Applied Microbiology and Biotechnology

, Volume 97, Issue 14, pp 6561–6570 | Cite as

Temporal variability and effect of environmental variables on airborne bacterial communities in an urban area of Northern Italy

  • Valentina Bertolini
  • Isabella Gandolfi
  • Roberto Ambrosini
  • Giuseppina Bestetti
  • Elena Innocente
  • Giancarlo Rampazzo
  • Andrea Franzetti
Environmental biotechnology


Despite airborne microorganisms representing a relevant fraction of atmospheric suspended particles, only a small amount of information is currently available on their abundance and diversity and very few studies have investigated the environmental factors influencing the structure of airborne bacterial communities. In this work, we used quantitative PCR and Illumina technology to provide a thorough description of airborne bacterial communities in the urban area of Milan (Italy). Forty samples were collected in 10-day sampling sessions, with one session per season. The mean bacterial abundance was about 104 ribosomal operons per m3 of air and was lower in winter than in the other seasons. Communities were dominated by Actinobacteridae, Clostridiales, Sphingobacteriales and few proteobacterial orders (Burkholderiales, Rhizobiales, Sphingomonadales and Pseudomonadales). Chloroplasts were abundant in all samples. A higher abundance of Actinobacteridae, which are typical soil-inhabiting bacteria, and a lower abundance of chloroplasts in samples collected on cold days were observed. The variation in community composition observed within seasons was comparable to that observed between seasons, thus suggesting that airborne bacterial communities show large temporal variability, even between consecutive days. The structure of airborne bacterial communities therefore suggests that soil and plants are the sources which contribute most to the airborne communities of Milan atmosphere, but the structure of the bacterial community seems to depend mainly on the source of bacteria that predominates in a given period of time.


16S rRNA Airborne bacteria Community structure Illumina sequencing Multivariate regression trees 



This work was partially supported by Cariplo Foundation (Milan, Italy) in the frame of the project TOSCA (Toxicity of particulate matter and molecular markers of risk). The authors thank Rocco Piazza and Alessandra Pirola for the DNA sequencing and bioinformatics support.

Supplementary material

253_2012_4450_MOESM1_ESM.pdf (601 kb)
ESM 1 (PDF 601 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Valentina Bertolini
    • 1
  • Isabella Gandolfi
    • 1
  • Roberto Ambrosini
    • 2
  • Giuseppina Bestetti
    • 1
  • Elena Innocente
    • 3
  • Giancarlo Rampazzo
    • 3
  • Andrea Franzetti
    • 1
  1. 1.POLARIS Research Centre, Department of Environmental Sciences (DISAT)University of Milano-BicoccaMilanItaly
  2. 2.Department of Biotechnology and BiosciencesUniversity of Milano-BicoccaMilanItaly
  3. 3.Department of Environmental Sciences, Informatics and StatisticsUniversity of Ca’ FoscariVeniceItaly

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