Design of biotransformation processes: use of a knowledge-based system

Biotransformations have attracted much industrial and academic interest in the last decade as a means of complementing chemical techniques to synthesize optically pure molecules (for the manufacture of pharmaceutical and agrochemical products) and develop more environmentally-compatible processes. In this paper the use of a Knowledge-Based System (KBS) designed to speed up the process selection and design stages for a relevant biotransformation is described. The underlying framework of rules and decision trees is discussed with particular emphasis on heuristics to guide process design. This is illustrated with examples of rules and heuristics based on a range of biotransformation studies including aromatic hydroxylation to the corresponding dihydrodiol by Pseudomonas putida UV4, menthyl acetate hydrolysis to menthyl alcohol by Bacillus subtilis and pig liver esterase, and hydrocortisone Δ¹–dehydrogenation to prednisolone by Arthrobacter simplex.