Velasco Josman, Oliva Bianca, Mulinari Evandro José, Quintero Leidy Patricia, da Silva Lima Awana, Gonçalves Aline Larissa, Gonçalves Thiago Augusto, Damasio André, Squina Fabio Marcio, Ferreira Milagres Adriane Maria, Abdella Asmaa, Wilkins Mark R, Segato Fernando
Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
Department of Physics and Applied Sciences, São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil.
Biotechnol Rep (Amst). 2019 Oct 30;24:e00382. doi: 10.1016/j.btre.2019.e00382. eCollection 2019 Dec.
Xylanases decrease the xylan content in pretreated biomass releasing it from hemicellulose, thus improving the accessibility of cellulose for cellulases. In this work, an endo-β-1,4-xylanase from var. (AFUMN-GH10) was successfully expressed. The structural analysis and biochemical characterization showed this AFUMN-GH10 does not contain a carbohydrate-binding module. The enzyme retained its activity in a pH range from 4.5 to 7.0, with an optimal temperature at 60 °C. AFUMN-GH10 showed the highest activity in beechwood xylan. The mode of action of AFUMN-GH10 was investigated by hydrolysis of APTS-labeled xylohexaose, which resulted in xylotriose and xylobiose as the main products. AFUMN-GH10 released 27% of residual xylan from hydrothermally-pretreated corn stover and 14% of residual xylan from hydrothermally-pretreated sugarcane bagasse. The results showed that environmentally friendly pretreatment followed by enzymatic hydrolysis with AFUMN-GH10 in low concentration is a suitable method to remove part of residual and recalcitrant hemicellulose from biomass.
木聚糖酶可降低预处理生物质中的木聚糖含量，使其从半纤维素中释放出来，从而提高纤维素酶对纤维素的可及性。在本研究中，成功表达了一种来自[具体品种名称]的内切-β-1,4-木聚糖酶（AFUMN-GH10）。结构分析和生化特性表征表明，该AFUMN-GH10不包含碳水化合物结合模块。该酶在pH值4.5至7.0的范围内保持活性，最适温度为60℃。AFUMN-GH10在山毛榉木聚糖中表现出最高活性。通过对APTS标记的木六糖进行水解来研究AFUMN-GH10的作用方式，水解产物主要为木三糖和木二糖。AFUMN-GH10从水热预处理的玉米秸秆中释放出27%的残留木聚糖，从水热预处理的甘蔗渣中释放出14%的残留木聚糖。结果表明，采用低浓度的AFUMN-GH10进行酶解，再结合环境友好型预处理，是从生物质中去除部分残留且难降解半纤维素的合适方法。
