Ferulate side chains are found in cereal and hardwood xylans, as well as in many types of pectin. In xylan, they are ester-linked to the C-2 position of the arabinose side chain of the xylan backbone, where they function as crosslinkers through ether linkages to either ferulic acid on another xylan chain or to lignin components (79). This provides some three­dimensional stability to the polymer network (80). Ferulic acid esterases (FAEs) are active in cleaving ferulic acid from these polymers, though the specificity is again not clear. Some have been reported to act on coumaric as well as ferulic acid (81). Some are preferentially active on polymers while others are more active on substituted xylo-oligomers. There are also reports of FAEs having activity on both ferulated xylan and ferulated pectin (82). Atomic force microscopy studies have suggested that hydrolysis of ferulic acid bridges results in shorter, less-branched xylan chains (83). Other studies have reinforced the synergy between xylanase and FAE, including enhanced synergy in an FAE/xylanase fusion protein (11, 67, 84-86).