University of Helsinki, Food and Environmental Sciences, P.O. Box 27, 00014 Helsinki, Finland.
Bioresour Technol. 2011 Oct;102(19):9096-104. doi: 10.1016/j.biortech.2011.06.059. Epub 2011 Jun 22.
The impact of xylan and glucomannan hydrolysis on cellulose hydrolysis was studied on five pretreated softwood substrates with different xylan and glucomannan contents, both varying from 0.2% to 6.9%, using mixtures of purified enzymes. The supplementation of pure cellulase mixture with non-specific endoglucanase TrCel7B and xylanase TrXyn11 enhanced the hydrolysis of all substrates, except the steam pretreated spruce, by more than 50%. The addition of endo-β-mannanase increased the overall hydrolysis yield by 20-25%, liberating significantly more glucose than theoretically present in glucomannan. When supplemented together, xylanolytic and mannanolytic enzymes acted synergistically with cellulases. Moreover, a linear correlation was observed between the hydrolysis of polysaccharides, irrespective of the composition, indicating that glucomannan and xylan form a complex network of polysaccharides around the cellulosic fibres extending throughout the lignocellulosic matrix. Both hemicellulolytic enzymes are crucial as accessory enzymes when designing efficient mixtures for the total hydrolysis of lignocellulosic substrates containing both hemicelluloses.
研究了五种不同木聚糖和葡聚糖含量（0.2%至 6.9%）的预处理软木基质中木聚糖和葡聚糖水解对纤维素水解的影响，使用了混合的纯化酶。在纯纤维素酶混合物中添加非特异性内切葡聚糖酶 TrCel7B 和木聚糖酶 TrXyn11，除了蒸汽预处理的云杉外，所有底物的水解率都提高了 50%以上。添加内切 β-甘露聚糖酶使总水解产率提高了 20-25%，释放出的葡萄糖量明显多于理论上存在于葡聚糖中的葡萄糖量。当一起补充时，木聚糖酶和甘露聚糖酶与纤维素酶协同作用。此外，还观察到无论多糖组成如何，多糖的水解之间都存在线性相关性，表明葡聚糖和木聚糖在延伸穿过木质纤维素基质的纤维素纤维周围形成了一个复杂的多糖网络。当设计含有半纤维素的木质纤维素底物的总水解的有效混合物时，这两种半纤维素酶都是必不可少的辅助酶。
