Hydrodynamic cavitation as a promising pretreatment technology to enhance the efficiency of cellulose nanocrystal production via enzymatic hydrolysis

Enzymatic hydrolysis to produce cellulose nanocrystals (CNCs) offers economical and sustainability advantages. However, since this is still an emerging technology, further improvements are needed to make the process feasible for scale-up. In our study, we propose a novel approach using hydrodynamic cavitation (HC) as a pretreatment technology to enhance the efficiency and yield of CNC production. HC treatments conducted under various scenarios induced structural modifications of the cellulose fibers that facilitated their defibrillation and subsequent enzymatic hydrolysis. Isolation through hydrolysis involved the synergistic action of specific enzymes, including xylanase and endoglucanase. Xylanase acted on the hemicellulosic fraction, breaking down the xylan structure and exposing the cellulose fibers. Subsequently, endoglucanase targeted the amorphous regions of cellulose, releasing CNCs. By integrating the HC pretreatment with enzymatic hydrolysis, we achieved remarkable results. High-yield CNCs, reaching approximately 60%, were obtained with a crystallinity index ranging from 81% to 85%. Moreover, this process demonstrated a significant reduction in total energy consumption of approximately 56%, contributing to its economic viability. Furthermore, CNCs with diverse morphologies, aspect ratios, and viscosity profiles were produced, enabling the tailoring of their properties for specific and new applications.

Automated summary

In this study, hydrodynamic cavitation (HC) was proposed as a pretreatment technology to enhance the production efficiency and yield of cellulose nanocrystals (CNCs). By integrating HC pretreatment with enzymatic hydrolysis, high-yield CNCs were obtained with reduced energy consumption. Additionally, CNCs with diverse morphologies and viscosity profiles were produced, allowing for tailored properties for specific applications.