Enantioselective hydrolysis of diethyl 3-hydroxyglutarate to ethyl (S)-3-hydroxyglutarate by immobilized Candida antarctica lipase B

Optically pure ethyl (S)-3-hydroxyglutarate [(S)-3-EHG] is used as a key precursor for synthesis of a variety of pharmaceutically important compounds. In this work, we established an efficient procedure for enantioselectively hydrolyzing diethyl 3-hydroxyglutarate (3-DHG) to optically active (S)-3-EHG employing immobilized Candida antarctica lipase B (Novozym 435). Under the optimized conditions: pH 7.0, agitation speed 200 rpm, temperature 40 °C, 3-DHG concentration 0.15 mol L−1, and enzyme loading 7 g L−1, (S)-3-EHG was prepared in above 95% ee value and 98.5% yield, and the reaction was free from external mass transfer and intra-particle diffusion limitations and kinetically controlled. The inhibitions of substrate (3-DHG) and product (3-EHG) were excluded because both displayed no decline in activity at elevated concentrations within the given ranges. In addition, ethanol, a byproduct of the reaction, inhibited lipase B following an uncompetitive inhibition pattern. The kinetic constants were obtained through non-linear regression, with values of Vmax 1.29 mmol min−1 g−1, Km 0.06 mol L−1, and Ki 0.37 mol L−1, respectively.