Sustainable Production of Potato Pulp-derived Cellulose Nanocrystals with Enhanced Heavy Metal Adsorption and Biocompatibility: A Comparative Study with Conventional Feedstocks

Abstract

Potato pulp was demonstrated to be a superior lignocellulosic feedstock for cellulose nanocrystal (CNC) production, addressing critical limitations of conventional potato peel-derived CNCs. CNCs with 90.6% cellulose content and 73.4% crystallinity through optimized chemical processing, surpassed peel-based CNCs (70% to 75%) while requiring 33% shorter hydrolysis time. The resulting CNCs demonstrated exceptional thermal stability (315 °C vs. 290 to 300 °C for peel) and adsorption capacity for Pb²⁺ (7.15 mg/g), While recent advanced chemical treatments of potato peel (e.g., intensive esterification, phosphorylation) have reported very high adsorption capacities (e.g., ~217 mg/g for Pb²⁺) for effective drug-carrier functionality, these achievements often come at the cost of process complexity, chemical intensity, and potential impacts on biocompatibility. In contrast, the pulp-derived CNCs achieved effective heavy metal removal, promising drug loading potential through a markedly simpler and less chemically intensive standard sulfation process. This efficiency is attributed to the feedstock's inherent advantages: a significantly lower lignin content (0.65% vs. 5.2 to 20% in peel) and a high sulfate group density (zeta potential: −39.9 mV), which enhances colloidal stability and available binding sites. Cytotoxicity assays confirmed superior biocompatibility at concentrations up to 2000 µg/mL, outperforming peel-derived CNCs (typically >500 µg/mL).