American Association for Aerosol Research - Abstract Submission

AAAR 36th Annual Conference
October 16 - October 20, 2017
Raleigh Convention Center
Raleigh, North Carolina, USA

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Biosurfactants Produced by Cloud Micro-Organisms: Potential Impact on Cloud Droplet Formation

ANNE-MARIE DELORT, Isabelle Canet, Pascal Renard, Martine Sancelme, Laurent Deguillaume, Nolwenn Wirgot, Université Clermont Auvergne, France

     Abstract Number: 78
     Working Group: Bioaerosols

Abstract
480 microorganisms collected from 39 clouds sampled at the puy de Dôme station (alt. 1465 m, 45°46'19"N, 2°57'52"E, Massif Central, France) were isolated and identified.1 This unique collection was screened for biosurfactant (surfactants of microbial origin) production by measuring the surface tension (σ) of crude extracts consisting of the supernatants of the pure cultures by the pendant drop technique.2 41% of the tested strains are active producers (σ-1), 7% being extremely active (σ-1). The most efficient biosurfactant producers (σ-1) belong to a few bacterial genera (Pseudomonas and Xanthomonas) from the Υ-Proteobacteria phylum (78%), and yeast genera (Cryptococcus and Dioszegia) from the Basidiomycota phylum (11%). Some Bacillus strains from the Firmicutes phylum are also active but represent a very small fraction of the total population. Strains from the Actinobacteria phylum are mainly present in the group with a moderate biosurfactant production (45<σStatistical analyses showed some positive correlations between the origin of air masses and chemical composition of cloud waters3 with the presence of biosurfactant-producing microorganisms in clouds, suggesting a “biogeography” of this production.
Finally we discuss the potential impact of the production of biosurfactants by cloud microorganisms on atmospheric processes.

Acknowledgements
This work was supported by the French ANR program SONATA. The authors are very grateful to the OPGC staff for help with cloud water collection at the puy de Dôme station. wwwobs.univ-bpclermont.fr/SO/beam/index.php.

References
[1] M. Vaïtilingom, E. Attard, N. Gaiani, M. Sancelme, L. Deguillaume, A.I. Flossmann, P. Amato, A.-M. Delort, Atmos. Environ., 2012, 56, 88-100.
[2] P. Renard, I. Canet, M. Sancelme, N. Wirgot, L. Deguillaume, A.-M. Delort, Atmos. Chem. Phys., 2016, 16, 12347-12358.
[3] L. Deguillaume, T. Charbouillot, M. Joly, M.Vaïtilingom, M. Parazols, A. Marinoni, P. Amato, A.-M. Delort, V. Vinatier, A. Flossmann, N. Chaumerliac, J.-M. Pichon, S. Houdier, P. Laj, K. Sellegri, A. Colomb, M. Brigante, G. Mailhot, Atmos. Chem. Phys., 2014, 14, 1485-1506.