The present study demonstrates that Sporisorium reilianum, a phytopathogenic fungus of corn, produces intracellular xylanolytic activity during submerged fermentation. Production reached its highest levels in a medium containing glucose, corn hemicellulose and yeast extract. An intracellular xylanase was purified by a process that included precipitation with ammonium sulfate, ion exchange chromatography and gel filtration. Optimal pH and temperature values were 5.0 and 60 °C, respectively. The enzyme showed activity through a broad pH range. The molecular weights of pure xylanase were 36 and 37 kDa, determined by SDS PAGE and gel filtration, respectively. K_m and V_max were 0.160 mg/mL and 1.564 μmol/min/mg, respectively, on a substrate of birchwood xylan. SDS, EDTA, β-Mercaptoethanol, Tween 80, Triton and Mn²⁺ and Ca²⁺ strongly inhibited activity. The purified enzyme hydrolyzed xylan, releasing xylotriose and xylobiose. Sequence protein analysis showed 95% similarity with the theoretical protein encoded by the sr14403 gene of S. reilianum, which encodes a putative endo-β-1,4-xylanase. The enzyme is an isoform of the extracellular xylanase SRXL1 of this basidiomycete.

本研究表明玉米芽孢杆菌（Spororsorium reilianum），一种植物致病性真菌，在深层发酵过程中产生胞内木聚糖分解活性。在含有葡萄糖，玉米半纤维素和酵母提取物的培养基中，产量达到最高水平。细胞内木聚糖酶通过包括硫酸铵沉淀，离子交换色谱和凝胶过滤的方法纯化。最佳pH和温度值分别为5.0和60°C。该酶在广泛的pH范围内均显示出活性。通过SDS PAGE和凝胶过滤分别测得纯木聚糖酶的分子量为36和37 kDa。K _m和V _max在桦木木聚糖上的底物分别为0.160 mg / mL和1.564μmol/ min / mg。SDS，EDTA，β-巯基乙醇，吐温80，Triton和Mn ²⁺和Ca ²⁺强烈抑制活性。纯化的酶水解木聚糖，释放出木三糖和木糖。序列的蛋白质分析表明95％的相似性与由编码的理论蛋白sr14403的基因S.黑穗病菌，其编码推定的内切β-1,4-木聚糖酶。该酶是该担子菌的细胞外木聚糖酶SRXL1的同工型。