Enantioselective biotransformation of pentoxifylline into lisofylline using wine yeast biocatalysis

Lisofylline (1-(5-R-hydroxyhexyl)-3,5-dimethylxanthine (LSF)) is a new methylxanthine, a stereospecific isomer which is a metabolite of pentoxifylline (1-(5-oxohexyl)-3,5-dimethylxanthine (PTX)). Alcohol dehydrogenases (E.C. 1.1.X.Y.) are enzymes that catalyze the oxidation and reduction of hydroxyl and carbonyl compounds. They may be employed either as crude or purified enzymes or as components of whole cells. The aim of this study was to explore the stereoselective bioreduction of PTX in the presence of whole cell baker's and wine yeasts, which function as biocatalysts in the production of LSF. The experiments were conducted in water and a number of organic solvents (toluene, hexane, ethyl acetate), and we obtained LSF with different yields and ee values. Our research demonstrated that the highest activity is shown when the KKPU strain is used in an aqueous medium. The biotransformation of PTX into LSF in this case was characterized by high yield and enantioselectivity: 95% and ee = 98%, respectively.