Development of an Escherichia coli whole cell catalyst harboring conjugated polyketone reductase from Candida glabrata for synthesis of d-(−)-pantolactone

d -(+)-pantothenic acid (DPA) has been widely used in feed and food additives and pharmaceutical industries. d -(−)-pantolactone ( D PL) is a key intermediate in the production of DPA . The bio-asymmetric synthesis of D PL from ketopantoyl lactone (KPL) by conjugated polyketone reductases is an attractive route. In this study, high expression of a conjugated polyketone reductase from Candida glabrata ( Cgl CPR) in Escherichia coli was achieved after optimization of vectors. The optimum temperature and pH of purified Cgl CPR were 40 °C and 4.5, respectively. The Michaelis-Menten constant K m and V max of purified Cgl CPR for KPL are 73.09 μM and 2.29 μmol mg −1  s −1 , respectively. To circumvent the spontaneous degradation of KPL in biocatalytic reaction of synthesizing DPL, the reaction was performed by a strategy combing fed-batch addition of whole cell catalyst with substrate semi-continuous feeding. At the final KPL loading of 1000 mM, DPL with an isolated yield of 94.24 % was obtained after 13-h reaction and enantiomeric excess ( e.e. ) achieved > 99 %. The space-time yield of DPL reached to 228 g L −1  d −1 .