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Biodegradation of Phenol and Catechol in Cloud Water: Comparison to Chemical Oxidation in the Atmospheric Multiphase System
Saly Jaber, Audrey Lallement, Martine Sancelme, Martin Leremboure, Gilles Mailhot, Brabara Ervens, ANNE-MARIE DELORT, ICCF, CNRS, Université Clermont Auvergne
Abstract Number: 74
Working Group: Bioaerosols
Abstract
Among monocyclic aromatics in the atmosphere, phenol is of particular interest for air quality as it is considered one of the main pollutants listed by the US Environmental Protection Agency (US EPA list) since it represents a risk for humans and the environmental biota. Using GCxGC-HRMS, we detected and quantified phenol among 100 semi-volatile compounds in cloud samples collected at the puy de Dôme station (France)[1]. We investigated the potential biodegradation of phenol and catechol in clouds using two strategies [2]: 1) a metatranscriptomic analysis showed in-cloud activity of microorganisms. We detected transcripts of genes coding for phenol monooxygenases (and phenol hydroxylases) and catechol 1,2-dioxygenases. 2) 145 bacterial strains isolated from cloud water were screened for their phenol degradation capabilities, 93% of them (mainly Pseudomonas and Rhodococcus strains) were positive. These findings highlighted the possibility of phenol degradation by microorganisms in cloud water.
In our recent study [3], we measured the biodegradation rates of phenol and catechol, by one of the most active strains selected during our previous screening in clouds (Rhodococcus enclensis). For catechol, biodegradation is about 10 times faster than for phenol. The experimentally-derived biodegradation rates are included in a multiphase box model to compare the chemical loss rates of phenol and catechol in the atmospheric gas and cloud aqueous phases to their biodegradation rate in the aqueous phase only. Degradation rates in the aqueous phase by chemical and biological processes for both compounds are predicted to be similar to each other. During day-time, catechol biodegradation rates even exceed the chemical aqueous phase loss and contribute to ~20% to the total catechol transformation rate in the atmospheric multiphase system. Our results suggest that atmospheric multiphase models may be incomplete for soluble organics as biodegradation may represent an unrecognized efficient loss of such organics in cloud water.
Financial support.
Research has been supported by a school grant to the first author from the Walid Joumblatt Foundation for University Studies (WJF), Beirut, Lebanon, and the French National Research Agency (ANR) (grant nos. ANR-17-MPGA-0013and ANR-13-BS06-004-01).
References
[1] A.T. Lebedev, O.V. Polyakova, D. M. Mazur, V.B. Artaev, I. Canet, A. Lallement, M. Vaïtilingom, L. Deguillaume, A.-M. Delort. Environnmental Pollution, 241, (2018) 616-625.
[2] A. Lallement, L. Besaury, E. Texier, M. Sancelme, P. Amato, V. Vinatier, I. Canet, O.V. Polyakova, V.B. Artaev A.T. Lebedev , L. Deguillaume, G. Mailhot and A.-M. Delort. Biogeoscience, 15 (2018) 5733-5744.
[3] S. Jaber, A. Lallement, M. Sancelme, M. Leremboure, G. Mailhot, B. Ervens, and A.-M. Delort. Atmos. Chem. Phys., 20, (2020), 4987–4997, 2020, https://doi.org/10.5194/acp-20-4987-2021–11.