First chemical insights into airborne microbial communities isolated from ambient particulate matter in the Iasi urban area, north-eastern Romania

Airborne microorganisms are important constituents of the ambient particulate matter (PM) with adverse effects on the environment and human health. Evidence for various microbial communities in ambient bulk PM from the Iasi urban area, north-eastern Romania, is unveiled by a culture-dependent approach. Chemical characteristics specific at molecular or elemental level for isolated bacteria, fungi, and yeasts are presented. MALDI-Orbitrap MS data enabled the identification of bacterial cell membrane components, with surfactin C and surfactin D cyclic lipopeptides resolved by isotopic analysis. In the isolated microorganisms the concentration of essential elements (Fe, Cu, Zn, Ni, Co, Mn, and V), and other trace- (Ca, Mg, Al, B, Rb, Sr, and Ba) and ultra-trace (Cr, Pb, Tl, Li, Cd, Bi, and U) elements were measured by the ICP-MS technique. Bacterial, fungal, and yeast isolated microorganisms seem to present high potential to be involved in U-biogeochemical cycling. The study highlights the fact that comprehensive and efficient control strategies should be implemented to improve air quality in terms of microbial burden in the interest area since most identified microorganisms are known to exert negative impact on human health.