Effect of light on the transformation of BDE-47 by living and autoclaved cultures of Microcystis flos-aquae and Chlorella vulgaris

Annie Chalifour, Wing Yee Chin, Pui Ying Leung, Siu Gin Cheung, Nora Fung Yee Tam

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Polybrominated diphenyl ethers (PBDEs) are ubiquitous and toxic contaminants found in high concentrations in watercourses, and are not well removed by conventional wastewater treatment facilities. This study aimed to evaluate the removal and transformation of BDE-47, one of the environmentally predominant PBDE congener, by a green alga (Chlorella vulgaris) and a cyanobacterium (Microcystis flos-aquae) under different light conditions. Living and autoclaved cultures were exposed to BDE-47 at a concentration of 10 μg L−1 for 7 days. Both species removed >90% of BDE-47 very shortly after spiking. Light intensity affected the transformation of BDE-47 in living cultures of both species, since 5 to 11 times more debromination products were measured at a light intensity of 100 μmol photons m−2 s−1 than at 20 μmol photons m−2 s−1. Living cultures of M. flos-aquae transformed BDE-47 at a rate of 0.22 day−1 while no transformation was observed in the respective autoclaved cultures. On the contrary, both living and autoclaved cultures of C. vulgaris had similar BDE-47 transformation rates of 0.05–0.06 day−1. Debromination of BDE-47 was a predominant transformation pathway in cultures of C. vulgaris, with two times higher BDE-28 concentrations measured than in M. flos-aquae, while hydroxylation was more dominant with the cyanobacterium. Most BDE-47 and its debromination product BDE-28 were found on the cell surface of both species. These results reveal that different transformation mechanisms were involved in C. vulgaris and M. flos-aquae cultures and confirm the importance of species selection for the removal of PBDEs from contaminated environments. • Higher light intensity induce higher transformation rate of BDE-47 in cultures. • The transformation rate in M. flos-aquae is 4 times higher than in C. vulgaris. • Living and autoclaved cultures of C. vulgaris have similar transformation rates. • Transformation products differ between the cyanobacterium and the green alga. • The transformation is most likely taking place on the outer cell wall.

Original languageEnglish
Pages (from-to)140-148
Number of pages9
Publication statusPublished - Oct 2019
Externally publishedYes


  • Biotransformation
  • Cyanobacteria
  • Flame retardant
  • Microalgae
  • PBDE
  • Removal


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