Development of a high-volume aerosol collection system for the identification of air-borne micro-organisms


Dr Gary L. Andersen, Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, L-441 PO Box 808, Livermore, CA 94551, USA (e-mail:


Aims: A high-volume aerosol collector was developed to efficiently capture airborne bacteria in order to assess levels of diversity in the air.

Methods and Results: Particulate matter was collected on a device designed to filter 1·4 × 106 litres of air in a 24 h period on a 1-lm pore size polyester membrane. Methods were optimized for extraction of genomic DNA from the air filter concentrate. Preparation times of 90 s with 0·5-0·05 mm diameter zirconia/silica beads yielded the highest concentration genomic DNA that was able to support PCR. A 24-h air sample was taken in Salt Lake City, Utah and the microbial composition was determined by the amplification and sequence analysis of 16S ribosomal DNA fragments.

Conclusions: Sequence analysis revealed a large diversity in the type of microbial species present including clones matching the sequence of Clostridium botulinum. The primary components of the aerosol sample included many different spore-forming bacteria as well as more fragile members of the Proteobacteria division.

Significance and Impact of the Study: The high-volume air collection and genomic DNA recovery system allows for the rapid detection of both cultivable as well as culture-resistant organisms in the environment.