Harnessing Microbes for Better Health

Harnessing Microbes for Better Health

UMN researchers study how bacteria can contribute to safer drinking water

By Shayna Korol and Charlie Kidder

Clean water doesn’t happen by accident. Before it is ready to drink, water must be purified of microbes and other pollutants that are harmful to human health. Most drinking water in the United States is treated through biofiltration, a process that uses filter media, such as sand, anthracite coal, or granular activated carbon (GAC), with attached communities of bacteria to remove harmful microorganisms as well as dissolved contaminants. It seems counterintuitive to cultivate bacteria in a drinking water treatment facility, but it is important to realize that not all bacteria are harmful. In fact, many bacteria are beneficial and can be utilized to improve water quality. 

Biofilters use a granular filter medium such as sand, which is covered with a thin bacterial layer known as a biofilm. As untreated water passes through the biofilter, the grains of filter medium collect the microorganisms and other particles from the incoming water while the biofilm “catches” dissolved pollutants, including nutrients and organic contaminants like pesticides. While water treatment never completely eliminates microbes, biofiltration aims to keep the concentration of harmful pathogens low enough to prevent people from getting sick. 

Not all biofilters are created equal. Some biofilters that use sand as a filter medium are known as slow sand filters. As the name suggests, these filters work relatively slowly, making it difficult for an urban water treatment facility (like the city of Saint Paul’s) to process 50 million gallons a day. Tim LaPara and Ray Hozalski, University of Minnesota professors in the department of Civil, Environmental, and Geo-Engineering and the BioTechnology Institute, study differences between biofilters that can impact water quality. “The slow sand filters don’t work well [for large metropolitan areas like the Twin Cities],” says LaPara. Water treatment plants for large cities typically employ “rapid filters”, which process water at a rate that is more than 10 times greater than slow sand filters. Hence, the number of filters needed is much more manageable, and the plant size is reasonable.

In the early 2000s, Saint Paul had a water quality issue because of a substance called geosmin. Although it is not harmful to human health, geosmin has an unpleasant taste and odor. In order to mitigate geosmin’s effects on the water supply – and cut down on hundreds of yearly complaints from Saint Paul residents – the city installed granular activated carbon (GAC) filters. “The idea was the geosmin would stick to those filters, and water would taste better,” says LaPara. 

In Saint Paul, water quality complaints plummeted by about 90 percent after the GAC filters were put in place. “They went from 250 to 300 complaints down to 15 to 30 complaints per year,” says LaPara, a tremendously low number for a city as big as Saint Paul. 

Like Brita water filters in kitchens across the world, the thought was that the GAC filters would eventually have to be replaced. Implementing the filters cost $5 million, and removing and replacing them would cost the city another $5 million each time. Hozalski estimated that the filters would work for at least five years. Surprisingly, the filters kept working well even after five years. Instead of simply accumulating on the GAC filters as the researchers assumed would eventually happen, the geosmin also was being consumed by the bacterial communities on the biofilm as it passed through the filter. The GAC “takes up all the geosmin during the summer and then slowly dissolves it out the rest of the year, and it dissolves it so slow[ly] that the microbes eat it and nobody ever taste[s it],” explains LaPara. Ten years passed, and the researchers found that the filters worked as well as they did the day they were installed. Thus, the GAC filter media was being bioregenerated, allowing for a sustainable treatment process.

“If the bacteria can biodegrade the compounds [that need to be removed], then you don’t have to replace the media because they can basically take care of it naturally,” says Hozaski. The work by the bacteria on the filters provided millions of dollars in savings. 

As an outgrowth of the GAC filter research that began in the early 2000s, the scientists attempted to understand how the microbial communities in these biofilters evolve and function. In a 2018 journal article, Ph.D. student Ben Ma, together with Hozalski and Prof. Bill Arnold, demonstrated that biofilters can remove a wide variety of trace organic contaminants, including pesticides and pharmaceuticals. Hozalski also lead a study by a research team, which included Ma, LaPara, and Ashley N. Evans from the consulting firm Arcadis, in which samples of filter media were collected from biofilters throughout North America. The researchers found that the microbiome of drinking water biofilters is affected by both environmental factors and filter design. 

