Enantioselective resolution of γ-lactam by a whole cell of Microbacterium hydrocarbonoxydans (L29-9) immobilized in polymer of PVA-alginate-boric acid.

Using immobilized cells of a novel strain of Microbacterium hydrocarbonoxydans L29-9 in polymers of polyvinyl alcohol (PVA)-alginate-boric acid, enantioselective resolution of racemic γ-lactam to produce (-)γ-lactam was successfully carried out. A 6:1 ratio of PVA:sodium alginate not only prevented agglomeration of the matrix but also produced beads with high gel strength. The optimum biotransformation conditions were 1 g/L substrate, pH 7.0, reaction temperature of 30 °C, and reaction time of 3 h. After every two cycles, the immobilized cell beads were separated and immersed in 0.5 mM KCl solution at 4 °C for preservation. At optimum conditions, the enantiomeric excess and the yield of (-)γ-lactam were >99% and 34%, respectively. The beads showed a slight decrease in the enantiomeric excess when re-used up to 14 cycles (the enantioselectivity of the immobilized cells decreased slightly after 14 cycles of usage).