Benzo[A]Pyrene Biodegradation by Multiple and Individual Mesophilic Bacteria under Axenic Conditions and in Soil Samples

Alexis Nzila*, Musa M. Musa, Emmanuel Afuecheta, Assad Al-Thukair, Saravanan Sankaran, Lei Xiang, Qing X. Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


To date, only a handful of bacterial strains that can independently degrade and utilize benzo[a]pyrene (BaP) as the sole carbon source has been isolated and characterized. Here, three new bacterial strains—JBZ1A, JBZ2B, and JBZ5E—were isolated from contaminated soil and, using 16S rRNA sequencing, were identified as Brad rhizobium japonicum, Micrococcus luteus, and Bacillus cereus, respectively. The growth ability of each individual strain and a consortium of all strains in the presence of BaP (4–400 µmol·L−1, pH 7, 37 °C) was identified by the doubling time (dt). The results illustrate that dt decreased with increasing BaP concentrations for individual strains and the consortium. The optimum growth conditions of the consortium were 37 °C, 0.5% NaCl (w/v), and pH 7. Under these conditions, the degradation rate was 1.06 µmol·L−1·day−1, whereas that of individual strains ranged from 0.9 to 0.38 µmol·L−1·day−1. B. cereus had the strongest contribution to the consortium’s activity, with a degradation rate of 0.9 µmol·L−1·day−1. The consortium could also remove BaP spiked with soil but at a lower rate (0.01 µmol L−−1). High-performance liquid chromatography–high-resolution tandem mass spectrometry permitted the detection of the metabolites of these strains, and a biodegradation pathway is proposed.

Original languageEnglish
Article number1855
JournalInternational Journal of Environmental Research and Public Health
Issue number3
StatePublished - Feb 2023

Bibliographical note

Funding Information:
Alexis Nzila and Musa M. Musa acknowledge the financial support provided by the King Fahd University of Petroleum and Minerals and the Ministry of Higher Education of Saudi Arabia through the Deanship of Scientific Research under project numbers “IN171022” and “LS002505”, respectively.

Publisher Copyright:
© 2023 by the authors.


  • bacterial consortia
  • bioremediation
  • chromatography
  • mass spectrometry
  • polyaromatic hydrocarbons

ASJC Scopus subject areas

  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis


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