Advances on Limonene Microbial Biotransformation and Its Related Enzymes

Limonene,a cheap and widely distributed monoterpene in nature,has important applications in daily chemical,pharmaceutical and food industries. However,due to the unstable chemical property and low aroma value,the application of limonene has certain limitations. The limonene-derived terpenoids have unique aroma and flavor and are used for the production of natural flavors and fragrances,such as α-terpineol,perilly alcohol,carveol. And oxygenated derivatives have high economic value and pharmacological action. The obtention of oxygenated monoterpene can be labeled as "natural" by biotransformation. Biotransformation presents a set of advantages like mild reaction conditions,high efficiency,environmental friendliness and high regio-and enantioselectivity. Thus,biotransformation has emerged as an important approach for producing natural flavors in high quantities. A brief overview of bioconversion products of limonene and summarizes recent advances in biotransformation of limonene was provided. Furthermore,the enzymes involved in the metabolic pathways of limonene were elucidated,especially the cytochrome P450 and hydroxylases. Finally,the development direction of research for realizing industrialization of microbial transformation was summarized.