Chemists create a domestic technology for vanillin synthesis
Vanilla is one of the most widely used flavors in food industry. Natural vanilla extracted from the cured pods of the flowers of Vanilla planifolia has an estimated net value of more than $ 1 billion annually (). Vanillin (3-methoxy-4-hydroxybenzaldehyde) is the most important organoleptic component in vanilla. More than 12,000 tons of synthetic vanillin are produced each year from petrochemical and wood pulping industries (). Strong market demand for natural and environmentally friendly products has spawned efforts to produce vanillin by microbial transformation from natural substrates, including phenolic stibenes (), eugenol (, ), and ferulic acid (, ).
ortho-guaiacol, 90-05-1 - The Good Scents Company
It is possible to envision an enzymatic synthesis of vanillin beginning either with ferulic acid (, , ) or with vanillic acid as the starting materials. Such approaches are attractive because the natural carboxylic acid starting materials are abundant and inexpensive and are soluble in aqueous media. Furthermore, reductions of carboxylic acids to aldehydes are difficult to achieve by chemical means, and the reduction of vanillic acid to vanillin has not been widely reported.
In the preparative scale incubation reaction, TLC analysis indicated that benzoate-induced Nocardia cells produced two major metabolites corresponding to 4-O-benzylvanillin (compound 3b, 170 mg, 24% yield) and 4-O-benzylvanillyl alcohol (compound 4b, 210 mg, 30% yield). These products were spectrally and chromatographically comparable to synthetic compounds 3b and 4b. Thus, 4-O-benzylvanillic acid was reduced first to the aldehyde 3b and subsequently to the alcohol 4b (Fig. ). To confirm the identity of compound 3b, chemical removal of the benzyl group from the microbial metabolite gave 65 mg of vanillin identified by spectral and chromatographic comparisons with authentic vanillin.