UMN researchers bring back microbes from Japan for water treatment in Minnesota

by Deirdre Manion-Fischer

Manganese is an essential micronutrient present in Minnesota’s groundwater, but in some areas, especially the southwestern part of the state, manganese levels are high enough to raise health concerns. Over time, at high concentrations, the metal can accumulate in the brain and result in neurological conditions among older adults. “There’s no cost-effective technology for removing manganese and other pollutants such as sulfate from our waterways,” says Satoshi Ishii, an associate professor in the Department of Soil, Water, and Climate and a member of the University’s BioTechnology Institute (BTI). Instead, Ishii and fellow BTI member Cara Santelli, a geomicrobiologist and assistant professor in the Department of Earth Sciences turned to bioremediation to solve the problem.

Bioremediation uses microorganisms to break down harmful chemicals in water and soils. Ishii identified the microbe capable of removing manganese from water in Onneto Yu-no- taki falls, a waterfall in his native Japan. The falls contained high levels of manganese and sulfate, and as Ishii suspected, high levels of manganese-oxidizing microorganisms.

Emily Anderson, a graduate student in Ishii’s lab recently built a lab-scale bioreactor to house the manganese-oxidizing microorganisms. “I’m really interested in using living systems to clean water, especially when we don’t have the resources to do it in other ways.”

The bioreactor mimics the environment in the Onneto Yu-no- taki falls waterfall where a biofilm made up of microorganisms coats the streambed, and rocks covered in manganese oxides appear to have turned black. In the bioreactor, water flows through three consecutive rectangular compartments made of transparent plastic. In each compartment, microorganisms oxidize manganese and remove it from the solution. The bacteria, fungi, and algae form mats coating the sides of the compartments and algae serve as a food source for the manganese-oxidizing microorganisms. Over time, you can see tanks turn from green to black as the manganese oxides build.

Anderson tracks manganese oxidation by sampling the water and how much dissolved manganese was removed by the biological activity. She was surprised by how fast the oxidation occurred. The bioreactor removed all the dissolved manganese in a couple of hours.

Santelli and Ishii plan to optimize the process and refine the bioreactor’s design to determine which organisms are most efficient at oxidizing manganese. So far, Anderson has identified 60 different manganese-oxidizing microorganisms in the sediment samples Ishii brought back, and with the manganese oxidation working, the plan is to incorporate sulfate removal as well. Where
manganese is found in high amounts, sulfate is often present as well. It’s a particular concern in Northern Minnesota where bacteria in the subsoil transform sulfate into sulfide, which can inhibit the growth of wild rice.

The MnDRIVE team partnered with Barr Engineering, an environmental consulting company with headquarters in Minneapolis. Barr helped design a bioreactor that could be easily scaled up and will also help the team identify manganese and sulfate contaminated sites in Minnesota. Eventually, industrial-scale bioreactors could be used in water treatment facilities, and provide a cost-effective, sustainable solution to one of the state’s enduring environmental challenges.

UMN researchers investigate nutrient recycling to mitigate the impact of agricultural runoff and carbon emissions.

By Rachel Zussman

Minnesota is an agricultural powerhouse that ranks 5th in the nation for total agricultural production. However, this agricultural prosperity may inadvertently threaten the future of the state’s 10,000+ lakes. Agricultural runoff, often high in inorganic nitrogen and phosphorous, can fuel the rapid growth of algae that deplete lakes and streams of oxygen. This process known as eutrophication threatens the structure and function of entire aquatic ecosystems and has been linked to dead zones as far downstream as the Gulf of Mexico.

Robert Gardner, a professor of Bioproducts and Biosystems Engineering at the University of Minnesota West Central Research and Outreach Center, hopes to capture and recycle the nutrients in runoff water and produce an environmentally friendly microalgae-based biofertilizer. Gardner’s research funded in part by a MnDRIVE Environment seed grant could reduce demand for synthetic fertilizer while boosting farm productivity and sustainability.

