Improved (R)-phenylacetylcarbinol production with Candida utilis pyruvate decarboxylase at decreased organic to aqueous phase volume ratios

Abstract

The effect of decreasing the organic (octanol) to aqueous phase volume ratio was evaluated in a two-phase enzymatic process for (R)-phenylacetylcarbinol (PAC) production. Decreasing the ratio from 1:1 to 0.43:1 at 4 degrees C increased PAC in the organic phase from 112 g/l to 183 g/l with a 10% improvement in overall productivity. Interestingly, the rate of enzyme (pyruvate decarboxylase) activity loss was unaffected by the reduced phase ratio over the reaction period (48 h). At 20 degrees C and 0.43:1 phase ratio the organic phase PAC concentration increased to 212 g/l and the overall productivity increased by 30% although the PAC yield (based on pyruvate) declined by about 10% due to greater byproduct acetoin formation at the higher temperature. Product recovery in such a system is facilitated both by the higher PAC concentration and the reduced organic phase volume.