A Coenzyme‐Independent Decarboxylase/Oxygenase Cascade for the Efficient Synthesis of Vanillin

Abstract

Vanillin is one of the most widely used flavor compounds in the world as well as a promising versatile building block. The biotechnological production of vanillin from plant-derived ferulic acid has attracted much attention as a new alternative to chemical synthesis. One limitation of the known metabolic pathway to vanillin is its requirement for expensive coenzymes. Here, we developed a novel route to vanillin from ferulic acid that does not require any coenzymes. This artificial pathway consists of a coenzyme-independent decarboxylase and a coenzyme-independent oxygenase. When Escherichia coli cells harboring the decarboxylase/oxygenase cascade were incubated with ferulic acid, the cells efficiently synthesized vanillin (8.0 mM, 1.2 g L(-1) ) via 4-vinylguaiacol in one pot, without the generation of any detectable aromatic by-products. The efficient method described here might be applicable to the synthesis of other high-value chemicals from plant-derived aromatics.

Structure and Mechanism of Ferulic Acid Decarboxylase (FDC1) from Saccharomyces cerevisiae

“…Substituted cinnamic acids are abundant molecules in plant lignin polymers and can provide feedstocks for microbial bioprocessing methods aimed at yielding value-added products (2, 3). Degradation of lignin releases ferulic and p-coumaric acids that can be converted to 4-vinylguaicol (4-ethenyl-2-methoxyphenol) and 4-vinylphenol (4-ethenylphenol), respectively, and other hydroxycinnamates can be metabolized to vanillin as a natural flavoring in foods, beverages, and other products (4,5). Related aromatic compounds are also natural components in wine and other fermented beverages and food (6)(7)(8).…”

Enzymatic synthesis of vanillin and related catalytic mechanism

“…with the same enzyme but under the optimal conditions that they had worked out, especially with the addition of H 2 O 2 (as a co‐oxidant) and activated carbon (as an absorbent for the product), both of which have been found to be effective in enhancing the production yield . The conversion obtained in this study is also higher than that obtained using E. coli cells harbouring the decarboxylase/oxygenase cascade (1.2 g L –1 ), and is more than three times as high as that obtained by whole‐cell catalysis with Lysinibacillus fusiformis CGMCC1347 cells as the catalyst (0.7 g L –1 ) …”

“…Although many microorganisms have been studied extensively and a few enzymes in microbial cells have been identified for vanillin production, very few studies have focused on using isolated enzymes for this application. Li et al .…”

An Enzyme Cascade Synthesis of Vanillin

“…Biotransformations with m-cresol (9) and 4-methoxy-2-methylphenol (6) demonstrated that the formation of methylhydroquinone (10) resulted from the conversion of m-cresol (9). No product formation of methylhydroquinone (10) was observed in the transformation of 4-methoxy-2-methylphenol (6). While F87V/A328L showed the highest conversion of 3-methylanisole (1) to intermediate product 3-methoxybenzyl alcohol (2) (9.1%), the highest production of 4-methylguaiacol (3) was achieved with the single variant A328L (2.7%).…”

“…The biotechnological synthesis of vanillin from ferulic acid has gained increasing attention in recent years. Artificial cascades combining a decarboxylase with an oxygenase were developed for the one-pot synthesis of vanillin [6,7]. Aiming at the enzymatic synthesis of vanillin by the selective hydroxylation of an aromatic substrate, cytochrome P450 monooxygenases (P450s) constitute ideal candidates [8].…”