ORGANIC COSOLVENT EFFECTS ON THE BIOCONVERSION OF (R)-(-LIMONENE TO (R)-(+)-ALPHA-TERPINEOL())

The effects of 22 organic solvents were tested on the bioconversion of (R)-(+)-limonene to (R)-(+)-alpha-terpineol by free and immobilized P . digitatum mycelia. Free cells showed the highest bioconversion activ ity in water-organic co-solvent single-phase systems. The relative act ivity increased 2.4 fold with dioctylphthalate (1.5%, v/v) and 2.2 fol d with ethyl decanoate (1.5%, v/v). Immobilized cells showed the great est bioconversion in detergent reversed micelle systems. When Tween 80 (0.1%) or Triton 100-X (0.1%) was added into an immobilized P. digita tum bioconversion system, the relative bioconversion activity increase d 2 fold. Immobilization protected the fungal cells from the cytotoxic effects of organic solvents. Dioctylphthalate 1.5% to 2% (v/v) was th e optimum concentration range for free cell bioconversion, and Tween 8 0 0.5% to 1% (v/v) was the optimum concentration range for immobilized cell bioconversion. (C) 1998 Elsevier Science Ltd. All rights reserve d.