IHPH Research Projects


Andrea Holmes, PhD, Professor of Chemistry at Doane University

IHPH Research Interests




The Good and the Bad about Biofilms in the Environment

I serve as the Principal investigator of the Center of Undergraduate Research in Biofilms (CURB). Within CURB, I have two major research interests; 1.) Bioremediation of polluted water (the good), 2.) Surface chemistry for biofilm inhibition (the bad).


What are Biofilms and what is their relevance to the environment?

Biofilms are a group of microorganisms in which cells adhere to abiotic or biotic surfaces through extracellular polymeric substances. In medical settings, biofilms are resistant to antibiotics and are a major problem because of hospital acquired infections during surgery and or on artificial implants.1 However, what is less known about biofilms is that they are also very beneficial in environmental bioremediation, such as waste water treatment.2 A recent study in Sweden demonstrated that biofilms that grow in water supplying pipes have the ability to filter out contaminants.3 Since it has been shown that industry and agriculture are major contributors to water pollution,4 biofilms may present an attractive natural alternative for remediation and bio-based water clean-up, especially since pesticides have caused major health impacts in humans.5


Research Question 1: Can biofilms be used for bioremediation of pesticide polluted water?

Pesticides, such thiamethoxam, clothianidin, and atrazine are used in our studies. These pesticides are known to have detrimental effects to human health, and are particularly prevalent in the Midwest.5

The first bacterial species for biofilms that will be used for this study is from the Sphingomonas family which can be can be found in high quality water from pipes that supply housholds.3 This bacterial biofilm can consume non-desirable organic material, toxic chemicals, and various types of plastic.   

Research Question 2: Can complex polymeric surface coatings on abiotic surfaces prevent bacterial attachment and biofilm formation?

Marine biofilms adhering to ships and other man-made substrates present a major economic and environmental problem as increased friction leads to increase fuel consumption.6 Currently used antimicrobial coatings, such as tributyltin, are toxic to marine life,7 and therefore is an urgent need for non-toxic chemically modified surfaces.

At Doane, my research evaluates the performance of novel surface coatings to prevent bacterial attachment, inhibit biofilm formation, or significantly modify biofilm growth.



1. Costerton, J. W., Montanaro, L. & Arciola, C. R. Biofilm in implant infections: its production and regulation. Int. J. Artif. Organs 28, 1062–1068 (2005).

2. Amulya, K., Dahiya, S. & Mohan, S. V. Building a bio-based economy through waste remediation: Innovation towards sustainable future. in Bioremediation and Bioeconomy (ed. Prasad, M. N. V.) 497–521 (Elsevier, 2016).

3. Lührig, K. et al. Bacterial Community Analysis of Drinking Water Biofilms in Southern Sweden. Microbes Environ. 30, 99–107 (2015).

4. Moss, B. Water pollution by agriculture. Philos. Trans. R. Soc. B Biol. Sci. 363, 659–666 (2008).

5. Cimino, A. M., Boyles, A. L., Thayer, K. A. & Perry, M. J. Effects of Neonicotinoid Pesticide Exposure on Human Health: A Systematic Review. Environ. Health Perspect. 125, 155–162 (2017).

6. Schultz, M. P., Bendick, J. A., Holm, E. R. & Hertel, W. M. Economic impact of biofouling on a naval surface ship. Biofouling 27, 87–98 (2011).

7. Tornero, V. & Hanke, G. Chemical contaminants entering the marine environment from sea-based sources: A review with a focus on European seas. Mar. Pollut. Bull. 112, 17–38 (2016).



Student Researchers

Hunter Kleinschmidt

Bioremediation Studies with Opportunistic Biofilms for Pesticide Elimination in Agricultural Water Run Off
Hunter Kleinschmidt

Biofilms are a group of microorganisms in which cells adhere to abiotic or biotic surfaces through extracellular polymeric substances.1,2 Biofilms are naturally occuring throughout the environment and can play a beneficial role in controlling the biogeochemical flows of an ecosystem.5 Bioremediation is an example of biofilm application where specific biofilm communities are used to remove or neutralize pollutants from a contaminated site.1 This research project examines the possibility of manipulating beneficial biofilms to remediate and biodegrade pesticide contamination in waterways negatively impacted by agricultural run off. This is of high interest for agriculturally intense areas when considering the high amount of pesticide runoff from cropland and the negative effects of pesticides on humans and the environment.3,4 A high-throughput microfluidic bioreactor called Bioflux will be used study the biofilm efficiency of pesticide degradation in water samples present with pesticides, such as atrazine and glyphosate. This project is working toward the feasible application of an optimal biofilm community that can effectively degrade and remediate pesticides from agriculture run-off in hopes to improve human and environmental health.

1. Singh, R., Paul, D. & Jain, R. Biofilms: implication in bioremediation. Trends Microbiol. 14, 389–397 (2006).
2. Amulya, K., Dahiya, S. & Mohan, S. Building a Bio-Based Economy Through Waste Remediation: Innovation Towards Sustainable Future. in Bioremediation and Bioeconomy (ed. Prasad, M.) 497–521 (Elsevier, 2016).
3. Carozza, S., Li B., Elgethun, K., Whitworth, R. Risk of Childhood Cancers Associated with Residence in Agriculturally Intense Areas in the United States. Environmental Health Perspectives. 4, 559-563 (2008).
4. Cimino, Andria M., Abee L. Boyles, Kristina A. Thayer, and Melissa J. Perry. 2017. "Effects of Neonicotinoid Pesticide Exposure on Human Health: A Systematic Review." Environmental Health Perspectives 125, no. 2: 155-162. Academic Search Premier, EBSCOhost (accessed June 29, 2017).
5. Luhrig, K., Canback, B., Paul, C., Johansson, T., Persson, K., Radstrom, P. Bacterial Community Analysis of Drinking Water Biofilms in Southern Sweden. Microbes Environ. 30, 99-107 (2015).