Applications of microwaves in biological sciences [Review]

摘要

Microwave irradiation can alter the rate of enzyme-catalysed reactions, although the,role of any non-thermal factors in such processes is controversial. While the studies in aqueous buffers have been understandably limited to thermostable enzymes, higher stability of enzymes in anhydrous media allows the use of a variety of enzymes. The microwave-assisted applications described in this review include use of lipases for esterification and transesterification reactions, protease for peptide synthesis and again, use of two well-known proteases, alpha-chymotrypsin and subtilisin Carlsberg in esterification and transesterification reactions respectively. In the last system, it has been shown that the so-called non-thermal effects increase the reaction rates by 2-5 fold at all water-activity levels. It is also established that microwave irradiation can be used in conjunction with other strategies (like pH tuning and salt activation) for enhancing reaction rates. In addition, some miscellaneous applications in bioanalysis, food processing and extraction of biological materials have been described. Two illustrations for possible use of microwaves in medicine have been briefly discussed. Finally, the review also discusses the recent work on enhancing the rates of enzymatic reactions by pretreatment of insoluble substrates with controlled microwave irradiation.