By Winston Lindqwister, Summer Intern in Dr. Claudia Gunsch’s lab
It may be a surprise to you, but some of the most impactful machines on this planet are smaller than a pinhead. Forged by millions of years of evolution, bacteria and fungi have established themselves as nature’s ultimate garbage disposal unit, chewing through all manner of waste substances in the environment. Although we often take these microscopic dynamos for granted, these tiny bio degraders are brimming with potential to help us shape our environment—and very well could be the key to saving us from some of the dangers lurking in our soils.
Contaminated soil is a health hazard—especially those soils affected by polycyclic aromatic hydrocarbons (PAHs). Oftentimes invisible to the naked eye and difficult to remove, chemically removing PAHs from soil can require complicated and expensive processes. To make matters worse, the time and labor required to chemically remediate the vast swathes of land affected by PAHs make modern, man-made methods of pollutant disposal inefficient at best. Thankfully, it’s been well established that some of the bacteria and fungi naturally present in the environment are natural PAH degraders and can help with the problem of PAH remediation. However, questions remain on how to effectively use these microbes to address this widespread contamination issue.
As a civil engineering student, I’ve always been interested in the problem-solving process. That is, the steps needed to put research into practical use and how to best utilize scientific findings to improve our quality of life. Naturally, I was intrigued by the idea of using microbes that are natural degraders to create a cost-effective solution to a persistent problem that has plagued our natural ecosystems for decades. The focus of my research isn’t necessarily centered on discovering which microbial communities would work best for degrading PAHs, but rather how we can effectively deploy them in a complex environment.
I spent part of my summer focusing on carbon amendments (soil additives) that could prove to be the perfect vessel for deploying PAH-degrading microbes. To effectively degrade pollutants in sediment, these microorganisms must first anchor themselves and form a biofilm. Biofilms are a sort of mini bacterial community where these organisms have structural protection and a strong foundation to grow on. The idea is to use carbon amendments such as activated carbon as a platform to grow biofilms, creating an easily dispersed media for introducing microbial colonies to polluted areas. The added benefit of these carbon amendments is their natural tendency to “stick” to PAHs, giving the microbes an easy means to reach their desired target molecule and facilitate remediation.
The questions I worked to answer this summer were: 1) at what rate do PAHs adhere to certain carbon amendments (specifically activated carbon) under various concentration levels; and 2) can these findings can be used as a basis to compare carbon amendments of differing sizes and colligative properties?
Another key question to address is how carbon amendments can affect bioavailability for remediation. Basically, how effective are carbon amendments at sticking to PAHs, and will their relative stickiness create problems for bacterial colonies attempting to digest them? With these questions in mind, we can tap into these microbial remediation powerhouses as effective tools for degrading environmental pollutants.