Harnessing the potential of Alcaligenes faecalis for optimum biodegradation of norfloxacin spiked wastewater using response surface methodology

The use of antibiotics is increasing and they enter water untreated. These antibiotics tendency to bioaccumulate and contribute to bacterial resistance. This study is designed to explore and optimize the potential of resistant bacteria for the treatment of norfloxacin (NOR) antibiotic spiked wastewater. The Alcaligenes faecalis ABR-14 was isolated from wastewater and sludge samples and was identified using 16S rRNA sequencing (Macrogen Inc. Geumchen-gu, South Korea). The 1515 bp was submitted in NCBI Genbank and the accession number of ‘PV364597.1’ was obtained. The results demonstrated that Alcaligenes faecalis ABR-14 efficiently broke down NOR reaching 96% degradation at 100 mg/L in 10 days under ideal circumstances such as 35 °C, pH 6.5, sodium acetate, NH4Cl and 105 CFU/mL. Two significate parameters (pH and Nitrogen (N) source), one less-significant parameter (inoculum density) and 3 non-significant parameters (antibiotic concentration, temperature and Carbon (C) source) based on Central Composite Design (CCD) and Response Surface Methodology (RSM) were revealed. The Hanes plot gives straight line, where R2 is 0.99, Vmax = 200.21, Km = 133.4. The plot between experimental and predicted values represent the best fit of the values based on straightness (R2 = 0.91). ANOVA for CCD present the p value below 0.05 which represents the significance and critically important factors. This study is among the first highlights the potential application of Alcaligenes faecalis ABR-14 for norfloxacin biodegradation. The generation of non-toxic metabolites makes this eco-friendly and sustainable. The abilities of such resistant microbes can be utilized in future to develop NOR contaminated wastewater treatment plant.