They published the basic science study in FEMS Microbiology Ecology. “We were trying to understand how different these biofilters are from location to location,” LaPara says. While Minneapolis filters are very similar to Saint Paul filters, they are different from filters in California. 

“Geographic location seems to have some bearing on the [microbial] communities that evolve, and so the closer that water plants are together, the more similar the communities are; the further they are apart, the more different,” Hozalski explains.  

In 2020, the researchers published a paper in Environmental Science & Technology investigating the effects of biofilter design on both the microbiome of the filter media and filtered water itself. This study, also an extension of the earlier GAC filter research, used GAC-sand and anthracite-sand biofilters. Hozalski also served as lead researcher.

While the biofilters reduced bacterial abundance in the water by about 70 percent, they did not significantly affect the microbial composition that remained in the filtered water. These results suggest the biofilms mostly affect water quality by removing pollutants and nutrients rather than changing the microbial composition of the filtered water. “The biofilter does a lot, but it doesn’t add different microbes to our water,” LaPara says.

By shedding further light on how biofilters function, the researchers are setting the groundwork for better filters – and cleaner water. Hozalski said, “I have been working on biofilters since my Ph.D. studies in the early 1990s, and I still have a lot to learn! They are both simple in design yet decidedly complex when you dig into them.”

Byproduct

Byproduct

Byproduct

Byproduct

Art installation at the Fulton brewery taproom sheds light on MnDRIVE sponsored sustainable wastewater treatment research.

Byproduct, a new site-specific installation by artist Aaron Dysart, opens at the Fulton Brewery Taproom on September 23 and runs through October 23, 2021. Byproduct will carbonate the façade of the taproom with shifting colors generated from an enormous mirror ball. The colors display data from a sustainable wastewater research project conducted by Paige Novak and her team at the University of Minnesota.

We often overlook the carbon dioxide bubbles drifting up the sides of a pint glass gathering to head. On the one hand, they are just a byproduct of a yeast cell. On the other hand, they are a refreshing grounding in the present moment— and the beer just doesn’t taste right without them. In Byproduct, Dysart uses this visual language of carbonation to speak to innovative research underway at Fulton’s brewery. The installation, which displays some of the team’s data as colorful ‘bubbles’ on the taproom facade, celebrates the continuing push to make the world a better place.

Manufacturing creates waste, and brewing beer is no different. Not only does brewing generate a high volume of wastewater, but this wastewater is also full of carbon-containing compounds that require a lot of energy to treat using standard technology. However, other treatment options operate differently, using bacteria to make energy instead of using energy during wastewater treatment.  

Novak and her team are working on a treatment technology for small to mid-size industries that generates energy (in the form of methane gas) and removes carbon-containing compounds. The collaboration with Dysart allowed the team to share their research with the public as they test their scalable process that treats wastewater onsite while making energy for use at the brewery.

Dysart’s installation presents two colorful light shows comparing the two treatment methods set up side-by-side, treating wastewater at the Fulton Brewery. The first compares the amount of usable energy produced by the Novak lab’s experimental technology with the existing system, which works well but is high-maintenance, energy-intensive, and expensive to use. The second explores the reduction of carbon-containing waste compounds realized through the pilot at Fulton’s brewery. 


 

Aaron Dysart is a sculptor who is interested in using visual language and spectacle to give hidden stories a broader audience. His environmental interventions showcase his love of light shows, fog machines, and data, while his objects showcase his love of a material’s ability to carry content. He has received awards from Franconia Sculpture Park, Forecast Public Art, The Knight Foundation, and The Minnesota State Arts Board, and his work has been in Art in America Magazine, Hyperallergic, Berlin Art Link, and other publications. He has shown nationally and partnered with local and national organizations including the National Park Service, Army Corp of Engineers, NorthernLights.mn, and Mississippi Park Connection. Aaron is currently a City Artist through Public Art Saint Paul. He is embedded in the city of St. Paul, and operates his studio in northeast Minneapolis.

