Release of Ferulic Acid from Oat Hulls byAspergillusFerulic Acid Esterase andTrichodermaXylanase

Abstract

Oat hulls, an agricultural byproduct, contain a relatively high amount of ferulic acid (FA; 4-hydroxy-3-methoxycinnamic acid), which is believed to be inhibitory to oat hull biodegradability by rumen microorganisms. In this paper, Aspergillus ferulic acid esterase (FAE) was investigated for its ability to release FA from oat hulls. The objectives were to determine the effects of particle size of oat hulls (ground to pass through 1 mm and 250 microm screens and a 100 microm sieve) on release of FA by FAE both in the presence and in the absence of Trichoderma xylanase. The results show that the release of FA by FAE was dependent upon the particle size of oat hulls (< or = 250 microm). In the absence of Trichoderma xylanase, little FA was released by FAE. In the presence of Trichoderma xylanase, there was a significant release of FA by FAE, indicating a synergistic interaction between FAE and Trichoderma xylanase on release of FA from oat hulls. These results indicate that FAE is able to break the ester linkage between FA and the attached sugar, releasing FA from oat hulls. This may leave the remainder of the polysaccharides open for further hydrolytic attack by rumen microorganisms. It is likely that removing FA from oat hulls could improve rumen biodegradability, thus improving the nutritional value of oat hulls.

The interactive effects of enriched sources of Aspergillus ferulic acid esterase and Trichoderma xylanase on the quantitative release of hydroxycinnamic acids from oat hulls

“…The present and previous investigations (Yu et al 2000(Yu et al , 2002 have shown that a ferulic acid esterase, A-FAE, had no detectable activity toward oat hulls that were ground to pass through a 1-mm screen, but had low levels of activity toward very finely ground (250 and 100 µm) oat hulls, suggesting that substrate size and/or accessibility impedes enzyme activity.…”

“…Oat hulls contain relatively high amounts of hydroxycinnamic acids, mainly ferulic acid (3-methoxy-4-hydroxycinnamic acid) and p-coumaric acid (4-hydroxycinnamic acid) (Garleb et al 1987(Garleb et al , 1991 at levels of 0.4 to 0.5% and 0.3 to 0.4%, respectively (Garleb et al 1991;Yu et al 2000Yu et al , 2002. They are covalently cross-linked to polysaccharides by ester bonds and to components of lignin, mainly by ether bonds (Scalbert et al 1985;Borneman et al 1991).…”

“…Previous research (Yu et al 2002) has shown that release of ferulic acid and p-coumaric acid by enriched sources of Aspergillus ferulic acid esterase (A-FAE) was dependent upon particle size (≤ 250 µm) of oat hulls and the presence of an enriched source of Trichoderma xylanase (T-XYL). Several other studies have also shown that efficient release of ferulic acid and/or p-coumaric acid is not only dependent on substrate particle size (Borneman et al 1991), but also on the presence of other cell wall degrading enzymes such as xylanase Bartolomé and Gómez-Cordovés 1999).…”

Production of cellulolytic enzymes containing cinnamic acid esterase from Schizophyllum commune

“…Treatment with this enzyme preparation can effectively release the cinnamic acid derivatives. Some studies have demonstrated that a combination of ferulic acid esterase and endoxylanase released ferulic acid from de-starched wheat bran (Faulds and Williamson, 1991) and oat hulls (Yu et al, 2002(Yu et al, , 2003. Therefore, the fi ndings of the present study indicate enzyme preparations from S. commune may provide a novel method for utilization of unused agricultural wastes.…”

Hydroxycinnamic acids and ferulic acid esterase in relation to biodegradation of complex plant cell walls

“…In monocots, ferulic acid is esterified to the C-5 hydroxyl group of arabinofuranose residues of arabiboxylans (Colquhoun et al 1994;Ralet et al 1994;Saulnier et al 1995b;Ishii 1997;Wende and Fry 1997a, b, c) such as in wheat bran, oat hulls (Yu et al 2002a), barley straw, and maize (Faulds and Williamson 1995;Faulds et al 1995a;Saulnier et al 1995a).…”