Biocatalytic reductions by plant tissue - Green alternative to alcohol production

Abstract

The use of biocatalysts for the industrial synthesis of chemicals has been attracting much attention as an environmental friendly synthetic method. Various plants, such as apple (Malus pumila), carrot (Daucus carota), cucumber (Cucumis sativus), onion (Allium cepa), potato (Solanum tuberosum), radish (Raphanus sativus) and sweet potato (Ipomoea batatas) were used as biocatalysts. Enzymes that plants produce are able to perform reactions under mild conditions (pH and temperature), with remarkable chemo-, regio-, and stereoselectivity. Due to this feature the number of biocatalysts used in organic synthesis has rapidly increased during the last decades, especially for the production of chiral compounds. This review presents biotechnological processes for the production of chiral alcohols by reducing prochiral ketones with whole plant tissue. Chiral alcohols are important building blocks for the synthesis of pharmaceuticals, pesticides, pheromones, flavors, fragrances and advanced materials such as liquid crystals. Reductase-catalyzed reactions are dependent on cofactors, and therefore, one major task in process development is to provide an effective method for regeneration of the cofactors consumed. The need for expensive cofactors is eliminated by using the whole plant tissue since the plant automatically provides this requirement. Depending on the vegetable used, either enantiomer may be obtained in high yield and high enantiomeric excess (ee), which could be a critical factor for drug development/bioactivity evaluation perspective. In this paper, various processes carried out on laboratory scales are presented. Attention is turned to conversion, yield, enantiomeric excess (ee).