Microbial degradation of acetylsalicylic acid and ibuprofen

Abstract

Acetylsalicylic acid (ASA), a salicylate and Ibuprofen, a propionic acid derivative are prototypical nonsteroidal anti-inflammatory agent (NSAIA) with analgesic and antipyretic properties. The presence of low levels of these drugs have been detected in many countries around the globe in sewage treatment plant (STP) effluents, surface waters, groundwater, seawaters, and some drinking water sources. The fate of these pharmaceuticals in the water cycle imposes a threat and growing concern for the future reuse of treated water. Various Physico-chemical treatment processes used for the removal of pharmaceuticals shows inability to completely mineralize these drugs. Biological treatment of contaminated water is a core technology in most of the sanitation systems and a viable options for the removal these contaminants from aqueous system. In the present study biodegradation of ASA and Ibuprofen at low concentration was investigated. Micrococcus Luteus, Pseudomonas fluorescens, Sphingomonas paucimobilis were used to determine if the selected drugs were biodegradable. In addition to selected microorganisms three microbial strains were isolated from drug contaminated sites and evaluated for their potential to degrade ASA and Ibuprofen. Toxicity analysis showed that selected microorganisms can withstand moderate concentrations of ASA and Ibuprofen. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for tested microorganism was above 80 mg/L and >150-200 mg/L, respectively. This investigation also examines the influence and optimization of various process parameters for their optimal performance such as substrate concentration, broth pH and incubation temperature. Batch degradation experiments for the removal of ASA and Ibuprofen from the aqueous solution were formed using Box-Behnken response surface design for selected microorganisms and influence of process variables on percentage of degradation was analyzed using Response Surface Methodology. The isolated bacterial strains were identified as of Bacillus species (Bacillus Subtilis, Bacillus Sonorensis and Paenibacillus lautus).