Characterization, optimization and kinetic study of diclofenac degradation by novel bacterial strains and their synthetic consortia
Sunil Chopra, Dharmender Kumar
Abstract
Diclofenac (2-(2-(2, 6-dichlorophenylamino) phenyl) acetic acid, DCF) is an emerging pollutant under the sub-class of pharmaceutical and personal care products (PPCPs). This study focused on the degradation of DCF with isolated microbial strains. The bacterial strains are considered a cost effective and eco-friendly approach for the degradation of such harmful compounds from the environment. Therefore, the experiments were started with isolation of the DCF degrading strains by the enrichment culture method. Finally, four bacterial strains; Enterococcus lactis strain DSD-1 (MN744331), Bacillus paranthracis strain DYD-1 (MN744332), Citrobacter portucalensis strain PPD-2 (MN744333) and Enterococcus faecium strain DKD-1 (MN744334) were isolated from wastewater samples. These strains degrade DCF and use it as the sole carbon and energy source. Optimized physical parameters such as temperature (32.65 °C), pH (6.36), agitation speed (82.93 rpm), and DCF concentration (40.53 mg/L) were reported through Design Expert® software. The microbial consortium experiments suggested that equal volume of all the strains was very effective. This common microbial consortium degraded almost 90% of DCF in 20 days. This was due to the synergistic activities of the strains. We have reported five intermediate metabolites (DF-1, DF-2, DF-3, DF-4, and DF-5) through the GC-MS. These further used to predict the metabolic pathway of DCF degradation.