Production of High Solid Nanocellulose by Enzyme-Aided Fibrillation Coupled with Mild Mechanical Treatment

Abstract

Plant-based cellulosic materials are intriguing building blocks for functional materials, and sustainable nanocellulose production strategies have been intensively explored. Most of the existing strategies, however, suffer from the fact that highly energy-intensive fiber fibrillation yields a nanocellulose gel containing more than 95% water. We showcase a high throughput production method for nanocellulose, which primarily exploits the efficiency of enzymatic actions to disintegrate pulp fibers at a notable high solid content (25 wt %) without the need for high shear disintegration. The main enzyme activity exploited was cellobiohydrolase with the aid of endoglucanase. A pastelike fibril network is postulated to be formed through a peeling-type of reaction induced by the combined action of the enzymes used and fiber−fiber friction, with a yield of approximately 85%. Based on scanning electron microscopy and atomic force microscopy analyses, the formed nanocellulose can be classified as microfibrillated cellulose (i.e., cellulose microfibrils). Solid-state NMR and X-ray diffraction investigations revealed that the fibril morphology remained mostly intact. Our intriguing finding of a fraction with nanosized rodlike cellulose particles shows the power of enzymes in nanocellulose production. Our approach to producing nanocellulose at a high solid content in a much less energy-intensive manner puts forward the sustainable production of nanocellulose.

Rheological behavior of high consistency enzymatically fibrillated cellulose suspensions

“…These enzyme dosage levels have been selected based on our prior experience with the HefCel process, where all three levels lie within the operational window of the process. Further details concerning the HefCel process have been reported elsewhere (Pere et al 2020).…”

Immobilized cellulose nanospheres in lateral flow immunoassay enable rapid nucleocapsid antigen-based diagnosis of SARS-CoV-2 from salivary samples

“…Cellulose nanofibrils (CNF) (2.4 wt%) were prepared from bleached Kraft birch pulp fibers by using a microfluidizer (M110P fluidizer, Microfluidics Corp.) equipped with 200μm and 100-μm chambers operated at 2000 bar using six passes. High-consistency enzymatic fibrillated cellulose (HefCel) (19-23 wt%) and nanopaper (CNF films) were provided by VTT Technical Research Centre of Finland 30,31 . Microcrystalline cellulose (Avicel), dimethyl sulfoxide (DMSO) (≥99.9 %), and calcium carbonate (CaCO3) precipitated for analysis (EMSURE® Reag.…”

Emerging green routes to nanocellulose

“…57 "HefCel" stands for high-consistency enzymatic fibrillation technology developed at VTT Technical Research Centre of Finland, in which cellulose fibrils are produced at high consistency (20-40%) by stirring concen-trated cellulose pulp (20-40%) in the presence of a tailored cellulase enzyme mixture , resulting in 90% yield in fibrillated cellulose. 58 The low water content, furthermore, lowers the cost of drying.…”