초록 |
Klebsiella pneumoniae, which overexpresses aldehyde dehydrogenase (ALDH), can coproduce 3-hydroxypropionic acid (3-HP) and 1,3-propanediol (PDO) from glycerol. In the present study, the lactate dehydrogenase-deficient (ldhA-) recombinant K. pneumoniae overexpressing an ALDH (KGSADH) was developed and the co-production of 3-HP and PDO from glycerol by this recombinant under resting cell conditions was examined. The new recombinant did not produce any appreciable lactate, which seriously inhibits the production of 3-HP and PDO. The final titers of 3-HP and PDO by the ldhA- recombinant strain at 60 h were 252.2 mM and 308.7 mM, respectively, which were improved by approximately 30 and 50%, respectively, compared to those by the counterpart recombinant strain, which was the wild type for ldhA. In addition, after deleting ldhA, the cumulative yield on glycerol and specific production rate of these two metabolites (3-HP and PDO) were enhanced by 41.4% and 52%, respectively. |