Figure 1.
Scheme for (R)-HPBA production from OPBA by using a coupled system of reconstructed d-nLDH and FDH.
Table 1.
Strains, plasmids, and oligonucleotide primers used in this study.
Figure 2.
Feasibility of (R)-HPBA production through cofactor regeneration by reconstructed d-nLDH and FDH.
(A) OPBA reduction activities in the crude extract of different E. coli strains. (B) Asymmetric reduction of OPBA by whole cells of different E. coli strains. For E. coli PD, E. coli WD, E. coli D1, and E. coli D2, NADH regeneration was conducted by the direct addition of 50 mM glucose. For E. coli DF, formate of 50 mM was added in the reaction broth for NADH regeneration.
Figure 3.
Optimization of the biocatalysis conditions.
(A) pH. (B) Concentration of OPBA.
Table 2.
Effects of concentration of whole cells on biotransformationa.
Figure 4.
Time course of highly optically pure (R)-HPBA production from OPBA under optimal conditions.
(A) Biotransformation using whole cells of E. coli DF as a biocatalyst and formate for cofactor regeneration. (B) Biotransformation using whole cells of E. coli D2 as a biocatalyst and glucose for cofactor regeneration. (▪), OPBA; (▴), (R)-HPBA; (•), ee.
Table 3.
Comparison of recently reported processes for (R)-HPBA or (R)-HPBE production through bio-reduction.