Research Progress in Microbial Metabolic Engineering for Producing Monoterpene Aroma Products

Monoterpenes are an important class of plant natural products that exhibit a broad range of biological activities. Some monoterpenes and related derivatives have shown great potential for various industrial applications (e.g., one of the world’s most commonly used flavour and fragrance additives in foods, medicines and cosmetics), which lead to an increasing market demand for them. However, the low abundance or yield of most monoterpenes and derivatives in plants renders their isolation from plant sources non-economically viable. To meet the rapidly rising market demand for monoterpenes and derivatives, producing them by engineering microbial cells into microbial factories is becoming an attractive alternative approach which can overcome the aforementioned bottleneck, making it more sustainable and environmentally friendly. In recent years, these value-added products have successfully been obtained using metabolically engineered microbes. Here the latest examples of biosynthesis of monoterpene aroma products in the engineered microbes are reviewed . Furthermore, the current bottleneck issues and potential solutions are discussed. It is believed that the information provided here will make a significant contribution to further advancement of the microbial production of monoterpene aroma products through metabolic engineering.