The enantioselective catalytic hydrolysis of racemic 1,2-epoxyoctane in a batch and a continuous process

In this study, the effect of the two co-solvents, acetonitrile (MeCN) and e thanol (EtOH), on the solubility of 1,2-epoxyoctane (epoxide), and on the r eactivity of the catalytic hydrolysis to 1,2-octanediol (diol) by Rhodospor idium toruloides was investigated for final application in a flow-through b ioreactor. The solubility of epoxide increased exponentially with the addit ion of both EtOH and MeCN. However, this increased solubility was at the co st of the reactivity of the enzyme, which showed a decrease with increasing co-solvent concentration, most predominant for MeCN. At 20% EtOH the solub ility increased from about 6 to 10 mM, while the initial reaction rate has approximately halved, however, without loss in selectivity. When increasing the epoxide concentration (from 2 to 100 mM) at 20% EtOH, there is an init ial linear increase in the initial production rate of the diol (V-diol) whi ch reaches a plateau at 40 mM. There is a dip in V-diol at around 9 mM, ind icating the possible effect of the one- and two-phase system. In the flow-t hrough bioreactor, a %ee of 35 and 46% was achieved for the (S)-epoxide and (R)-diol, respectively. (C) 2001 Elsevier Science B.V. All rights reserved .