Paige Novak is a professor and the Joseph T. and Rose S. Ling Chair in Environmental Engineering in the Department of Civil, Environmental, and Geo- Engineering at the University of Minnesota. Among other projects, Novak and her team are working on the development of a new type of treatment technology that relies on the encapsulation of bacteria into small, gel-like beads that can be easily deployed and retained—perfect for use at small industries such as craft breweries. This technology treats the waste, and in the process, generates energy in the form of methane gas that can be used on-site. For Dysart and Novak’s collaborative project, funded by the MnDRIVE: Environment Initiative at the University of Minnesota, Novak deployed a small pilot-scale system using these encapsulated bacteria at the Fulton brewery to treat their wastewater in real time, comparing it to a much more operationally and energy-intensive treatment technology. 

Bill Arnold and Natasha Wright were collaborators in the research. Kuang Zhu, Siming Chen, and Olutooni Ajayi also worked on the project

Byproduct is funded by a McKnight Project Grant through Forecast Public Art, and a MnDRIVE: Environment Demonstration Grant through the University of Minnesota.

Photo: Aaron Dysaart © 2021

 

 

Is PFAS a Problem in Municipal Compost?

Is PFAS a Problem in Municipal Compost?

MnDRIVE brings industry and regulators together to weigh costs, benefits, solutions

by Mary Hoff 

What should researchers be researching? With many needs and finite resources, that’s an important question for MnDRIVE Environment, a partnership between the University of Minnesota and the State of Minnesota that brings the power of University inquiry and innovation to bear on challenges industries face related to clean air, water, and land.

In early 2020, the initiative invited private sector and state agency representatives to discuss issues in need of attention related to per- and polyfluoroalkyl substances or PFAS. This class of chemicals historically has been used in a wide spectrum of consumer goods and has since been implicated as a land and water contaminant linked to a range of health risks. Of particular concern is the fact that PFAS chemicals have started cropping up at municipal compost facilities that turn materials such as grass clippings and food waste into a nutrient-filled substance that is used to enrich soil.  

One of the businesses represented at the meeting was the Shakopee Mdewakanton Sioux Community (SMSC) Organics Recycling Facility. The facility takes in 70,000 tons of materials every year to make compost, compost blends, and landscaping mulch. It has tested its products and found PFAS levels to be well below those that the Minnesota Pollution Control Agency (MPCA) considers a health concern in residential soils. PFAS has shown up in water that drains off piles of materials that are in the process of breaking down, says MPCA composting and recycling specialist Kayla Walsh (as it has for other composting facilities around the state). The test results have facility managers looking for ways to continue to do good while preventing future problems.

The topic is a particularly hot one for SMSC because it would like to open a larger facility to meet increasing demand from community composting.

“We know composting is good. We’re amending the soil,” says SMSC biomass processing assistant manager Dustin Montey. At the same time, he adds, “we don’t want to be introducing a harmful substance back into society” by producing soil amendments containing PFAS.

Erin Skelly, environmental and compliance technician for the facility, notes that SMSC is grounded in the Native American principle of caring for the Earth with the next seven generations in mind. A participant in the 2020 MnDRIVE-hosted meeting, Skelly sees a need for research to find the source of the PFAS and how to get it out of the waste stream so it doesn’t end up in compost.

“There’s a lot that’s unknown about PFAS,” she says. “If it’s in compost and in soil, does it leach out? Does it get into groundwater? Do plants absorb that? There’s a lot of opportunity for research.”

MnDRIVE Environment funding is earmarked specifically for remediation. However, it also works upstream to stimulate discussion and connect stakeholders to collaborate on identifying and characterizing problems that remediation can help solve.

“Once we know where PFAS is and where it is coming from, then these issues can be put forward to remediate. That’s sort of the sweet spot where MnDRIVE funding programs come into play,” says MnDRIVE Environment industry and government liaison Jeff Standish.

For example, University of Minnesota environmental health researcher Matt Simcik and environmental engineering researcher William Arnold have been developing technology to keep PFAS from moving from landfills into groundwater. MnDRIVE Environment funding is supporting this work which, upon completion, might be used to protect water at compost sites.

MnDRIVE Environment will be continuing conversations this spring around strategies for addressing PFAS contamination in the environment. Between entities like SMSC that are seeking to protect the planet, and MnDRIVE, which stands ready to bring the power of University research to the task, the hope is that society can continue to reap the benefits of composting without exacerbating the PFAS problem, and perhaps proactively solving it.

