Endoglucanase and accessory enzymes facilitate high yield pulp fibrillation into lignin-containing cellulosic nanofibrils

High-yield fibers, containing much of the original composition of woody biomass, includes mechanical and chemi-thermomechanical pulps. Collectively, they represent major products derived from Canadian softwoods, which are traditionally used to produce newsprint. These processes have the advantages of lower production costs and significantly lower environmental impact compared to chemical (e.g. Kraft) processes. Given the decline in the demand of newsprint and writing grades the demand for high-yield pulps has been in dramatic decline. It is therefore of pressing urgency to expand the portfolio of products that can be derived from mechanical pulps. In contrast, the markets for products using cellulose nanofibrils have been growing steadily. For uses in packaging, paperboard, nanocomposites and nanopapers. To date, most nanofibrils have been produced by defibrillating chemical pulps such as Kraft and sulfite pulps. Little work has been done on assessing the potential of fibrillating high lignin-containing, high-yield fibers. At the same time the potential of enzyme-mediated fibrillation of mechanical pulps has not received much attention to date. The little work that has been done has primarily focussed on the potential modification of chemical pulps. In the work that will be reported, lignin-containing cellulose nanofibrils (LCNF) produced from mechanical fibers were modified by enzymatic treatments followed by mechanical disintegration and sonication. Subsequently, how the selective addition of enzymes might enhance mechanical pulp fibrillation was assessed. Different combinations of enzymes including endoglucanase (EG), xylanase, mannanase and lytic polysaccharide monooxygenase (LPMO) were added to the fibers, followed by mechanical treatments.