Isolation and characterization of Aeromonas sp. TXBc10 capable of high-efficiency degradation of octylphenol polyethoxylate from tannery wastewater

Abstract

ABSTRACT Octylphenol polyethoxylate (OP n EO) is a potential endocrine-disrupting chemical. Biodegradation of OP n EO was investigated using the bacterium Aeromonas sp. TXBc10 isolated from the influent of tannery waste treatment plant in Hunan Province, China. The bacterium was capable of utilizing OP n EO as the sole source of carbon and energy while OP n EO was degraded under aerobic batch culture conditions. Microbial degradation of OP n EO was studied in batch experiments for optimization of environmental factors. The effect of initial OP n EO concentrations on the degradation was investigated between 100 and 1000 mg·L−1 and the results showed that the biodegradation process conformed to the first-order kinetic model. The optimum pH, temperature, salinity and size of inoculum for OP n EO degradation by Aeromonas sp. TXBc10 was found to be 8.0°C, 30°C, 2.5% and 2.0%, respectively. The major metabolites of OP n EO degradation were identified as short-chain octylphenol polyethoxylate without octylphenol by high-performance liquid chromatography – mass spectrometer, which indicated that sequential cleavage of single ethoxylate units to form OP n- 1EC might be the transformation mechanism of strain TXBc10. Considering that strain TXBc10 exhibits prominent advantage for biodegradation of OP n EO, it might serve as a promising candidate for in situ remediation of OP n EO and compounds with similar structure in tannery wastewater.