Characterization and biodegradation of paracetamol by Bacillus pumilus strain PYP2

Abstract

As we know the recent pandemic, coronavirus disease (COVID-19) due to SARS CoV-2 virus has led to an increase in the consumption of various drugs as medicines by the patients. Paracetamol (acetaminophen, APAP) act as an emerging contaminant classified among the class pharmaceutical and personal care pollutant (PPCP) and is detected in wastewater and sewage systems. The enrichment culture approach was used for the isolation APAP-degrading bacterium wastewater sample. Microscopic examination, biochemical and 16S rRNA sequence analysis showed that the isolate PYP-2 belongs to the Bacillus pumilus strain. Shake flask and batch culture degradation studies have shown that the strain can degrade APAP. Further, the response surface methodology (RSM) plot was used to know the best physical condition for biodegradation by optimization study. The optimum pH of 5.0, temperature of 30 °C, agitation speed of 146 rpm, and APAP 267 mg/L concentration were reported for PYP-2-based degradation. Bacterial biomass kinetic analysis was performed at the best physical condition, and the results showed that the specific growth rate (µ) was 713 mg/L. Oxalic acid, 2-isopropyl-5-methyl cyclohexanone, and phenothiazine were the intermediates of the APAP degradation pathway detected by the GC-MS chromatogram peaks. Therefore, this research has shown that Bacillus pumilus strain PYP-2 has the metabolic capacity to biodegrade APAP, providing new tools for bioremediation.