Strategies for Improving the Efficiency of Bioprocesses Involving Toxic Compounds

Biotransformation is a broad and constantly growing field of biotechnology, which encompasses enzymatic, microbial and biomimetic catalysis. Use of biocatalysis for some chemical synthesis steps has unique advantages over traditional chemistry, most notably the possibility of achieving higher product selectivity under mild process conditions. This review discusses critical aspects of biotransformation of toxic organic compounds and suggests some guidelines for experimental planning which could significantly impact product yield. The relative effectiveness of bioconversion depends on the characteristics of microbes and their enzymes, nutritional conditions, environmental parameters (T, pH, pO2), exposure to chemicals which can inhibit or induce enzyme levels, effects of extreme environments (e.g., non-aqueous media), and the kind of product isolation techniques used. Some of these and other factors affecting the efficiency of biotransformation as well as the most promising approaches to transformations of troublesome compounds are described. Recent advances in the use of both synthetic and natural porphyrins as biomimetic catalysts for biotechnological purposes and chemical syntheses are also discussed.