Abstract PfMig188, a catabolically derepressed engineered strain of the hyper-cellulolytic fungus Penicillium funiculosum NCIM1228, was investigated for the efficacy of its secretome for biomass saccharification. An inexpensive version of media containing microcrystalline cellulose, wheat bran and soya protein was optimized for producing a high-quality secretome from the PfMig188 strain in both shake flasks and in a 20-L bioreactor. The activities of four classes of core cellulolytic enzymes required for saccharification in the PfMig188 secretome, namely, cellobiohydrolase (Avicelase activity), endoglucanase (CMCase activity), β-glucosidase (PNPGase activity) and xylanase (xylanase activity), were found to be 2.29 U/mL, 28.24 U/mL, 150 U/mL and 76 U/mL, respectively. The saccharification potential of the PfMig188 secretome was evaluated on rice straw and sugarcane bagasse pretreated with nitric acid and/or ammonium hydroxide. Saccharification performed using a 15 % (w/v) biomass load and a 3% (w/w) enzyme load released >100 g/L sugar in the hydrolysate, irrespective of the type of biomass and pre-treatment, with >80 % hydrolysis. Furthermore, the presence of lignin in nitric acid-pretreated biomass only marginally affected saccharification. Overall, the results demonstrated that the PfMig188 secretome, having relatively broad substrate specificity, is a viable and efficient substitute for T. reesei-based secretomes for diverse biomass saccharification.

中文翻译：

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工程化的 Penicillium funiculosum 产生有效的木质纤维素分解酶，用于各种预处理生物质的糖化

摘要 PfMig188 是一种超纤维素分解真菌 Penicillium funiculosum NCIM1228 的分解代谢去抑制工程菌株，研究了其分泌组对生物质糖化的功效。一种含有微晶纤维素、麦麸和大豆蛋白的廉价培养基经过优化，可在摇瓶和 20 升生物反应器中从 PfMig188 菌株中产生高质量的分泌组。发现 PfMig188 分泌组中糖化所需的四类核心纤维素分解酶的活性，即纤维二糖水解酶（Avicelase 活性）、内切葡聚糖酶（CMCase 活性）、β-葡糖苷酶（PNPGase 活性）和木聚糖酶（木聚糖酶活性）为 2.29分别为 U/mL、28.24 U/mL、150 U/mL 和 76 U/mL。在用硝酸和/或氢氧化铵预处理的稻草和甘蔗渣上评估 PfMig188 分泌组的糖化潜力。使用 15% (w/v) 生物质负载和 3% (w/w) 酶负载进行糖化，在水解产物中释放 >100 g/L 的糖，与生物质类型和预处理无关，>80%水解。此外，硝酸预处理的生物质中木质素的存在对糖化的影响很小。总的来说，结果表明 PfMig188 分泌组具有相对广泛的底物特异性，是基于里氏木霉的分泌组的可行且有效的替代品，用于多种生物质糖化。使用 15% (w/v) 生物质负载和 3% (w/w) 酶负载进行糖化，在水解产物中释放 >100 g/L 的糖，与生物质类型和预处理无关，>80%水解。此外，硝酸预处理的生物质中木质素的存在对糖化的影响很小。总体而言，结果表明 PfMig188 分泌组具有相对广泛的底物特异性，是用于多种生物质糖化的基于里氏木霉的分泌组的可行且有效的替代品。使用 15% (w/v) 生物质负载和 3% (w/w) 酶负载进行糖化，在水解产物中释放 >100 g/L 的糖，与生物质类型和预处理无关，>80%水解。此外，硝酸预处理的生物质中木质素的存在对糖化的影响很小。总体而言，结果表明 PfMig188 分泌组具有相对广泛的底物特异性，是用于多种生物质糖化的基于里氏木霉的分泌组的可行且有效的替代品。