Biodegradation and detoxification of parabens, an emerging contaminant in water sources using Leucobacter aridicollis strain conR

Parabens are used in foods, cosmetics, and pharmaceuticals because they have antifungal and antibacterial activities. However, they can disrupt intracellular proteins and plasma membranes of microorganism and are also endocrine disruptors as well as carcinogens. High concentrations of parabens in water are a global concern for health. To achieve Sustainable Development Goals 3 and 6, which focus on safe drinking water and good health, respectively, removal and detoxification of these contaminants are required. This study involves biodegradation of p-hydroxybenzoic acid esters occurring in the form of Ethylparaben (EtP), Methylparaben (MeP), and Propylparaben (PrP). Degradation of 10 mg/L each of MeP, EtP, and PrP was done with Leucobacter aridicollis strain conR in nutrient broth at 30 °C, 150 rpm, for 96 h. Percentage degradation was monitored using HPLC at 24 h intervals. Environmental conditions (temperature, pH, and concentrations) were optimized to determine the best conditions for degradation. The chemical structures of the metabolites and their environmental safety were determined using GC–MS and Lemna minor (duckweed), respectively. The bacterium degraded 100% of PrP, 100% of EtP, and 92% of MeP in water contaminated with 10 mg/L each of the parabens at 96 h. The optimum conditions were 30 °C, 150 rpm, pH 7.0. The FTIR confirmed the degradation of parabens, indicated by the disappearance of the functional groups of the parabens (C-H, C-O, C = O, and O–H), the GC–MS showed the end product to be Benzoic acid, methyl ester (C8H8O2), and the toxicity studies showed that the metabolites do not have a toxic effect on the plant.