Air conditioning (AC) systems cool and dehumidify air. The process deposits moisture on the cooling coils, creating an environment conducive to microbial growth. We know very little, however, about the microbes that grow on AC units or how these microbes affect and interact with the microbial populations of the buildings they cool. This grant supports Jordan Peccia, associate professor of environmental engineering at Yale, who will lead a multidisciplinary team in a pilot study examining how the microbial and chemical emissions of commercial air conditioning units impact the microbiome of occupied spaces. Over two years, Peccia and his team will characterize the bacterial and fungal communities present on the cooling coil surfaces of commercial air conditioners, estimate the microbial volatile organic compound (MVOC) emission rates from commercial AC units, and quantify the influence that AC emissions have on the indoor air and surface microbiome of occupied spaces. The team will initially sample 40 different commercial air conditioning units and use these samples to examine how microbial population structure is affected by a host of environmental variables, including outdoor climate, coil moisture, and coil temperature. They will then measure AC microbial emission rates and the characteristics of emitted microbes to study how these correlate with the surface and air microbiome composition in the buildings these units cool.

This grant supports an initiative by Andy Taylor at the University of Aberdeen, in collaboration with Urmas Kхljalg at the University of Tartu in Estonia, that aims to significantly expand the UNITE database, a key resource used by mycologists in the genomic identification of fungi. The UNITE database contains genetic sequences of known fungi, which allows researchers to identify unknown fungi collected at field sites by matching the genetic sequences of collected samples to the master samples in the database. Unfortunately, the UNITE database lacks reliable standard sequence data on many of the fungi commonly found in indoor and built environments, which deprives researchers working on the microbiology of the built environment of a powerful tool for taxonomic identification. Over the next two years, Taylor and Kхljalg will target and sequence previously unsequenced fungal strains relevant to human and built environments, hold two sequence annotation workshops that aim to improve the quality of available sequence data, and develop metadata standards and protocols that will enable better inter-database comparison of collected fungal data.

Funds from this three-year grant support efforts by Jonathan Eisen at the University of California, Davis to provide key intellectual infrastructure support and services to the growing multidisciplinary community of researchers working in indoor microbial ecology. Through the Microbiology of the Built Environment network (microBE.net) Eisen organizes meetings and workshops, provides a hub for resource and information sharing, disseminates results and funding opportunities, aids in the dissemination of data collection and analysis standards and protocols, and helps bridge disciplinary boundaries by connecting researchers in biology, informatics, architecture, and the building sciences. Over the next three years, Eisen will continue the work of microBE.net, providing additional resources to the MoBE community in six thematic areas:  antimicrobials in the BE; nonhumans in the BE; extreme BEs; BE water systems; technical needs for the MoBE field; and general MoBE interests. Activities targeting each theme will include web development, meeting and workshop organization, social media, pilot research projects, creation and curation of open textbooks, development of a community-driven genome sequencing program, writing of scholarly articles on research and tool development, and continued development of the microBEnet blog with further recruitment of MoBE scholars to contribute to the development of modules for MoBE educational activities (e.g., college courses).

This grant provides two years of continued support to the University of Oregon’s Biology and the Built Environment Center (BioBE). Led by microbiologist Jessica Green and architect GZ Brown and founded with the assistance of a 2010 Sloan Foundation grant, the BioBE Center aims to develop a predictive science of the built environment microbiome by bringing together a multidisciplinary research team of microbiologists, engineers, architects, and building experts. Over the next two years, Center researchers will launch a number of research projects that attempt to expand our understanding of how ventilation, structure, and daylight influence the composition and function of indoor microbial communities. Specific topics to be studied include how antimicrobial compounds influence the indoor microbiome and how that influence is mediated by building design, how restricting exchange with outside air affects community composition indoors, and whether earlier findings suggesting that design influences the microbial dust communities are generalizable across building types. In addition to supporting the Center’s research, additional grant funds support the Center’s training and outreach activities designed to bring new talent into the field and disseminate research results widely among the scholarly community and public.

Recent field investigations of the microbiology of the built environment have demonstrated that the biological composition of indoor air and building surfaces is vastly more complex than previously thought. Very little is known, however, about the fundamental ecology of the microbes that colonize these locations. This grant supports efforts by a research team led by Jack Gilbert, associate professor in the Department of Ecology and Evolution at the University of Chicago, to develop new knowledge about the metabolism of indoor microbial communities using experimental and modeling approaches. The team plans to examine how different building surface materials, under variable temperature and humidity conditions, influence microbial growth, evolution, and survival and will develop a mechanistic model that can predict the succession and metabolism of microbial communities on surfaces. Dr. Gilbert and his team will seed tile, laminate, wood, and metal surfaces with defined microbial consortia acquired from human skin, dog fur, and soil, and observe microbial community succession under various temperature and humidity conditions. Their observations will test a number of important hypotheses, including how humidity affects the diversity of metabolically active bacteria and fungi, whether taxonomic diversity of active microbes decreases over time, how air temperature affects cell grow rates, and how the bacteria-to-phage ratio in a given microbial community affects overall community size.   If successful, the project will result in new knowledge about bacterial succession in the built environment and provide a mechanistic model to improve understanding of the metabolic activities of indoor microbes. The team plans to share their findings through publications in peer-reviewed journals, presentations at meetings and conferences, and through the use of social and traditional media. At least two postdoctoral fellows and two graduate students will be trained.