Biocatalysts for drinking water treatment

The chlorine oxyanions perchlorate, chlorate, and chlorite present human health risks, and the primary exposure route is drinking water. For both ion exchange and biological methods for perchlorate removal, co-contamination with nitrate presents a problem. We have shown that the enzymes involved in perchlorate degradation are functional in the presence of nitrate and in real-world waters, suggesting potential for using them as biocatalysts in a cell-free system. Results of life cycle assessment and technoeconomic analysis support the potential of this technology and have provided key technology development targets. Current work is focused on testing a variety of options for incorporating biocatalysis in drinking water treatment, with continued life cycle assessment and technoeconomic analyses to quantify the commercial potential and environmental impacts of such an approach.

Future work could include integrating this system with a mammalian transport protein inserted in a synthetic membrane, allowing concentration of perchlorate for degradation. Unlike aquaporins, this transport protein has a directionality, raising new fundamental questions and technical challenges for its insertion into synthetic polymers.

We view this project as proof of concept for a platform that has a wide range of applications for environmental engineering, allowing a mix-and-match approach without the constraint of maintaining viability or the risk of release and reproduction as in a biological process.

Funding: NSF CBET and US Army ERDC

Collaborators: Dr. Jeremy Guest (Illinois), Dr. Charlie Werth (UT Austin), Drs. Don Cropek & Irene MacAllister (ERDC-CERL, US Army)

Students: Justin Hutchison, Indran Kamalanathan, Manish Kumar, Kellen Mobilia, & Sean Poust

Related publications:

Hutchison, J. M., J. S. Guest, and J. L. Zilles. 2017. Evaluating the development of biocatalytic technology for the targeted removal of perchlorate from drinking water. Environmental Science and Technology 51(12):7178–7186. doi: 10.1021/acs.est.7b00831

Mobilia, K. C., J. M. Hutchison, and J. L. Zilles. 2017. Characterizing isozymes of chlorite dismutase for water treatment. Frontiers in Microbiology. accepted.

Hutchison, J. M., and J. L. Zilles. 2015. Biocatalytic perchlorate reduction: kinetics and effects of groundwater characteristics. Environmental Science: Water Research and Technology.  Advance Article available online 9 September 2015. DOI: 10.1039/C5EW00176E

Hutchison, J. M., S. K. Poust, M. Kumar, D. M. Cropek, I. E. MacAllister, C. M. Arnett, and J. L. Zilles. 2013. Perchlorate reduction using free and encapsulated Azospira oryzae enzymes. Environ. Sci. Technol. 47(17):9934-9941. doi: 10.1021/es402081b. Epub 2013 Aug 23.