Purification and characterization of ferulate and p-coumarate decarboxylase from Bacillus pumilus

Bacillus pumilus PS213 isolated from bovine ruminal fluid was able to transform ferulic acid and p-coumaric acid to 4-vinylguaiacol and 4-vinylphenol, respectively, by nonoxidative decarboxylation. The enzyme responsible for this activity has been purified and characterized. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of crude extract from a culture induced by ferulic acid or p-coumaric acid shows three bands that are not present in the crude extract of an uninduced culture, while the purified enzyme shows a single band of 23 kDa; the molecular mass calculated by size exclusion chromatography is 45 kDa. Enzyme activity is optimal at 37 degrees C and pH 5.5 and is not enhanced by any cation. Kinetic studies indicated a Km of 1.03 mM and a Vmax of 0.19 mmol.min-1/mg.liter-1 for ferulic acid and a Km of 1.38 mM and a Vmax of 0.22 mmol.min-1/mg.liter-1 for p-coumaric acid.