Comparative analysis of physical and functional properties of cellulose nanofibers isolated from alkaline pre-treated wheat straw in optimized hydrochloric acid and enzymatic processes

Twomethods, HCl and enzymatic treatments, were evaluated for diversification of morphological and functional properties of cellulose nanofibers (CNF) from two- stage-alkaline pre-treated wheat straw (WS). The extraction conditions were optimized by a central composite designed experimental approach varying time (4-8 h) and temperature (80-120 degrees C) for the HCl-based treatment and time (4-8 h), and FiberCare dosage (50-100 endo-1,4-beta-glucanase unit/g) and Viscozyme (10-20 fungal beta-glucanase units/g) for the enzyme-based treatment. The CNF yields, morphological (polydispersity index (PdI), length and diameter), and functional (crystallinity and thermal degradation) properties were compared. The CNF produced by the HCl (HCN) and enzymatically (ECN) attained diameters similar to 17 nm had PdI, length, and crystallinity of 0.53, 514 nm & 70%, and 0.92, 1.0 mu m & 48%, respectively. Thus, the HCN morphology suits homogenous nano-applications, whereas that of the ECN, would suit heterogenous nano-applications. The HCN and ECN yields were similar (similar to 20%) with optimal production time of 7.41 and 4.64 h, respectively. Both the HCN & ECN can be classified as thermally stable nanocolloids with maximum thermal degradation temperatures of similar to 380 degrees C and Zeta potential similar to-16mV. The two CNF production methods have potential synergetic effects on CNF production, morphological, and functional properties. (C) 2021 Elsevier B.V. All rights reserved.