1: Construct a building
2: Spray bacteria and fungi all around the building
3: Wait a few weeks and then open for business
Sound crazy? Not necessarily. This scenario, or something like it, is the kind of application that could theoretically come out of current studies on the microbiology of the built environment.
With each passing week it seems that we learn more about the beneficial (in fact critical) roles that microbes play in our own bodies. The collection of microbes that reside within us (the “human microbiome”) plays a role in everything from digestion to mental health. Disrupting this ecosystem with antibiotics has well-documented negative impacts and attempts to replace or supplement these bacteria are common. “Probiotics”, officially “Live microorganisms which when administered in adequate amounts confer a health benefit on the host” are very common these days and can be found in any supermarket.
There are really two parts to the concept of probiotics. The first is that there are microbes that have a direct benefit to the host, such as the breakdown of certain compounds, or the modulation of immune function. Secondly, having a thriving ecosystem of microbes probably makes it much harder for “bad” microbes to gain a foothold. This is well-documented for example in the case of antibiotic usage where treatment is often followed by an overgrowth of yeast such as Candida albicans.
Now let’s think of a building as a host, and we can even talk about the “microbiome” of that building. Each building has a different microbiome, and some are healthier (for their human occupants) than others.
In some portions of the built environment, there are indeed microbes that directly play very important roles, such as certain bacteria used in wastewater treatment. We already make use of “probiotics” in this case, although we don’t use that term.
More interesting is the case of habitable built environments such as houses, offices, space stations, or hospitals. Here the parallel is possibly closer to the yeast example from above… if there are few microbes in an environment that means there are many more available niches for “bad” microbes to find a home. Normally when you construct a building the microbiome of that building is populated at random and you might end up with good microbes, neutral microbes, as well as bad microbes. Perhaps if you first seeded the building with only good and neutral microbes, you could create an environment much less accommodating for bad microbes. This would truly be a case of “probiotics for buildings”.
There’s even a parallel for antibiotic treatment in humans, in the form of building wide sterilization and insulation from the outside such as in a hospital. And in fact, there’s some recent evidence (such as the work from Jessica Green at the BioBE Center) that these sterilized and insulated environments contain a much higher proportion of potentially pathogenic organisms than naturally ventilated spaces or the outdoors.
Maybe “probiotics for buildings” isn’t such a crazy idea after all