The bioconversion of waste residues (by-products) from cereal processing industries requires the cooperation of enzymes able to degrade xylanolytic and cellulosic material. The type A feruloyl esterase from Aspergillus niger, AnFaeA, works synergistically with (1→4)-β-d-xylopyranosidases (xylanases) to release monomeric and dimeric ferulic acid (FA) from cereal cell wall-derived material. The esterase was more effective with a family 11 xylanase from Trichoderma viride in releasing FA and with a family 10 xylanase from Thermoascus aurantiacus in releasing the 5,5′ form of diferulic acid from arabinoxylan (AX) derived from brewers’ spent grain. The converse was found for the release of the phenolic acids from wheat bran-derived AXs. This may be indicative of compositional differences in AXs in cereals.