Metabolic activity of airborne bacteria
Dr. Valdis Krumins, Department of Environmental Science, Rutgers University
About Dr. Krumins
Dr. Krumins has over fifteen years experience in monitoring and control of microbiological processes in natural and engineered environments. He holds a B.S. in agricultural engineering from Penn State University and a Ph.D. in biological resources engineering from the University of Maryland. He has worked as a consultant on contaminated site remediation, designed and tested systems for resource recovery on long duration space missions, and been process control engineer at one of the largest wastewater treatment plants in the country. As a research assistant professor at Rutgers, he investigates and tries to optimize microbial processes in sediments, wastewater, and the air.
About the Seminar
There is mounting evidence that microbes within cloud or fog droplets are metabolically active, consuming substrates and growing. In addition to expanding our understanding of where life can occur, this discovery impacts local and global carbon cycling, and climate. Our group is investigating whether bacteria in “clear” air, outside of water droplets, can be active as well. A cubic meter of outdoor air contains up to 105 bacterial cells, which, because of their size, can remain aloft for days. Ambient air contains enough water and food in the form of volatile organic compounds (VOC) to support life. Using rotating bioaerosol bioreactors, we show that airborne bacteria produce ribosomes, proteins and DNA, and thus are metabolically active.
Sphingomonas aerolata, a psychrotolerant bacterial species originally isolated from air, produces ribosomes when exposed to acetic acid or ethanol while airborne. It also expresses proteins related to oxidative phosphorylation and protein export. Membrane and DNA repair proteins are positively correlated with culturability, and so are possible targets for rapid molecular bioaerosol viability assays. We are currently using incorporation of 13C from labeled substrates into DNA to investigate growth. Preliminary data indicate heterotrophic growth on VOCs and photosynthesis by cyanobacteria while airborne. Thus we show that air can be a transient habitat for bacteria, impacting global dispersal of microbes, carbon cycling and climate.