Enantioselective hydrolysis of (R)-2, 2-dimethylcyclopropane carboxamide by immobilized cells of an R-amidase-producing bacterium, Delftia tsuruhatensis CCTCC M 205114, on an alginate capsule carrier

Immobilized cells of Delftia tsuruhatensis CCTCC M 205114 harboring R-amidase were applied in asymmetric hydrolysis of (R)-2, 2-dimethylcyclopropane carboxamide (R − 1) from racemic (R, S)-2, 2-dimethylcyclopropane carboxamide to accumulate (S)-2, 2-dimethylcyclopropane carboxamide (S − 1). Maximum R-amidase activity of 13.1 U/g wet cells (0.982 U/g beads) was obtained under conditions of 3% sodium alginate, 2.5% CaCl₂, 15 h crosslinking and 2 mm bead size, which was 53.9% of that of free cells (24.3 U/g wet cells). In addition, characterization of the immobilized cells was examined. The optimum R − 1 hydrolysis conditions were identified as follows: substrate concentration 10 mM, pH 8.5, temperature 35°C and time course 40 min. Under optimum conditions, the maximum yield and enantiomeric excess of (R)-2, 2-dimethylcyclopropanecarboxylic acid were 49.5% and >99%, respectively. This afforded S − 1 with a yield >49% and an e.e. of 97.7%. With good operational stability and excellent enanotioselectivity, the immobilized cells could be potentially utilized in industrial production of S − 1.