Biotechnological Advances in Vanillin Production: From Natural Vanilla to Metabolic Engineering Platforms

Vanillin, an aromatic aldehyde, is one of the most popular flavors worldwide, extensively used in the food, cosmetics, pharmaceutical, and agrochemical industries. Despite its widespread use, less than 1% of the total vanillin production is natural, with the majority being synthesized chemically. While chemical synthesis can help to meet the growing demand for vanillin, a strong market trend has rapidly developed for products created from natural ingredients, including natural vanillin. Given the labor-intensive process of extracting vanillin from vanilla pods, there is a critical need for new metabolic engineering platforms to support the biotechnological production of nature-identical vanillin. This review highlights the significance of vanillin in various markets, its diverse applications, and the current state of bio-engineered production using both prokaryotic and eukaryotic biological systems. Although recent advancements have demonstrated successful vanillin production through biocatalytic approaches, our focus was to provide a current and innovative overview of vanillin bioengineering across various host systems with special consideration placed on microalgae, which are emerging as promising platforms for vanillin production through metabolic engineering. The use of these systems to support the biotechnological production of vanillin, while leveraging the photosynthetic capabilities of microalgae to capture CO2 and convert it into biomass, can significantly reduce the overall carbon footprint.