Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil.
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-903, Brazil.
Int J Mol Sci. 2020 Dec 29;22(1):276. doi: 10.3390/ijms22010276.
Cellulose is the most abundant polysaccharide in lignocellulosic biomass, where it is interlinked with lignin and hemicellulose. Bioethanol can be produced from biomass. Since breaking down biomass is difficult, cellulose-active enzymes secreted by filamentous fungi play an important role in degrading recalcitrant lignocellulosic biomass. We characterized a cellobiohydrolase (Cel6A) and lytic polysaccharide monooxygenase LPMO (AA9_B) from after they were expressed in and purified. The biochemical parameters suggested that the enzymes were stable; the optimal temperature was ~60 °C. Further characterization revealed high turnover numbers ( of 147.9 s and 0.64 s, respectively). Surprisingly, when combined, Cel6A and AA9_B did not act synergistically. Cel6A and AA9_B association inhibited Cel6A activity, an outcome that needs to be further investigated. However, Cel6A or AA9_B addition boosted the enzymatic saccharification activity of a cellulase cocktail and the activity of cellulase -EGL7. Enzymatic cocktail supplementation with Cel6A or AA9_B boosted the yield of fermentable sugars from complex substrates, especially sugarcane exploded bagasse, by up to 95%. The synergism between the cellulase cocktail and AA9_B was enzyme- and substrate-specific, which suggests a specific enzymatic cocktail for each biomass by up to 95%. The synergism between the cellulase cocktail and AA9_B was enzyme- and substrate-specific, which suggests a specific enzymatic cocktail for each biomass.
纤维素是木质纤维素生物质中最丰富的多糖，它与木质素和半纤维素相互连接。生物乙醇可以从生物质中生产。由于分解生物质很困难，丝状真菌分泌的纤维素活性酶在降解顽固木质纤维素生物质方面发挥着重要作用。我们对 中的细胞外纤维素酶（Cel6A）和溶菌多糖单加氧酶 LPMO（AA9_B）进行了表达和纯化，并对其进行了表征。生化参数表明这些酶很稳定；最佳温度约为 60°C。进一步的表征揭示了高的周转数（分别为 147.9 s 和 0.64 s）。令人惊讶的是，当 Cel6A 和 AA9_B 组合时，它们并没有协同作用。Cel6A 和 AA9_B 的结合抑制了 Cel6A 的活性，这一结果需要进一步研究。然而，Cel6A 或 AA9_B 的添加都能提高纤维素酶鸡尾酒和 EGL7 的酶解活性。Cel6A 或 AA9_B 补充到酶混合物中可以提高复杂底物（尤其是甘蔗爆袋渣）的可发酵糖的产量，最高可达 95%。纤维素酶鸡尾酒和 AA9_B 之间的协同作用是酶和底物特异性的，这表明每种生物质都需要特定的酶混合物。
