Bioremediation of Acetaminophen and Hydroxychloroquine by Kosakonia cowanii JCM 10956(T) with ecotoxicity studies

Abstract Acetaminophen and hydroxychloroquine are widely used drugs during COVID situations. Residual concentrations of acetaminophen and hydroxychloroquine have been detected in pharmaceutical industry wastewater, effluent treatment plants, and surface water. The present study was carried out on the bioremediation of acetaminophen (paracetamol) and hydroxychloroquine by using the bacterial isolate Kosakonia cowanii JCM 10956(T) (GenBank: OQ733302.1). Identification of the isolate was done using the 16S rRNA sequencing technique. The LC50 values for bacteria were determined for acetaminophen and hydroxychloroquine as 2186.70 and 1735.13 ppm, respectively. Isolate was found to degrade acetaminophen (1500 ppm) into hydroquinone after five days of incubation with an 81% biodegradation rate. Hydroxychloroquine (1000 ppm) was found to be degraded into oxalic acid with 7-chloroquinoline-4-amine and 4-aminoquinoline-7-ol as intermediates. After 15 days of incubation, 60% of hydroxychloroquine was found to be degraded. Acetaminophen and hydroxychloroquine biodegradation followed a first-order kinetic model with a rate constant of 0.339 d− 1 and 0.0618 d− 1, respectively. Half-lives for acetaminophen and hydroxychloroquine were found to be 2.05 and 11.2 days, respectively. Based on the analytical techniques of UV-visible spectra, HPLC, mass spectra, and proton nuclear magnetic spectroscopy (1H NMR) studies, biodegradative metabolites were identified. Ecotoxicological testing of the parent drug and degradative product was done using algal inhibition and shrimp lethality assays. The biodegradative product of acetaminophen, hydroquinone, has more algal toxicity and less toxicity against shrimp as compared to the parent drug. Whereas for the hydroxychloroquine biodegradative product, oxalic acid has less algal toxicity and more toxicity against shrimp compared to the parent drug. Industrial applications of hydroquinone and the metal leaching role of oxalic acid will give new insight into the bioconversion of expired paracetamol and hydroxychloroquine into value-added products.