Research in the last decade showed that living microorganisms are present in cloud water, snow and bio-aerosols. Physico-chemicalproperties of aerosols strongly depend on both their origin and transformations which they undergo throughout their atmospheric transport. Aerosol particles can act as cloud condensation nuclei (CCN) in cloud droplets formation. CCN Physico-chemical properties will control properties of formed clouds such as their reflectivity (optical properties) and their lifetime (precipitation capability). Microoganisms, as bioaerosols, could be thus be involved in the microphysics of clouds [Delort 2010; Després 2012].
Atmospheric microorganisms are able to degrade effectively Volatile Organic Compounds (VOCs) present in atmospheric waters. Several studies have shown that they bio-transform methanol, formaldehyde, dicarboxylic acids. In addition to these most frequent VOCs various classes of saccharides have been reported as important constituents of ambient atmospheric aerosols. Sugars are well known as substrates for microorganisms; they represent the main source of carbon and energy for many of them. Glucose was found the most frequent saccharide in atmospheric waters.
Microorganisms are able to synthesize higher molecular mass exopolymeric substances (EPS) using various substrates present in the atmosphere. EPS can protect microorganisms against various environmental stresses and contribute to microorganism survivals in the atmosphere, and particularly in clouds. The aim of this NMR structural study was the identification of EPS produced by Bacillus sp. 3B6, a bacterium isolated from cloud water, during its incubation on glucose. A discussion will be given about the potential implication of these results for atmospheric environment.
References:
Delort, A.-M. et al. Atmospheric Research 98 (2010) 249
Després, V.R. et al. Tellus B 2012, 64
Acknowledgments:This work was supported by the VEGA 2/0007/13, APVV 0125/11 and the project implementation: Centre of Excellence for Glycomics, ITMS 26240120031, supported by the Research & Development Operational Programme funded by the ERDF.
