Soil-Plant-Nutrient Research Unit, USDA-ARS, Fort Collins, CO 80526-8119, USA.
Curr Microbiol. 2012 Dec;65(6):752-7. doi: 10.1007/s00284-012-0222-4. Epub 2012 Sep 18.
We investigated the conversion of ferulic acid to 4-vinylguaiacol (4-VG), vanillin, vanillyl alcohol, and vanillic acid by five Enterobacter strains. These high-value chemicals are usually synthesized by chemical methods but biological synthesis adds market value. Ferulic acid, a relatively inexpensive component of agricultural crops, is plentiful in corn hulls, cereal bran, and sugar-beet pulp. Two Enterobacter strains, E. soli, and E. aerogenes, accumulated 550-600 ppm amounts of 4-VG when grown in media containing 1,000 ppm ferulic acid; no accumulations were observed with the other strains. Decreasing the amount of ferulic acid present in the media increased the conversion efficiency. When ferulic acid was supplied in 500, 250, or 125 ppm amounts E. aerogenes converted ~72 % of the ferulic acid present to 4-VG while E. soli converted ~100 % of the ferulic acid to 4-VG when supplied with 250 or 125 ppm amounts of ferulic acid. Also, lowering the pH improved the conversion efficiency. At pH 5.0 E. aerogenes converted ~84 % and E. soli converted ~100 % of 1,000 ppm ferulic acid to 4-VG. Only small, 1-5 ppm, accumulations of vanillin, vanillyl alcohol, and vanillic acid were observed. E. soli has a putative phenolic acid decarboxylase (PAD) that is 168 amino acids long and is similar to PADs in other enterobacteriales; this protein is likely involved in the bioconversion of ferulic acid to 4-VG. E. soli or E. aerogenes might be useful as a means of biotransforming ferulic acid to 4-VG.
我们研究了五种肠杆菌属菌株将阿魏酸转化为 4-乙烯基愈创木酚（4-VG）、香草醛、香草醇和香草酸。这些高价值化学品通常通过化学方法合成，但生物合成增加了市场价值。阿魏酸是农业作物中相对廉价的成分，在玉米皮、谷物麸皮和糖甜菜浆中含量丰富。两种肠杆菌属菌株，E. soli 和 E. aerogenes，在含有 1000ppm 阿魏酸的培养基中生长时积累了 550-600ppm 的 4-VG；其他菌株则没有观察到积累。减少培养基中阿魏酸的含量提高了转化效率。当阿魏酸以 500、250 或 125ppm 的量供应时，E. aerogenes 将存在的阿魏酸的72%转化为 4-VG，而当供应 250 或 125ppm 的阿魏酸时，E. soli 将存在的阿魏酸的100%转化为 4-VG。此外，降低 pH 值可提高转化效率。在 pH 值为 5.0 时，E. aerogenes 将84%和 E. soli 将100%的 1000ppm 阿魏酸转化为 4-VG。只观察到很小的、1-5ppm 的香草醛、香草醇和香草酸的积累。E. soli 有一种假定的酚酸脱羧酶（PAD），长 168 个氨基酸，与其他肠杆菌目中的 PAD 相似；这种蛋白质可能参与阿魏酸向 4-VG 的生物转化。E. soli 或 E. aerogenes 可能可作为将阿魏酸生物转化为 4-VG 的有用手段。
