Determining the degradation mechanism and application potential of benzopyrene-degrading bacterium Acinetobacter XS-4 by screening

• Published in: Journal of hazardous materials 2023-08, Vol.456, p.131666-131666, Article 131666
• Main Authors: Zou, Xiaoshuang, Su, Qi, Yi, Qianwen, Guo, Ling, Chen, Diyong, Wang, Bin, Li, Yancheng, Li, Jiang
• Format: Article
• Language: English
• Subjects: Acinetobacter; Bacteria - metabolism; Benzo [a] pyrene (BaP); Benzo(a)pyrene - metabolism; Biodegradation, Environmental; Coking wastewater; Degradation pathway; Environmental Pollutants - metabolism; Immobilized microorganism; Wastewater
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.131666

In industrial wastewater treatment, organic pollutants are usually removed by in-situ microorganisms and exogenous bactericides. Benzo [a] pyrene (BaP) is a typical persistent organic pollutant and difficult to be removed. In this study, a new strain of BaP degrading bacteria Acinetobacter XS-4 was obtained and the degradation rate was optimized by response surface method. The results showed that the degradation rate of BaP was 62.73% when pH= 8, substrate concentration was 10 mg/L, temperature was 25 °C, inoculation amount was 15% and culture rate was 180 r/min. Its degradation rate was better than that of the reported degrading bacteria. XS-4 is active in the degradation of BaP. BaP is degraded into phenanthrene by 3, 4-dioxygenase (α subunit and β subunit) in pathway Ⅰ and rapidly forms aldehydes, esters and alkanes. The pathway Ⅱ is realized by the action of salicylic acid hydroxylase. When sodium alginate and polyvinyl alcohol were added to the actual coking wastewater to immobilize XS-4, the degradation rate of BaP was 72.68% after 7 days, and the removal effect was better than that of single BaP wastewater (62.36%), which has the application potential. This study provides theoretical and technical support for microbial degradation of BaP in industrial wastewater. [Display omitted] •A new strain of BaP degrading bacterium Acinetobacter XS-4 was obtained.•Among the BaP degrading bacteria, the degradation rate of XS-4 was higher.•XS-4 degrades BaP through the salicylic acid and phthalic acid pathways.•The immobilized XS-4 pellet has a good removal effect on coking wastewater.