Nanofibrillated Cellulose Extracted by Enzymatic Hydrolysis Followed by Mechanical Fibrillation

ABSTRACT

In a comparison with certain one-step processes, enzymatic hydrolysis followed by mechanical defibrillation may avoid the use of nonrenewable resources, mitigate the generation of toxic effluents, and reduce the energy consumption related to a single mechanical process. In the present study, bleached and unbleached hardwood pulps were employed as raw materials for producing nanofibrillated cellulose (CNF) using a two-step process, in which a cellulase enzyme was inoculated to act as a pretreatment for a subsequent grinding process. The obtained CNF reached high crystallinity indexes (above 70%) and high thermal stability (degradation onset temperatures around 200°C). Increases in enzyme concentration yielded decreases in diameter and increases in both thermal stability and crystallinity index. These findings indicated that the enzymatic hydrolysis used as a pretreatment to a further grinding process can allow the production of valuable CNF-based products.

摘要

与某些一步法工艺相比, 酶水解后机械除颤可避免使用不可再生资源, 减少有毒废水的产生, 并降低与单一机械工艺相关的能耗. 本研究采用漂白和未漂白阔叶木浆作为原料, 采用两步法生产纳米纤维化纤维素 (CNF), 其中接种纤维素酶作为后续研磨过程的预处理. 获得的CNF达到高结晶指数 (70%以上) 和高热稳定性 (降解起始温度约为200°C) . 酶浓度的增加导致直径减小, 热稳定性和结晶度指数增加. 这些发现表明, 酶水解作为进一步研磨过程的预处理, 可以生产有价值的CNF基产品.

KEYWORDS:

• Nanocellulose
• biological pretreatment
• cellulase
• eucalyptus

关键词:

• 纳米纤维素
• 生物预处理
• 纤维素酶
• 桉树

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Coordination for the Improvement of Higher Education—CAPES (Financing Code 001) and National Council for Scientific and Technological Development—CNPq (Financing Code 301758/2019-0).