Feruloyl esterase from Aspergillus sp.: Purification, properties, and action on natural substrates

An enzyme active toward the methyl ester of ferulic acid was isolated from the fungus Aspergillus sp. and purified to homogeneity using ion-exchange a nd hydrophobic chromatography. The molecular weight of the enzyme is 42 kD, and its pi is 3.7. The enzyme has a pH optimum in the range 4-6 and a temp erature optimum in the range 40 to 60 degrees C. Using a number of syntheti c and natural substrates, the enzyme was identified as a feruloyl esterase. The feruloyl esterase did not hydrolyze wheat straw. Ferulic acid was dete cted as a product of hydrolysis of wheat bran and sugar-beet pulp. Other pr oducts were also detected after sugarbeet pulp hydrolysis.