Fighting Farmland Pollution with Fungi

Fighting Farmland Pollution with Fungi

With support from the MnDRIVE Environment Initiative, doctoral candidate Laura Bender harnesses the power of soil fungi to help plants absorb pollutants.

by Kyle Wong

To ensure a healthy crop, Minnesota farmers carefully track soil health, nutrients and the quantity of water flowing through their fields. Since 2015, Minnesota’s Buffer Law also requires farmers to tend to historically overlooked land along the edge of these fields. The law mandates a 50-foot buffer along farm fields bordering public waterways, including irrigation and drainage ditches, to help reduce contamination from farm runoff. Instead of corn, soybean and other cash crops, buffer zones are full of perennial plants and trees adept at absorbing excess nutrients flowing from the fields. With financial assistance through environmental programs like the federal Conservation Reserve Program, farmers have both the mandate and the incentives to establish quality buffers. 

Like their commercial counterparts, plants in buffer zones naturally take up nutrients, but researchers like graduate student Laura Bender, hope to improve the process by focusing on fungi living beneath the soil. Soil fungi colonize the roots of buffer plants to form a symbiotic, or mutually beneficial, relationship. “These relationships help plants take up pollutants that would otherwise escape to the waterways, but soils are often degraded through decades of tillage and fertilizer application and compaction,” Bender notes. “The fungi communities that are naturally present in soil are often degraded or absent.” Supported by a 2018 MnDrive Environment seed grant, Bender works to restore those fungal communities to strengthen buffer plants and keep Minnesota waters clean. 

Bender works with several companies working with fungal amendments and measuring techniques. MycoBloom, for example, developed a fungal amendment containing a type of fungus called  arbuscular mycorrhizal (AM). AM fungi have been shown to help plants absorb nutrients more efficiently. But soil types vary across Minnesota, so Bender has worked with farmer Dave Legvold to test the amendment on the buffer zones on his farm. She collects data from his testing site each year to identify how well the amendment might work in the rest of Minnesota.

Bender collects soil and plant samples from the field site’s buffer zone and measures the level of phosphorus, one of the most common farm nutrients harmful to waterways. Alongside the buffer, she also collects dissolved groundwater. The Research Analytics Lab at the University of Minnesota processes the soil, plant and groundwater samples to calculate the phosphorus levels in each component. Bender uses the data to trace the amount of phosphorus that the buffer plants absorb and the amount that escapes to the water. “We’re measuring how the phosphorus level changes each year to see if the fungi amendment is removing it from runoff water that enters the buffer,” she says.

Phosphorus levels in the buffer are only part of the story; Bender wants to observe the interactions between the AM fungi and the buffer plants. To do so, she needs to look below the soil and analyze the mycorrhizal interactions at a microscopic level. Here, she partners with the company MycoRoots to assess how well the AM fungi colonize the roots of buffer plants. MycoRoots documents the surface area of plant roots covered by AM fungi. Bender uses the data to understand the role that mycorrhizal association plays in phosphorus uptake. Data from 2018 and 2019 revealed that plants with high root coverage from AM fungi tended to take up more phosphorus, leading to lower phosphorus levels in both the soil and groundwater. Bender will conduct more data analysis this fall before forming a conclusion. 

Ultimately, Bender hopes to guide state policy to help farmers understand the best practices for their buffers. To build awareness, Bender plans to lead an online workshop this fall to bring farmers, policymakers and industry partners together for a discussion on buffer-related issues and policies. “It’ll be related to specific topics – different fungi people have used, success or failures in certain settings, opportunities for collaboration, etc. The goal is to identify where others have used amendments and how it has worked for them.” 

With additional funding from MnDRIVE Environment and the University’s Institute on the Environment, Bender hopes to continue research and strengthen her partnerships with the community. Proper guidelines on buffer strips and fungal amendments can help Minnesota landowners establish healthy buffers that benefit them financially and help conserve the environment.

This research was supported by MnDRIVE Advancing Industry, Conserving Our Environment at the University of Minnesota.

Kyle Wong is a writing intern in the University of Minnesota Science Communications Lab, majoring in Microbiology. He can be reached at wong0511@umn.edu

An End in Sight For “Forever Chemicals”

An End in Sight For “Forever Chemicals”

MnDRIVE researchers Mikael Elias and Lawrence Wackett are studying Acidimicrobium in hopes of harnessing the bacteria’s PFAS-degrading power.

