AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Potential for Metabolic Activity of Bioaerosols
Valdis Krumins, GEDIMINAS MAINELIS, Lee Kerkhof, ValaRae Partee, Donna Fennell, Rutgers, The State University of New Jersey
Abstract Number: 758 Working Group: The Indoor Microbiome
Abstract While many microorganisms have been identified and enumerated in ambient air, there has been very little exploration of microbial activity and potential for growth in natural bulk air. Natural air contains oxygen, water, and substrates in the form of volatile organic compounds (VOCs) that potentially allow for microbial growth while airborne. The objective of this study is to determine whether bacteria present in ambient air are active or growing.
Bioaerosols from 1 m$^3 air samples were collected from four sites across New Jersey using filters (Supor, Pall, Port Washington, NY) and by liquid impingement using Biosamplers (SKC, Eighty Four, PA). The liquid samples were divided into four aliquots and enriched in minimal media supplemented with 1 mM of one of the following VOCs: methanol, ethanol, acetic acid, and acetone. The prokaryotic and eukaryotic components of the microbial communities of the enrichments were analyzed by denaturing gradient gel electrophoresis.
Enrichment cultures were aerosolized into rotating bioreactors which can maintain bacteria-sized particles airborne for several days. The reactors are made from 0.32 m$^3 stainless-steel drums equipped with temperature, pressure and humidity sensors. The bioaerosols in the drums were supplied with $^(13)C-labeled or unlabeled acetic acid (240 ppbv) or ethanol (20 ppmv) and incubated for two days at room temperature. Stable isotope probing of the 16S rRNA gene was used to explore whether new DNA had been synthesized.
Sphingomonas aerolata, a psychrotolerant bacterium previously isolated from indoor air, was also tested in bioreactor incubations. Increased ribosomal RNA content of ethanol-fed compared to starved bioaerosols suggests metabolic activity in the presence of the volatile substrate. A proteomics approach is also being used to assess activity.