Engineering a self-cleaning environment

UMN researchers create self-cleaning Biohubs to mitigate the impact of pollutants in Minnesota’s waterways

by Lauren Holly

Minnesota’s Iron Range is dotted with active and abandoned mining sites. Left untreated, runoff from these sites can flow into the environment and release heavy metals and organic pollutants, ultimately endangering wildlife and threatening human health.

But what if we could engineer the environment to clean itself? With support from the MnDRIVE Environment initiative, researchers in the BioTechnology Institute’s Schmidt-Dannert lab are developing Biohubs using genetically engineered proteins capable of breaking down heavy metals and removing toxins from mine drainage and other industrial sites.

Biohubs take advantage of a protein’s natural tendency to self-assemble into stable shell-like structures. Their porous surface converts harmful metals and organic pollutants into non-toxic components.

Based on similar structures found in nature, the lab’s model Biohub converts toxic mercury compounds into a form that can be released safely in the environment. The process relies on modified proteins that bind toxins while enzymes, small proteins capable of catalyzing biochemical reactions, convert mercury to its inert elemental form. The system is “self-cleaning” because the enzymes remain active inside the Biohub until it encounters the next metal, and restarts the process.

On-site, the Biohubs are placed in glass or metal columns that act as a filtration system; contaminated water enters through one end of the column and exits at the opposite end of the column free of toxins.

Using enzymes to clean the environment has advantages. They are versatile and leave no toxic residue, but enzymes found in nature are not always stable, and Schmidt-Dannert’s team needed a way to protect and stabilize the proteins. Enter Minnepura Technologies; a biotech startup co-founded by University of Minnesota Professors Alptekin Aksan and Lawrence Wackett. Minnepura specializes in the development of biocomposite materials designed to encapsulate and protect proteins. Minnepura and will encase the Biohubs in an easily adaptable, light-weight silica that supports the structure over time.

“Initial studies will focus on remediation of heavy metals from mine drainage, but the system could also be applied to clean up of pesticide-contaminated soil or water near agricultural land,” explained Maureen Quin, a lead researcher on the project.

Schmidt-Dannert believes engineered proteins hold considerable potential as a platform technology for sustainable bioremediation. “If we can get this to work with organic compounds, this solution could be very versatile and able to convert a variety of different pollutants.” In states like Minnesota trying to balance the competing demands of industry and environmental stewardship, Biohubs may help the environment clean itself.

Lauren Holly is an intern in the BioTechnology Institute’s Science Communications Training Program.