By Caroline Frischmon

Waterproof, nonstick and flame retardant. Products like raincoats, frying pans and firefighting foam keep us safe, clean and comfortable. Their durability stems from the presence of carbon-fluorine bonds, which are some of the strongest in organic chemistry. Unexpectedly, these great modern conveniences have also created a widespread environmental problem. Compounds with multiple carbon-fluorine bonds, called PFAS (perfluoroalkyl substances), have accumulated for decades in the environment with no effective way to break down these “forever chemicals.” 

Exposure to PFAS through drinking water is associated with higher cholesterol, certain cancers and suppressed immune responses. Scientists and regulators have tried to address the PFAS contamination through filtering, coagulating, burning and more, but most cost-effective solutions simply concentrate the chemicals and move them away from wells, aquifers and other points of human contact. Now, there’s hope that a bacteria called Acidimicrobium sp. might hold the key to a more permanent solution. Through a MnDRIVE Environment Seed Grant, researchers Mikael Elias and Lawrence Wackett, both University of Minnesota professors in the Department of Biochemistry, Molecular Biology, and Biophysics, will study the bacteria’s promising ability to digest PFAS.

Last year, researchers at Princeton University discovered Acidimicrobium could digest PFAS chemicals and convert them to carbon dioxide and fluoride. It’s the first identified bacteria that actually breaks the carbon-fluorine bond, but scientists are wary of calling it a solution quite yet. The microbes eat too slowly on their own to be effective at the scale needed to address PFAS contamination in the environment. To speed up the process, Elias and Wackett will first need to identify the enzymes that give Acidimicrobium its superpower.

All living things use enzymes, or biological catalysts, to accelerate chemical reactions. They are highly specific to one job, whether it’s digesting fats or sugars or assisting in DNA production. Out of all Acidimicrobium’s enzymes, scientists aren’t sure which ones are responsible for the PFAS reaction. “What we’re really going after now is to identify and characterize the actual enzymes responsible for the degradation process,” states Elias. That understanding will pave the way for improving their efficiency through genetic modification. Eventually, the team hopes to develop the enzymes as a PFAS bioremediation tool.

Wackett and Elias partnered on this project to share their varying expertise. Wackett, an enzymologist, will analyze the bacteria’s DNA sequence to identify which enzymes are likely responsible for PFAS degradation. Elias, a structural biologist, will determine how the structure of Wackett’s enzymes facilitates the reaction. 

Using 3D images to reveal the structure of the enzyme’s active site, Elias examines the arrangement of amino acids, the building blocks of enzymes. “We’re going to look at how the amino acids in the enzyme break down the PFAS molecules,” explains Elias. With that information in hand, he and Wackett will try to engineer better enzymes by manipulating the arrangement of the amino acids.

 In addition to engineering a more efficient Acidimicrobium enzyme, Wackett and Elias will search for other potential PFAS-degraders with related DNA sequences. Bacteria with similar enzymes as Acidimicrobium might digest PFAS even more efficiently, but scientists haven’t been able to test for them yet. “When we have the sequence code, we will know how to look for the enzymes and the genes in other bacteria,” says Wackett, “That’s another big advantage of having the structure and knowing those key amino acids.”

Existing PFAS technologies focus on sequestration rather than degradation. “[Containment] is useful until you have a better solution, but it’s imperfect because it has limited capacity,” Elias points out. “You’re just moving pollutants from one place to another.” The MnDRIVE seed grant provides an opportunity for a better solution. Elias and Wackett hope Acidimicrobium will help them finally eliminate these forever chemicals for good.

This research was supported by MnDRIVE Advancing Industry, Conserving Our Environment at the University of Minnesota.

Caroline Frischmon is a Science Communication Fellow in the Science Communications Lab and is majoring in Bioproducts and Biosystems Engineering. She can be reached at frisc109@umn.edu.

 

Clean Energy from Beer Waste?

Clean Energy from Beer Waste?

