Biological Production of Natural Vanillin Based on the Microbial Conversion of Phenylpropanoids

The rising popularity of natural aroma products has triggered off significant research activities to use biocatalysts for the production of natural flavor compounds. Vanillin is of major interest for the flavor and fragrance industry. It has been widely used as a flavoring agent in foods، perfumes، beverages، pharmaceuticals and medical industries. Two main approaches for the production of natural vanillin are direct extraction from botanical sources and microbial bioconversion. Considering the various applications of vanillin and increasing consumer-led demand for natural vanillin and also due to the fact that the extraction from botanic sources is very time consuming، expensive and does not satisfy the worldwide demand، alternative biotechnological methods for its production are being constantly explored. Microbial bioconversion has been extensively exploited to make modifications in the structure of the organic compounds. Microbial cells can be efficiently used as a eco-friendly biocatalyst in the conversion of substrates as precursors into value-added products. The current review emphasizes the microbial bioconversion routes involved biological production of natural vanillin based on the microbial conversion of henylpropanoids.