Effects of enzymatic removal of plant cell wall acylation (acetylation, p-coumaroylation and feruloylation) on accessibility of cellulose and xylan in natural (non-pretreated) sugar cane fractions

Abstract

The central part of the sugar cane internodes (pith) was used as a substrate to evaluate sugar cane digestibility by acessory enzymes combined with cellulases and xylanases. Acetyl xylan esterase (TrAXE) was more efficient in enhancing the overall saccharification of sugar cane as compared to the feruloyl esterases AnFaeA, TsFaeC and NcFaeD. The hydroxycinnamic acid composition of sugar cane fractions and the hydrolysis data together suggest that feruloyl groups are more likely to decorate xylan, while p-coumaroyl groups are rather linked to lignin. The three different feruloyl esterases had distinct product profile on non-pretreated sugar cane substrate, indicating that sugar cane pith could function as a possible natural substrate for feruloyl esterase activity measurements. Hydrolysis data suggest TsFaeC was able to release p-coumaroyl groups esterifying lignin. (AU)