MnDRIVE-funded researcher harvests natural gas from brewery wastewater

By Nick Minor

From industry pioneers like St. Paul’s Summit Brewery to small-town brewpubs, Minnesota’s craft beer industry has become a point of pride for local beer enthusiasts. But for every pint that flows through the tap, 3 to 10 pints of wastewater–high in carbohydrates, acids, and alcohol–end up in the municipal waste stream to be treated by the city. Breweries pay a premium to remove and treat this wastewater. Still, that same nutrient-rich content provides an ideal food source for hungry microbes capable of turning the waste into energy at the brewery.

With funding from the University of Minnesota MnDRIVE Environment Initiative, researchers led by Professor Paige Novak set out to treat this brewery wastewater while achieving two additional benefits: reducing the load on municipal water treatment systems and producing energy to help fuel brewery operations. 

Kuang Zhu, a recent PhD graduate from Novak’s lab, designed a 2-stage process to treat the brewery wastewater. In the first stage, microbes (called acetogens) feed on the wastewater. Housed in an airtight, oxygen-free compartment, they digest the carbohydrates in the wastewater, producing hydrogen and acetate as byproducts. These byproducts are then siphoned into a second oxygen-free compartment where microbes (called methanogens) consume the acetate, and produce methane, a significant component of natural gas. One of the team’s original innovations was to house the microbes in beads made of a carbohydrate derived from brown algae. This keeps the active microbes in the reactors where they can do their work simply and with little energy expenditure. Hydrogen collected from the first stage, and methane collected from the second can be used to generate power for the brewery while the treated water, significantly cleaner, flows to the local municipal wastewater treatment facility.

Scaling up this research from the lab to the brewery, presented its own set of challenges. Partnering with Fulton Brewing in Minneapolis, the team embarked on “months and months of troubleshooting,” Novak recalls. There were constant tweaks, leaks, and spills; parts to replace, cross-contamination, and even a small wastewater “explosion,” all within a wastewater storage room that averaged a steamy 85 degrees Fahrenheit. 

But this process, slow and tedious though it may be, is a critical part of science. Novak credits the demonstration grant from MnDRIVE, a state-funded initiative that aims to connect basic research with real-world impacts, for making this possible. “It’s such a different kind of trial and error and troubleshooting process,” explains Novak, “and there are so few funding sources for that kind of work. Going through this demonstration project has been invaluable because we figured out all those things we need to pay attention to when we do this again.” 

“Plus,” Novak adds, “it’s been really fun.”

One part of that fun is a public art exhibit that was stimulated by a requirement of MnDRIVE grants to have a public outreach component. After meeting local artist Aaron Dysart at a conference, Novak knew his data-driven approach to art would be a perfect fit for her project and for making the required outreach component much more visible. Dysart plans to create a disco ball suspended outside the Fulton taproom. Not just any disco ball, Dysart’s installation will spin at a rate proportional to the gas produced by the bioreactors. It will project color sequences linked to the ratio of hydrogen and methane. Mounted sideways, Dysart’s disco ball project will be a stream of data bubbling up from the wall of the brewery’s outdoor beer garden.

Of course, getting the bioreactor design into the real world won’t just involve science and engineering. It also requires understanding how the bioreactor fits into the marketplace. Again, thanks to MnDRIVE funding, Novak was able to partner with the Carlson School of Business to conduct some preliminary market research. “They analyzed the technology and the market,” Novak says, “and evaluated different food and beverage industries that would be a good match for our technology.” To Novak’s surprise, Carlson’s research showed that breweries weren’t the only market for the bioreactor. “Breweries don’t typically spend enough money [for this to make a big difference for them].” Instead, potato chip makers and candy manufacturers, both of which generate high concentration wastewaters, could benefit more from the team’s design. Furthermore, the business school team clearly showed that before the technology will be accepted by industries, the design must be plug and play and ready to work out of the box, regardless of the nature of the waste stream.

This goal is now much closer to reality thanks to progress made through the demonstration grant. One day, Novak hopes high concentration industrial wastewater treatment will be as simple as “getting your beads, dumping them in, and watching them go to work no matter what.” MnDRIVE funding not only helped move the technology forward, it also allowed the team to identify industries most likely to benefit from the research and provided an opportunity for consumers to learn about wastewater treatment through a public art installation.            

Nick Minor is an alumnus of the Science Communications Lab, pursuing a master’s degree in zoology and physiology at the University of Wyoming. He can be reached at minor092@umn.edu.