Selig Michael J, Thygesen Lisbeth G, Felby Claus, Master Emma R
IGN, Faculty of Science, University of Copenhagen, Rolighedsvej 23, 1958, Frederiksberg, Denmark,
Biotechnol Lett. 2015 Mar;37(3):633-41. doi: 10.1007/s10529-014-1705-0. Epub 2014 Oct 22.
The presence of xylan is a detriment to the enzymatic saccharification of cellulose in lignocelluloses. The inhibition of the processive cellobiohydrolase Cel7A by soluble wheat arabinoxylan is shown here to increase by 50% following enzymatic treatment with a commercially-purified α-L-arabinofuranosidase. The enhanced inhibitory effect was shown by T2 relaxation time measurements via low field NMR to coincide with an increasing degree of constraint put on the water in xylan solutions. Furthermore, quartz crystal micro-balance with dissipation experiments showed that α-L-arabinofuranosidase treatment considerably increased the rate and rigidity of arabinoxylan mass association with cellulose. These data also suggest significant xylan-xylan adlayer formation occurs following initial binding of debranched arabinoxylan. From this, we speculate the inhibitory effects of xylan to cellulases may result from reduced enzymatic access via the dense association of xylan with cellulose.
木聚糖的存在不利于木质纤维素中纤维素的酶促糖化。本文表明，用商业纯化的α-L-阿拉伯呋喃糖苷酶进行酶处理后，可溶性小麦阿拉伯木聚糖对连续纤维二糖水解酶Cel7A的抑制作用增加了50%。通过低场核磁共振测量T2弛豫时间表明，增强的抑制作用与木聚糖溶液中水受到的约束程度增加相吻合。此外，石英晶体微天平与耗散实验表明，α-L-阿拉伯呋喃糖苷酶处理显著提高了阿拉伯木聚糖与纤维素质量结合的速率和刚性。这些数据还表明，去支链阿拉伯木聚糖初始结合后会形成大量木聚糖-木聚糖吸附层。由此，我们推测木聚糖对纤维素酶的抑制作用可能是由于木聚糖与纤维素的紧密结合导致酶的可及性降低。
