Prednisolone production using Pseudomonas fluorescens cells immobilized with polymer carrier produced by radiation polymerization

Pseudomonas fluorescens cells, which convert hydrocortisone to prednisolone, was entrapped in poly-hydroxy ethylmethacrylate (Poly-HEMA) which was prepared by radiation polymerization at low temperature. Using pure poly-HEMA without cross-linking monomer agents increases prednisolone yield to 43.9% compared with the yield produced using polymerized HEMA mixed with N,N'-methylene-bis-acrylamide (36.9%) or 0.1 and 0.2 ml of divinely benzene (39.6 and 26.0%, respectively). Maximal prednisolone productivity (1.83 mg/l/h) was attained using 20 kGy gamma-irradiation for polymerization of HEMA and this was accompanied by lowest productivity of the 20beta-hydroxy-derivative. Prednisolone yield reached 59.8% on increasing the water content of HEMA before polymerization. Maximum prednisolone yield and productivity without formation of 20beta-hydroxy-derivative (64.1 and 2.67 mg/l/h) were recorded using poly-HEMA polymer loaded with 24 h old Ps. fluorescens cells after a 24 h transformation period. The maximum bioconversion efficiency was obtained at a substrate concentration of 20 mg/100 ml medium. Poly-HEMA immobilized Ps. fluorescens cells can be repeatedly used about 12 cycles with gradual increase in the prednisolone yield (76.5-84.3%) by repeated use for 7 times. (C) 2002 Elsevier Science Ltd. All rights reserved.