Abstract Increased demand for biofuels promotes the search for new biomass-degrading fungi. Acremonium strictum is an environmentally widespread filamentous fungi found on plant debris; that secretes lignocellulose-degrading enzymes. A recently isolated A. strictum strain, AAJ6; native to the Brazilian Cerrado biome was evaluated for its capacity to degrade lignocellulosic substrates. In this study, whole-genome sequencing of AAJ6 was performed and 775 CAZy domains were identified which correlated to those of A. strictum strain DS1bioAY4a and other lignocellulolytic fungi; suggesting AAJ6 is a high CAZyme producer. We expressed the glycoside hydrolase families GH74 and GH3 from plasmid or genome-integrated to evaluate the ethanol production from cellulosic substrates in Brazilian industrial Saccharomyces cerevisiae strains (PE-2 and SA-1) evolved for thermotolerance (AMY12 and AMY35). Those expressing the genome-integrated enzymes showed the highest β-glucosidase activity and growth in medium with cellobiose at 40°C. The strain AGY005 (integrated cassettes) showed 19, 23 and 46% higher ethanol production in SHF, pSSF (partial hydrolysis SSF) and SSF processes, respectively, using Avicel, and ∼50% more ethanol using pre-treated sugarcane bagasse, compared to the strain with a plasmid-based expression. These results indicate the improved performance of thermotolerant industrial strains with genome-integrated CAZymes in the SSF process for 2G ethanol.

中文翻译：

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从巴西 Cerrado 生物群落中分离的 Acremonium strictum AAJ6 菌株的基因组序列和用于乙醇生产的耐热工业酵母中的 CAZymes 表达

摘要 对生物燃料需求的增加促进了对新的生物质降解真菌的寻找。Acremonium strictum 是一种在植物残骸上发现的环境广泛的丝状真菌；分泌木质纤维素降解酶。最近分离的 A.strictum 菌株，AAJ6；对原产于巴西塞拉多生物群落的木质纤维素底物进行降解的能力进行了评估。在这项研究中，对 AAJ6 进行了全基因组测序，并鉴定了 775 个与 A.strictum 菌株 DS1bioAY4a 和其他木质纤维素分解真菌相关的 CAZy 结构域；表明 AAJ6 是高 CAZyme 生产者。我们表达了来自质粒或基因组整合的糖苷水解酶家族 GH74 和 GH3，以评估从耐热性进化的巴西工业酿酒酵母菌株（PE-2 和 SA-1）（AMY12 和 AMY35）中纤维素底物的乙醇生产。表达基因组整合酶的那些在 40°C 的纤维二糖培养基中表现出最高的 β-葡萄糖苷酶活性和生长。与使用 Avicel 的 SHF、pSSF（部分水解 SSF）和 SSF 工艺相比，菌株 AGY005（集成盒）的乙醇产量分别高出 19%、23% 和 46%，而使用预处理甘蔗渣的乙醇产量比使用预处理的甘蔗渣高出约 50%。具有基于质粒表达的菌株。这些结果表明，在 2G 乙醇的 SSF 过程中，具有基因组整合 CAZymes 的耐热工业菌株的性能得到改善。