Production of l(+)-lactic acid by immobilized cells of Rhizopus oryzae with polymer supports prepared by γ ray induced polymerization

Abstract Rhizopus oryzae cells producing l (+)-lactic acid were immobilized with polymer supports prepared from polyethyleneglycol (no. 400) dimethacrylate as a monomer by γ ray induced polymerization. The production of lactic acid by immobilized cells was influenced by both water content and the support structure. A feasible polymer support had a water content greater than about 80% and a porous structure. The positive effect of immobilization on lactic acid production was found when the immobilization yield was greater than 65%. The specific rate of lactic acid production from immobilized cells reached a value 1.8 times higher than that of free cells.