TY - JOUR
T1 - Enzymatic Cleavage of Diferuloyl Cross-Links in Corn Bran Arabinoxylan by Two Bacterial Feruloyl Esterases
AU - Lin, Shang
AU - Brask, Jesper
AU - Munk, Line
AU - Holck, Jesper
AU - Krogh, Kristian B. R. M.
AU - Meyer, Anne S.
AU - Wittrup Agger, Jane
AU - Wilkens, Casper
PY - 2022
Y1 - 2022
N2 - Corn bran is an abundant coprocessing stream of corn-starch processing, rich in highly substituted, diferuloyl-cross-linked glucurono-arabinoxylan. The diferuloyl cross-links make the glucurono-arabinoxylan recalcitrant to enzymatic conversion and constitute a hindrance for designing selective enzymatic upgrading of corn glucurono-arabinoxylan. Here, we show that two bacterial feruloyl esterases, wtsFae1A and wtsFae1B, each having a carbohydrate-binding module of family 48, are capable of cleaving the ester bonds of the cross-linkages and releasing 5-5', 8-5', 8-5' benzofuran, and 8-O-4' diferulate from soluble and insoluble corn bran glucurono-arabinoxylan. All four diferulic acids were released at similar efficiency, indicating nondiscriminatory enzymatic selectivity for the esterified dimer linkages, the only exception being that wtsFae1B had a surprisingly high propensity for releasing the dimers, especially 8-5' benzofuran diferulate, indicating a potential, unique catalytic selectivity. The data provide evidence of direct enzymatic release of diferulic acids from corn bran by newly discovered feruloyl esterases, i.e., a new enzyme activity. The findings yield new insight and create new opportunities for enzymatic opening of diferuloyl cross-linkages to pave the way for upgrading of recalcitrant arabinoxylans.
AB - Corn bran is an abundant coprocessing stream of corn-starch processing, rich in highly substituted, diferuloyl-cross-linked glucurono-arabinoxylan. The diferuloyl cross-links make the glucurono-arabinoxylan recalcitrant to enzymatic conversion and constitute a hindrance for designing selective enzymatic upgrading of corn glucurono-arabinoxylan. Here, we show that two bacterial feruloyl esterases, wtsFae1A and wtsFae1B, each having a carbohydrate-binding module of family 48, are capable of cleaving the ester bonds of the cross-linkages and releasing 5-5', 8-5', 8-5' benzofuran, and 8-O-4' diferulate from soluble and insoluble corn bran glucurono-arabinoxylan. All four diferulic acids were released at similar efficiency, indicating nondiscriminatory enzymatic selectivity for the esterified dimer linkages, the only exception being that wtsFae1B had a surprisingly high propensity for releasing the dimers, especially 8-5' benzofuran diferulate, indicating a potential, unique catalytic selectivity. The data provide evidence of direct enzymatic release of diferulic acids from corn bran by newly discovered feruloyl esterases, i.e., a new enzyme activity. The findings yield new insight and create new opportunities for enzymatic opening of diferuloyl cross-linkages to pave the way for upgrading of recalcitrant arabinoxylans.
KW - Arabinoxylan
KW - Diferulic acid
KW - Feruloyl esterase
KW - Carbohydrate-binding module 48
U2 - 10.1021/acs.jafc.2c04455
DO - 10.1021/acs.jafc.2c04455
M3 - Journal article
C2 - 36205442
SN - 0021-8561
VL - 70
SP - 13349
EP - 13357
JO - Journal of Agricultural and Food Chemistry
JF - Journal of Agricultural and Food Chemistry
IS - 41
ER -