两株木霉属 Xz-8 内切 1,4-β-木聚糖酶具有较高的催化效率和在酿造工业中的应用潜力。
Two family 11 xylanases from Achaetomium sp. Xz-8 with high catalytic efficiency and application potentials in the brewing industry.
机构信息
Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China.
出版信息
J Agric Food Chem. 2013 Jul 17;61(28):6880-9. doi: 10.1021/jf4001296. Epub 2013 Jul 3.
This study identified two family-11 xylanase genes (xynC81 and xynC83) in Achaetomium sp. Xz-8, a thermophilic strain from a desert area with substantial xylanase activity, and successfully expressed them in Pichia pastoris . Their deduced amino acid sequences showed the highest identity of ≤90% to known fungal xylanases and of ≤62% with each other. The purified recombinant xylanases showed optimal activities at pH 5.5 and 60-65 °C and exhibited stability over pH 5.0-10.0 and temperatures at 55 °C and below. XynC81 had high catalytic efficiency (6082 mL/s/mg), and XynC83 was favorable for xylooligosaccharide production. Under simulated mashing conditions, combination of XynC83 and a commercial β-glucanase improved the filtration rate by 34.76%, which is much better than that of Novozymes Ultraflo (20.71%). XynC81 and XynC83 had a synergistic effect on viscosity reduction (7.08%), which is comparable with that of Ultraflo (8.47%). Thus, XynC81 and XynC83 represent good candidates for application in the brewing industry.
本研究在一株嗜热真菌 Achaetomium sp. Xz-8 中鉴定出两个家族 11 木聚糖酶基因（xynC81 和 xynC83），该真菌来自沙漠地区，具有较高的木聚糖酶活性，并在毕赤酵母中成功表达。它们的推导氨基酸序列与已知真菌木聚糖酶的最高同源性≤90%，彼此之间的同源性≤62%。纯化的重组木聚糖酶在 pH5.5 和 60-65°C 下显示出最佳活性，并在 pH5.0-10.0 和 55°C 及以下的温度下表现出稳定性。XynC81 具有较高的催化效率（6082 mL/s/mg），而 XynC83 有利于生产木寡糖。在模拟糖化条件下，XynC83 与一种商业β-葡聚糖酶的组合可将过滤速度提高 34.76%，明显优于诺维信的 Ultraflo（20.71%）。XynC81 和 XynC83 对降低黏度有协同作用（7.08%），与 Ultraflo（8.47%）相当。因此，XynC81 和 XynC83 是应用于酿造工业的良好候选者。
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