Application of Enzymatic Reactions Involving Electron Transfer and Energy Supply for the Production of Useful Chemicals

In recent years, efforts have been made to apply microbial enzymes to bioprocesses with attractive reactions involving electron transfer and energy supply such as reduction reactions, hydroxylation reactions, carbon-carbon bond-forming reactions, and transfer reactions requiring energy such as ATP. In this chapter, we will look at the progress of such novel enzyme tool developments in the reactions of generating hydroxyl groups as examples and also discuss the use of multiple enzyme systems to diversify the bioprocess application. For example, applications of carbonyl reductase-catalyzing bioreduction system, monooxygenation enzymes like cytochrome P450 monooxygenases and Fe(II)/α-ketoglutarate-dependent dioxygenases, and a novel hydratase for the introduction of hydroxyl groups into unsaturated fatty acid are discussed. The use of baker’s yeast cells as energy supply system for carbon-carbon bond formation by aldol condensation reaction is also described. The development of these enzyme systems will bring a breakthrough in future bioprocess development in chemical industry.