Regarding vanilly-alcohol oxidase, Dr.
Laboratories and Demonstrations; organic chemistry; oxidation; vanillyl alcohol; TEMPO
(Mexican or Bourbon vanilla) and V.
Analytical scale biotransformations were conducted in the same medium as for preparative biotransformations. Suspensions of cells (0.05 g [wet weight]/ml) containing 0.6 mg of 4-O-benzylvanillic acid per ml were incubated at 30°C. Samples (1 ml) taken during the course of incubation received 50 μl of p-anisic acid (4 mg/ml in methanol) as an internal standard. Samples were acidified to pH 2 with 6 N HCl and loaded onto solid-phase extraction cartridges (Chem Elut CE 1001), which were equilibrated for 5 min and then eluted twice with 3 ml of ethyl acetate. Pooled eluates were analyzed by HPLC.
In our laboratory, the mechanism of ferulic acid transformation to vanillic acid by R. rubra IFO 889 occurred by β-oxidation (). The ready availability of vanillic acid by this process, and the discovery of a vanillic acid reduction pathway in Nocardia sp. strain NRRL 5646 suggested the potentials for whole cells or the pure carboxylic acid reductase from this microorganism for vanillin synthesis.
T1 - Enzymatic synthesis of vanillin
The synthesis of vanillin from ferulic acid has been reported with several microorganisms (, , , , ). In P. acidivorans (), manometric studies suggested that vanillin was produced by a two-step reaction including water addition to the cinnamoyl side chain and subsequent retro-aldol condensation to give vanillin. In general, yields were low because vanillin was further oxidized to vanillic acid which was O-demethylated to protocatechuic acid or decarboxylated to guaiacol. The addition of sulfhydryl compounds to ferulic acid transformation medium increased vanillin accumulations by Pseudomonas putida ATCC 55180 (). However, the mechanism by which sulfhydryl reagents improved vanillin yields was not clear. Mulheim and Lerch recently described a relatively high yield direct conversion of ferulic acid to vanillin by cultures of Streptomyces setonii (). With this organism, yields of vanillin were directly proportional to ferulic acid concentrations in culture media.
Many microbial transformation approaches have been used to produce vanillin. In most cases, the yields of vanillin were low, and times for biotransformation reactions are long (, , , , , 28).
T1 - Synthesis of vanillin in water by TiO2 photocatalysis
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.
By HPLC, benzoate-induced cells of Nocardia sp. rapidly transformed 4-O-benzylvanillic acid to metabolites within 40 min (Fig. ). In the first 15 min, the aldehyde 3b accumulated in transient fashion to a maximum 30% yield (175 μg/ml) after which compound 3b was further quantitatively reduced to the corresponding alcohol 4b.
Synthesis of Vanillin by Oxidation of Lignosulfonates
coli de novo vanillin biosynthesis pathway
van Berkel(personal communication, 2001) states, "Vanillyl alcohol is not a growthsubstrate for the fungus.
Synthesis of Vanillin by Oxidation of Lignosulfonates,
tahiten¢sis Moor (Tahitian vanilla) have fruits called vanilla beans which are picked before fully matured.
Vanillyl alcohol: Except where otherwise noted, ..
Vanilla extract contains soluble matter from not less than 10 grams of vanilla beans in 100 milliliters.
Synthesis of Vanillyl Alcohol, ..
We have developed (equation 1) a convenient two step synthesis of vanillin using electrophilic aromatic substitution, followed by an organometallic methoxylation procedure using copper bromide and sodium methoxide.....
Biocatalytic Synthesis of Vanillin
AB - Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated conversion of creosol proceeds via a two-step process in which the initially formed vanillyl alcohol is further oxidized to vanillin. Catalysis is limited by the formation of an abortive complex between enzyme-bound flavin and creosol. Moreover, in the second step of the process, the conversion of vanillyl alcohol is inhibited by the competitive binding of creosol. The VAO-catalyzed conversion Of vanillylamine proceeds efficiently at alkaline pH values. Vanillylamine is initially converted to a vanillylimine intermediate product, which is hydrolyzed nonenzymatically to vanillin. This route to vanillin has biotechnological potential as the widely available principle of red pepper, capsaicin, can be hydrolyzed enzymatically to vanillylamine.
01/07/1999 · Biocatalytic Synthesis of Vanillin
It has thus the potential to become a key-...This paper proposes a perspective article on lignin-derived vanillin for further use as an aromatic building block for chemistry.
Synthesis of Vanillin from Glucose
The conversions of vanillic acid and O-benzylvanillic acid to vanillin were examined by using whole cells and enzyme preparations of Nocardia sp. strain NRRL 5646. With growing cultures, vanillic acid was decarboxylated (69% yield) to guaiacol and reduced (11% yield) to vanillyl alcohol. In resting Nocardia cells in buffer, 4-O-benzylvanillic acid was converted to the corresponding alcohol product without decarboxylation. Purified Nocardia carboxylic acid reductase, an ATP and NADPH-dependent enzyme, quantitatively reduced vanillic acid to vanillin. Structures of metabolites were established by 1H nuclear magnetic resonance and mass spectral analyses.
Vanillin Synthesis from 4-Hydroxybenzaldehyde
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 (, ).
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