The present review compiles the up-to-date knowledge on vanillin biosynthesis in plant systems to focus principally on the enzymatic reactions of in planta vanillin biosynthetic pathway and to find out its impact and prospect in future research in this field.
Vanillin, a very popular flavouring compound, is widely used throughout the world. The principal natural resource of vanillin is the cured vanilla pods. Due to the high demand of vanillin as a flavouring agent, it is necessary to explore its biosynthetic enzymes and genes, so that improvement in its commercial production can be achieved through metabolic engineering. In spite of significant advancement in elucidating vanillin biosynthetic pathway in the last two decades, no conclusive demonstration had been reported yet for plant system. Several biosynthetic enzymes have been worked upon but divergences in published reports, particularly in characterizing the crucial biochemical steps of vanillin biosynthesis, such as side-chain shortening, methylation, and glucoside formation and have created a space for discussion. Recently, published reviews on vanillin biosynthesis have focused mainly on the biotechnological approaches and bioconversion in microbial systems. This review, however, aims to compile in brief the overall vanillin biosynthetic route and present a comparative as well as comprehensive description of enzymes involved in the pathway in Vanilla planifolia and other plants. Special emphasis has been given on the key enzymatic biochemical reactions that have been investigated extensively. Finally, the present standpoint and future prospects have been highlighted.
KeywordsVanillin Side-chain shortening reaction Vanillin synthase Methyltransferase
Caffeic acid O-methyltransferase
The author acknowledges the Indian Institute of Technology Kharagpur for permitting to access the digital library and for providing ‘Institutional Assistantship’ during preparing the manuscript. Author also acknowledges Ms. Shruti Mishra, M.Sc. for helping in linguistic editing of the article.
- Gasson MJ, Kitamura Y, McLauchlan WR, Narbad A, Parr AJ, Parsons ELH, Payne J, Rhodes MJC, Walton NJ (1998) Metabolism of ferulic acid to vanillin: a bacterial gene of the enoyl-SCoA hydratase/isomerase superfamily encodes an enzyme for the hydration and cleavage of a hydroxycinnamic acid SCoA thioester. J Biol Chem 273:4163–4170CrossRefPubMedGoogle Scholar
- Havkin-Frenkel D, Podstolski A, Dixon R (2003) Vanillin biosynthetic pathway enzyme from Vanilla planifolia. United States patent application publication. https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US20030070188.pdf
- Kundu A, Jawali N, Mitra A (2012) Shikimate pathway modulates the elicitor-stimulated accumulation of fragrant 2-hydroxy-4-methoxybenzaldehyde in Hemidesmusindicusroots. Plant PhysiolBiochem 56:104–108Google Scholar
- Tokoro K, Kawahara S, Amano A, Kanisawa T, Indo M (1990). In: Bessiere Y, Thomas AF (eds) Flavour science and technology, vol 73. Wiley, Chichester, p 73Google Scholar
- Zenk MH (1965) Biosynthese von vanillin in Vanilla planifolia. Andr Z Pflanzenphysiol 53:404Google Scholar