Accessing biochemical shifts in a novel Scenedesmus strain via acetaminophen detoxification: Experiment utilizing Box-Behnken optimization and isotherm analysis

Abstract

Acetaminophen's inherent solubility and hydrophilic nature facilitate its accumulation in aquatic ecosystems. Herein, Scenedesmus dimorphus IITISM-DIX1 demonstrates efficient acetaminophen removal, concurrently serving as a substrate for lipid biosynthesis. Employing Box-Behnken design, optimization of parameters like pH, light duration and concentration of acetaminophen influencing its elimination is executed. Characterization of pre- and post-algal biomass involves FE-SEM, FTIR, and BET analysis. Kinetic and adsorption analyses reveal pseudo-first-order kinetics (R² = 0.99) and adherence to the Freundlich isotherm (R² = 0.94). FTIR spectroscopy demonstrates subtle shifts in IR bands post-sorption, indicative of biomass involvement in adsorption processes. Biodegradation and biosorption serve as the main removal pathways, facilitated by exopolysaccharides, generating by-products such as 4-aminophenol, hydroquinone, and formic acid. The Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) values obtained for the Freundlich isotherm validate it as the optimal model, indicating heterogeneous multilayered sorption with efficiency ranging from 44% to 100%. Additionally, exposure to acetaminophen-contaminated media leads to biochemical alterations in Scenedesmus dimorphus IITISM-DIX1. The findings of this study unveil the first elucidated pathway for acetaminophen degradation by any Scenedesmus species, delivering essential knowledge about microalgae-mediated acetaminophen degradation and lipid enrichment mechanisms.