Microbes are in the food we eat, the air we breathe and the water we drink. Additionally, each liter of sea water contains up to a billion bacteria. Therefore, it is no surprise that microbes inhabit the human body. In fact, every person has more than 10 times as many microbes living on and inside their body as they do human cells.
Although most frequently associated with disease, our microbial hitchhikers help us much more than they harm us. How? By controlling many of the biological processes that are essential to our survival, including the maintenance of our skin and the digestion of our food. Each person’s digestive track alone harbors about three pounds of bacteria.
“If all of Earth’s microbes died, so would everything else, including us,” says Matt Kane of the National Science Foundation. “But if everything else died, microbes would do just fine.” Therefore, Kane concludes that “we need microbes more than they need us.”
Despite the importance of microbes, scientists have only been able to study less than one percent of the estimated millions of microbial species that live on Earth. Why so few? Because microbes have strict nutritional requirements and interact with one another in complex ways; this makes it impossible to grow the overwhelming majority of them in the laboratory.
We currently use bacteria to treat wastewater, and we are just now beginning to understand the relationships between bacteria that may make the treatment process work more effectively. These include the metabolic pathways that are used by the bacteria to complete the degradation and stabilization of the waste sent to us each day. By understanding these pathways we may be better able to optimize the treatment of wastewater.