Microbial Cell Factories for the Biosynthesis of Vanillin and Its Applications

Vanillin is a phenolic aldehyde that is responsible for the production of vanillin aroma. Apart from being an excellent flavoring agent, vanillin also has a wide range of applications in nonfood industries as a polishing agent, deodorant, fruit ripening agent, etc., which have paved way for increasing the market demand of vanillin. Primarily, vanillin is produced from pods of plant Vanilla planifolia , but the production rate was much low, which could not meet the world's demand. Thus, an alternative sources and methods for improving vanillin production are required. Plants aside, vanillin is also produced by various microbes as a secondary metabolite, and this knowledge has led to the development of alternate strategies such as chemical, synthetic, and biotechnological production of vanillin. Sustainable production of vanillin through biotechnological approaches by exploiting the metabolic pathways of microbes has gained renewed attention. This review summarizes the development of vanillin production from natural methods to modern biotechnological strategies. We have highlighted the new trends employed in production process using various microbes as cell factories and the use of agrowaste in vanillin production. Further, the clinical significance of vanillin as antimicrobial, antioxidant, anticarcinogenic, antimutagenic agents, etc., and the applications of vanillin in various industries like pharma, food, and cosmetics are discussed in detail.