various recombinant K. pneumoniae, KGSADH showed the highest crude cell activity of 8.0U/mg protein, which was 2 and 4 times higher than that of PuuC and EaldH, respectively. The different ALDH activities had a significant effect on 3-HP production in a flask culture containing 100mM glycerol, and K. pneumoniae ΔdhaT (KGSADH) resulted in the highest titer (64mM) among the nine recombinant strains (three ALDH×three host strains; one wild type and two mutants). In glycerol fed-batch bioreactor cultivation, K. pneumoniae ΔdhaT (KGSADH) exhibited 3-HP production at >16g/L in 48h with a glycerol carbon yield of >40%. In comparison, K. pneumoniae ΔdhaT (PuuC) produced only 11g/L 3-HP in 48h with a yield of >23%. This study demonstrates that a high ALDH activity is essential for the effective production of 3-HP from glycerol with recombinant K. pneumoniae.