Esterification of ferulic acid with polyols using a ferulic acid esterase from Aspergillus niger.
Commercially available enzyme preparations were screened for enzymes that have a high ability to catalyze direct ester-synthesis of ferulic acid with glycerol. Only a preparation, Pectinase PL "Amano" produced by Aspergillus niger, feruloylated glycerol under the experimental conditions. The enzyme responsible for the esterification was purified and characterized. This enzyme, called FAE-PL, was found to be quite similar to an A. niger ferulic acid esterase (FAE-III) in terms of molecular mass, pH and temperature optima, substrate specificity on synthetic substrates, and the N-terminal amino acid sequence. FAE-PL highly catalyzed direct esterification of ferulic acid and sinapinic acid with glycerol. FAE-PL could feruloylate monomeric sugars including arabinose, fructose, galactose, glucose, and xylose. We determined the suitable conditions for direct esterification of ferulic acid with glycerol to be as follows: 1% ferulic acid in the presence of 85% glycerol and 5% dimethyl sulfoxide at pH 4.0 and 50 degrees C. Under these conditions, 81% of ferulic acid could be converted to 1-glyceryl ferulate, which was identified by (1)H-NMR. The ability of 1-glyceryl ferulate to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was higher than that of the anti-oxidant butyl hydroxytoluene.
Tsuchiyama
Moriyasu
M
Department of Research and Development, Okumoto Flour Milling Co. Ltd., Osaka 550-0015, Japan.
Sakamoto
Tatsuji
T
Fujita
Tomoyuki
T
Murata
Shuichi
S
Kawasaki
Haruhiko
H
D000975:Antioxidants / Q000737:chemistry; D001234:Aspergillus niger / Q000201:enzymology*; D001713:Biphenyl Compounds / Q000737:chemistry; D002384:Catalysis; D003373:Coumaric Acids / Q000737:chemistry*; D004950:Esterases / Q000737:chemistry*; D005609:Free Radicals; D005990:Glycerol / Q000737:chemistry; D006834:Hydrazines / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D050178:Monoglycerides / Q000737:chemistry*; D010851:Picrates; D011108:Polymers / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D013696:Temperature
D000975:Antioxidants; D001713:Biphenyl Compounds; D003373:Coumaric Acids; D005609:Free Radicals; D006834:Hydrazines; D050178:Monoglycerides; D010851:Picrates; D011108:Polymers; C531553:glyceryl ferulate; C024617:polyol; C004999:ferulic acid; C004931:1,1-diphenyl-2-picrylhydrazyl; D004950:Esterases; D005990:Glycerol