[Research advances in biosynthetic pathways of monoterpenes]

Monoterpene compounds are the main components of plant essential oils, which have significant biological activity and wide range, and play an important role in food, cosmetics, medicine and other fields, with high economic value and pharmaceutical potential, and large market demand. Traditional extraction, separation and chemical synthesis methods have problems such as low yield, high cost, and high environmental pressure, which is difficult to meet the growing demand for monoterpenes. With the advancement of sequencing technology and the extensive research on synthetic biology, biosynthesis technology provides a green, efficient and sustainable alternative for the production of monoterpenes. This paper systematically sorts out the known monoterpene biosynthesis pathways, focusing on the regulatory enzymes in each stage of monoterpene biosynthesis pathway, including prenyl diphosphate synthase that catalyzes the formation of monoterpene precursors, the monoterpene synthase catalyzes the main structure of monoterpene, and cytochromes P450 that modify the monoterpene skeleton. The catalytic principles and characteristics of these enzymes in monoterpene biosynthesis were analyzed, and the influencing factors of monoterpene heterologous production were discussed. The purpose of this review is to lay a foundation for a better understanding of the evolution of monoterpene biosynthesis pathway, provide a reference for further analysis of functional enzymes at different stages of monoterpene biosynthesis and their action mechanisms, and point out the direction for the effective use of microorganisms to produce high-value active monoterpene compounds.