Synthesis of highly water-soluble feruloyl diglycerols by esterification of an Aspergillus niger feruloyl esterase.

Ferulic acid (FA) is a component of plant cell walls that has applications in food, cosmetic, and health products, but its applications are limited by its high insolubility. We synthesized water-soluble FA derivatives by esterification of FA with diglycerol (DG) using feruloyl esterase purified from a commercial enzyme preparation produced by Aspergillus niger. The major reaction product, FA-DG1, was determined to be γ-feruloyl-α,α'-DG by NMR and electrospray ionization mass spectrometry analyses.

Synthesis of glyceryl ferulate by immobilized ferulic acid esterase.

Glyceryl ferulate was synthesized by the condensation of ferulic acid with glycerol using Pectinase PL "Amano" from Aspergillus niger, which contained ferulic acid esterase, to improve the water-solubility of ferulic acid. The optimum reaction medium was glycerol/0.1 M acetate buffer, pH 4.

Enzymatic synthesis of hydroxycinnamic acid glycerol esters using type A feruloyl esterase from Aspergillus niger.

We found that hydroxycinnamic acid (HA) glycerol esters such as 1-sinapoyl glycerol and 1-p-coumaroyl glycerol can be synthesized through a direct esterification reaction using a type A feruloyl esterase from Aspergillus niger. The water solubilities of HA glycerol esters were higher than those of the original chemicals. HA glycerol esters absorbed ultraviolet light and scavenged 1,1-diphenyl-2-picrylhydrazyl radicals.

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.