The development of process engineering approaches to integrate the production of biofuels and high value-added biobased products, such as enzymes and nanocellulose, is crucial to improve the financial performance and sustainability of lignocellulosic biomass biorefineries. Here, the feasibility of applying enzymes produced on-site to obtain nanocellulose was evaluated using eucalyptus cellulose pulp as a model feedstock. A systematic analysis of the structural properties of the nanomaterials obtained after hydrolysis using a cellulolytic enzymatic complex with high endoglucanase specific activity (17.09 IU/mg_protein), produced by Aspergillus niger, followed by sonication, revealed that longer ball milling pretreatment and reaction times favored extraction of the cellulose nanocrystals (CNCs). The highest yield (24.6%) of CNCs was achieved using 96 h of enzymatic hydrolysis of the ball-milled cellulose pulp, followed by sonication for 5 min. The CNCs presented approximate lengths of 294.0 nm and diameters of 24.0 nm, and the crystallinity index increased from 57.5% to 78.3%, compared to the cellulose pulp that was only ball milled. These findings demonstrated that nanocelluloses could be successfully extracted using on-site produced enzymes and that the sustainable integrated process reported here could contribute to the development of the nascent biobased economy.

中文翻译：

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未来生物炼制厂中的纳米纤维素生产：使用量身定制的酶的综合方法

整合生物燃料和酶和纳米纤维素等高附加值生物基产品生产的过程工程方法的开发，对于改善木质纤维素生物质生物精炼厂的财务绩效和可持续性至关重要。在这里，使用桉树纤维素纸浆作为模型原料，评估了应用现场产生的酶以获得纳米纤维素的可行性。用黑曲霉生产的具有高内切葡聚糖酶比活性（17.09 IU / mg_蛋白）的纤维素分解酶复合物水解后获得的纳米材料的结构特性的系统分析，然后进行超声处理，表明更长的球磨预处理和反应时间有利于纤维素纳米晶体（CNCs）的提取。使用球磨过的纤维素纸浆进行96小时的酶水解，然后超声处理5分钟，可以实现CNC的最高收率（24.6％）。与仅球磨的纤维素纸浆相比，CNC显示出大约294.0 nm的长度和24.0 nm的直径，并且结晶度指数从57.5％增加到78.3％。这些发现表明，可以使用现场产生的酶成功地提取纳米纤维素，并且这里报道的可持续整合过程可以促进新生的生物基经济的发展。