Bioremediation of a salty petrochemical wastewater containing bisphenol A by a novel indigenous Pseudomonas pseudoalcaligenes

Abstract

One novel indigenous halotolerant, Pseudomonas sp, with high potential for bisphenol A (BPA) biodegradation was isolated from an outlet of petrochemical wastewater in Iran. The optimal temperature and pH for degradation of BPA by this strain were 30 °C and 7, respectively. This strain was able to decrease COD (chemical oxygen demand) of basal salt medium containing 300 mg L⁻¹ BPA as sole carbon source and 40 g L⁻¹ NaCl from 655.2 to 109.2 mg L⁻¹ (about 83% decrease) after 36 h. The bacterium degraded 56.3 (19%), 202.43 (67%), 288.86 (96%) and 300 mg L⁻¹ (100%) BPA in basal salt medium containing 300 mg L⁻¹ BPA and 40 g L⁻¹ NaCl within 12, 18, 24 and 36 h, respectively. In addition, this strain could degrade phenol (100 mg L⁻¹) and BPA (300 mg L⁻¹) in salty petrochemical wastewater within 24 h, completely. In batch fermentation of petrochemical wastewater using this strain higher growth and phenol (100 mg L⁻¹), BPA (372 mg L⁻¹) removal within 6 h were achieved. High performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC/MS) analysis revealed several intermediates during the BPA degradation process. These intermediates were identified as 4-hydroxybenzaldehyde, 4-hydroxyacetophenone, 4-hydroxyphenylacetate, M-hydroxymandelic acid, 2-phenylpropane-1,2-diol, 2-phenyl-2-propanol and lactic acid. The possible BPA-biodegradation pathway based on the identified metabolites and in agreement with recorded pathway in KEGG database was proposed. Preliminary 16S rDNA sequence analysis and subsequent genetically characterization through comprehensive genomic analysis identified the strain as Pseudomonas pseudoalcaligenes strain YKJ.