Impact of the Enzyme Charge on the Production and Morphological Features of Cellulose Nanofibrils

Abstract

The available research does not allow specific relationships to be established between the applied enzymatic-mechanical treatment, the degree of polymerization, and the characteristics of the cellulose nanofibrils (CNFs) produced. This work aims to establish specific relationships between the intensity of enzymatic treatment, the degree of polymerization of the cellulose, the morphology of CNFs, and the tensile strength of the CNF films. It is determined that the decrease in the degree of polymerization plays an essential role in the fibrillation processes of the cell wall to produce CNFs and that there is a linear relationship between the degree of polymerization and the length of CNFs, which is independent of the type of enzyme, enzyme charge, and intensity of the applied mechanical treatment. In addition, it is determined that the percentage of the decrease in the degree of polymerization of CNFs due to mechanical treatment is irrespective of the applied enzyme charge. Finally, it is shown that the aspect ratio is a good indicator of the efficiency of the fibrillation process, and is directly related to the mechanical properties of CNF films.

Simultaneous Production of Cellulose Nitrates and Bacterial Cellulose from Lignocellulose of Energy Crop

“…In the initial 2 h of hydrolysis, the cellulose DP decreased from 1770 to 1490, while the DC increased from 64 to 72%. The changes in the cellulose properties may be attributed to the random cleavage of β-1,4-glucosidic bonds by endoglucanase, occurring in the less organized regions of cellulose, leading to a decrease in DP and an increase in crystallinity [ 81 , 82 , 83 ].…”

Twin-screw extrusion for the production of nanocellulose-PVA gels with a high solid content

“…However, this results in a severe reduction in degree of polymerization. The CNFs are heterogeneous in width, contain a fraction of microscale fibrils and the CNF gels lack transparency (Henríquez-Gallegos et al, 2021;Tarrés et al, 2016).…”

The development of an advanced biorefinery to produce cellulosic sugars and bionanomaterials

“…These results point to the fact that particle-particle interactions and entanglement seems to be occurring easily for the conditions with low cellulose conversion (conditions EH-5-30 and EH-10-72 with cellulose conversion of 18% and 22%, respectively). Conversely, materials with higher polysaccharide depolymerization, containing a more fragmented structure, would require greater energy input to achieve a similar viscous aspect or the complete loss of the property (Henríquez-Gallegos et al, 2021). Because the viscosity gain is an incremental process, visual observation of the suspensions indicated the gelation started approximately at a shear viscosity of 4 cP for most conditions, which can be useful to define quantitatively the "gellike" aspect (data not shown).…”

“…This is because fiber fragmentation can be intensified with an increased endoglucanase loading but the endoglucanases action can vary according to its family, and it can plateau due to substrate saturation, specific catalytic activity, and composition of commercial cocktails (singlecomponent or preparation of enzymes with collaborative action) (Wang et al 2015;Nagl et al 2021). Thus, the enzyme loading is not necessarily proportional to the reduction of fiber width and length, nor to energy savings during mechanical treatment (Henríquez-Gallegos et al, 2021;Xiuyu Liu et al, 2019;Nagl et al, 2021;Wang et al, 2015). Nagl and coworkers showed that the endoglucanase causing the lowest release of sugars provided the highest degree of refining (°SR) (Nagl et al 2021).…”

“…An increase of FiberCare enzyme loading up to 10 mg.g -1 result in a pulp yield of about 95% and DP of about 440 (Wang et al 2015). Other characteristics are also dependent on reaction conditions, endoglucanase type and loading, and intensity of mechanical fibrillation, such as crystallinity index ranges of 50 -84% (Iwamoto et al, 2007;Nechyporchuk et al 2015;Berto et al 2021) and transmittance can vary 25 -90%, in which high transmittance is obtained by applying a dispersion post-treatment (Wang et al 2015;Henríquez-Gallegos et al 2021). The colloid stability in water obtained by zeta potential for enzymatic-CNF is approximately -30 to -20 mV (Espinosa et al, 2017;Pereira et al, 2021) and thermal stability is similar to the cellulose (Onset decomposition temperature of 230 o C) (Berto et al, 2021).…”