Construction and screening of novel recombinant Klebsiella pneumoniae capable of co-producing 3-hydroxypropionic acid and 1,3-propanediol from glycerol

Abstract:

3-HPA was a toxic intermediate metabolite in the 1,3-PD pathway of Klebsiella pneumoniae and its accumulation could inhibit cell growth and glycerol utilization. In order to reduce the 3-HPA accumulation and produce 3-HP simultaneously, the aldh gene from a Saccharomyces cerevisiae en-coding NAD+-dependent acetaldehyde dehydrogenase (ALDH) was cloned and the expression vector pKP-aldh harboring aldh gene was constructed and transformed into K. pneumoniae. The resulting re-combinant strain K. pneumoniae A+ could express the ALDH effectively. The bacteria was mutated by UV lights and screened in 3-HP tolerance plates to yield K. pneumoniae A+5-3. In the fed-batch fermenta-tion of K. pneumoniae A+5-3, the final 3-HP and 1,3-PD concentration reached 5.0 g/L and 74.5 g/L, re-spectively, which were higher than those of wild-type K. pneumoniae.