Endo-xylanase and β-xylosidase are the major enzymes for hemicellulose hydrolysis, which play a significant role in biomass conversion. In our previous work, the white-rot fungi Pleurotus ostreatus HAUCC 162 and Irpex lacteus CD2 were demonstrated to have strong ability in lignocellulose degradation, and the related lignin degradation enzymes were characterized. However, little was known about their hemicellulases. In this work, a novel endo-1, 4-xylanase and a β-xylosidase from Pleurotus ostreatus HAUCC 162 and Irpex lacteus CD2 were heterologously expressed and characterized. The optima of pH and temperature were 5.0 and 55 °C for rXyn162, and 6.5 and 30 °C for rXylCD2. rXyn162 showed high tolerance to metal ions such as Ca²⁺, Cr³⁺, Zn²⁺, Na⁺, and Al³⁺. The recombinant rXyn162 and rXylCD2 exhibited synergistic hydrolysis of oat spelts xylan and sodium hydroxide pretreated cornstalk (SHPC), where the degree of synergy (DS) was 2.26 for SHPC hydrolysis. MALDI-TOF-MS and HPLC analysis showed that xylooligosaccharides (XOS) with small degrees of polymerization (DP2-DP4) were the major XOS hydrolyzate during SHPC degradation by rXyn162 and rXylCD2. In addition, rXyn162 and rXylCD2 could efficiently improve the hydrolysis of SHPC by commercial cellulase. The present study suggested the potential application of rXyn162 and rXylCD2 in the field of biomass pretreatment and biofuel production.

内木聚糖酶和β-木糖苷酶是半纤维素水解的主要酶，它们在生物质转化中起重要作用。在我们以前的工作中，已证明白腐真菌平菇平菇HAUCC 162和Irpex lacteus CD2具有强大的木质纤维素降解能力，并对相关的木质素降解酶进行了表征。然而，对其半纤维素酶知之甚少。在这项工作中，异源表达和鉴定了来自平菇平菇HAUCC 162和Irpex lacteus CD2的新型内切1、4-木聚糖酶和β-木糖苷酶。对于rXyn162，最适的pH和温度分别为5.0和55°C；对于rXylCD2，最适的pH和温度为6.5和30°C。rXyn162对金属离子（例如Ca）具有很高的耐受性²⁺，Cr ³⁺，Zn 2 ⁺，Na ⁺和Al ³⁺。重组rXyn162和rXylCD2对燕麦球茎木聚糖和氢氧化钠预处理的玉米秸秆（SHPC）表现出协同水解作用，其中SHPC水解的协同作用度（DS）为2.26。MALDI-TOF-MS和HPLC分析表明，在rXyn162和rXylCD2降解SHPC期间，具有较小聚合度的木寡糖（XOS）是主要的XOS水解产物。此外，rXyn162和rXylCD2可以有效改善商业纤维素酶对SHPC的水解作用。本研究表明rXyn162和rXylCD2在生物质预处理和生物燃料生产领域的潜在应用。