Valorization of Cannabis sativa Residual Biomass from Industrial CBD Extraction as a Renewable Support for Candida antarctica Lipase B Immobilization and Fatty Acid Esterification

Abstract

Residual Cannabis sativa biomass from industrial CBD extraction in ethanol was evaluated as a renewable support for the immobilization of Candida antarctica lipase B (CALB) by physical adsorption, and the resulting biocatalysts were applied to the esterification of long-chain fatty acids with ethanol. Because extractives released by the untreated biomass interfered with protein quantification, three simple pretreatments were compared. Milling alone, with or without buffer washing, gave reproducible immobilization and active, reusable biocatalysts, whereas SDS washing increased protein retention but led to nearly inactive preparations, indicating that protein loading alone does not predict catalytic performance. The milling-only biocatalyst converted two industrial palm fatty acid distillate fractions with conversions comparable to those of Novozym 435, retained more than 80% of its initial conversion after five cycles, and was operated in a continuous-flow packed-bed reactor with conversions of 95% or higher at a residence time of 15 min. These results indicate that this residue is a low-cost, minimally processed support for lipase-catalyzed esterification.