Biodegradation of bisphenol-A in water using a novel strain of Xenophilus sp. embedded onto biochar: Elucidating the influencing factors and degradation pathway

Abstract

Bisphenol-A (BPA) is an emerging hazardous contaminant, which is ubiquitous in the environment and can cause endocrine disruptor and cancer risks. Therefore, biodegradation of BPA is an essential issue to mitigate the associated human health. In this work, a bacterial strain enables of degrading BPA, named BPA-LRH8 (identified as Xenophilus sp.), was newly isolated from activated sludge and embedded onto walnut shell biochar (WSBC) to form a bio-composite (BCM) for biodegradation of BPA in water. The Langmuir maximum adsorption capacity of BPA by WSBC was 21.7 mg g−1. The free bacteria of BPA-LRH8 showed high BPA degradation rate (∼100 %) at pH 5–11, while it was lower (＜20 %) at pH 3. The BCM eliminated all BPA (∼100 %) at pH 3–11 and 25–45 °C when the BPA level was ≤ 25 mg L−1. The spectrometry investigations suggested two possible degradation routes of BPA by Xenophilus sp. In one route, BPA (C15H16O3) was oxidized to C15H16O3, and then broken into C9H12O3 through chain scission. In another route, BPA was likely hydroxylated, oxidized, and cleaved into C9H10O4P4, which was further metabolized into CO2 and H2O in the TCA cycle. This study concluded that the novel isolated bacteria (BPA-LRH8) embedded onto WSBC is a promising and new method for the effective removal of BPA and similar hazardous substances from contaminated water under high concentrations and wide range of pH and temperature.