Fig. 5
From: Production of enantiopure (R)- or (S)-2-hydroxy-4-(methylthio)butanoic acid by multi-enzyme cascades
One-pot production of (R/S)-HMTBA from l-Met. a A “two stages in one-pot” strategy for the multi-enzyme cascade reaction to produce (R)-HMTBA or (S)-HMTBA using l-Met. b Time courses of the combination of BM and EM1 for producing (R)-HMTBA from l-Met at a 1-L scale using the “two stage in one pot” strategy. c Time courses of the combination of BM and EM2 for producing (S)-HMTBA from l-Met at a 1-L scale using the “two stage in one pot” strategy. For the first stage (0–14 h): a mixture (1 L) of 100 g L−1 L-Met, 20 g L−1 Pvl-AAD whole-cell catalyst, and 20 mM Tris–HCl buffer (pH 7.5) was incubated at 25 °C. For the second stage (14–23 h): adding 20 g L−1 R/S-selective whole-cell catalyst, 140 g L−1 sodium formate, 0.4 mM NAD+. The temperature was adjusted from 25 to 30 °C and pH was controlled at 7.0 by 4 M HCl. Symbols: (orange square) l-Met, (purple circle) KMTB (intermediate), and (blue triangle) (R/S)-HMTBA