Paracetamol biodegradation coupling lipid biosynthesis in acclimated microalgae Coccomyxa subellipsoidea

Paracetamol (PAR) has received increasing concern due to its large usage, ubiquitous detection in environment and high ecotoxicology risk. This study investigated the effect of PAR on the growth and lipid production of Coccomyxa subellipsoidea, removal of PAR by C. subellipsoidea, and the metabolic difference in C. subellipsoidea after exposure to PAR. The PAR promoted C. subellipsoidea growth but the biomass increment reduced with PAR concentration increasing. Acclimation evolution could enhance removal capacity of C. subellipsoidea to PAR. Compared to wild C. subellipsoidea, the removal percentage of PAR by acclimated C. subellipsoidea increased 2.71-fold, the content and yield of lipid as well as the content of unsaturated fatty acid in acclimated C. subellipsoidea significantly increased by 1.06-, 1.13- and 1.12-fold, respectively. The metabolism fate of PAR analysis revealed that p-aminophenol was the first step degradadation product, and the molecular docking simulating suggested p-aminophenol was the most prone to undergo metabolism. Differential metabolites analysis showed that the up-regulating glutathione with 2.20-fold in C. subellipsoidea withstanded oxidative stress from PAR and actuated the PAR degradation, the up-regulating citric acid and fumarate as well as malate used as precursor of lipid biosynthesis actuated lipid accumulation. This work provides new insights for using microalgae for efficient treatment of wastewater containing pharmaceuticals contaminants (PCs) coupling high value-added products production.