Nitrogen and phosphorus, Gardner points out, are not inherently bad. Plants require both to grow and thrive, but synthetic fertilizers tend to oversaturate crops with nutrients, so the excess seeps into the runoff and eventually into lakes and streams.

The microalgae-based fertilizer proposed by Gardner eliminates this issue by releasing organic nutrients at a much slower rate. “We are capturing, converting, and recycling the inorganic nitrogen and phosphorous found in runoff water into an organic form,” says Gardner. Instead of seeping into the runoff, nutrients remain in the field and are released slowly as the algae decompose.

To simulate a natural rain event and the resulting runoff, Gardner’s team utilizes a three-story water drop tower housed within the USDA-ARS North Central Soil Conservation Research Lab. The water is collected and analyzed for its nitrogen and phosphorous content. The team then cultivates the microalgae using nitrogen and phosphorous found in the runoff and carbon dioxide supplied by the project’s industry partner, Chippewa Valley Ethanol Company. Once harvested, the algae can be applied to crops as a biofertilizer.

Gardner is currently working to optimize the microalgae for specific crops and environmental conditions. “Similar to crop rotation, we must grow different microalgae strains at different times of the year,” explains Gardner. Different strains may be applied in early spring or midsummer in response to changes in temperature and rain patterns. To make matters more complex, many plants use nitrogen at a faster rate than phosphorous. Even if nitrogen is eliminated from the runoff water, there may still be residual phosphorous. To address this issue, Gardner is currently exploring the rate at which differing algal strains take up the nutrients to optimize the system for different crops and field conditions.

In the lab, Gardner’s team is at work characterizing and optimizing algal strains and running simulations to establish best practices for deploying biofertilizers. Though still in the demonstration phase, the research shows promise for future broad-scale application. “Fertilizer is a precious commodity. If we are able to make it more sustainable while also increasing its capability,” explains Gardner, “it will help feed our future and save our lakes.”

Industrial Partners

Located in Benson, Minnesota, the Chippewa Valley Ethanol Company (CVEC) is the industrial partner for Gardner’s MnDRIVE project. By participating in the project, the company can recycle excess carbon that would typically go straight into the atmosphere. In addition to reducing its environmental footprint, the company would be able to avoid a carbon tax should it become a reality. CVEC will also provide knowledge and structural support necessary to take the project to production scale. “These grand challenges take a team, and the Chippewa Valley Ethanol Company is an essential part of our team,” says Gardner.

Rachel Zussman is a Biology, Society, and Environment major at the University of Minnesota’s College of Liberal Arts and an intern in the BioTechnology Institute’s Science Communications Training Program.

MnDRIVE investigators are developing distributed wastewater treatments that transform carbon waste into clean electricity.

by Colleen Smith

Microbreweries are on the rise in Minnesota — as is the wastewater they produce. While many have come to appreciate the rich diversity these venues offer, most remain unaware of the waste per pint produced. Researchers at the BioTechnology Institute (BTI), however, are designing new strategies for purifying and transforming on-site waste into on-site electricity.

“Food-based industries are responsible for a lot of the carbon load discharged to our Metropolitan wastewater treatment plant,” says Paige Novak, an environmental microbiologist, engineer, and BTI faculty member in the Department of Civil, Environmental, and Geo-Engineering. As currently treated, this carbon-rich wastewater results in huge energy demands when it reaches the treatment plant.

Local food-based industries like dairy, sugar beet and beer routinely produce large quantities of carbon-rich wastewater. According to the Brewers Association, brewing one pint generates seven pints of wastewater on average. While some larger craft brewers can cut that figure down to only a couple of pints, others (typically microbreweries) sometimes produce as much as 15-20 pints of waste per pint of beer.

Currently, there are no cheap and easy ways to treat carbon waste on-site. Therefore, most businesses simply adjust the pH and dump it down the drain. Downstream at treatment facilities, however, the massive resources committed to purifying wastewater churn out greenhouse gas emissions. In response, the largest contributing industries are annually slapped with charges for waste treatment.

The good news is that Minnesota regulators are investing in promising new techniques to address these problems.  In addition to an infusion of MnDRIVE research funding at the University of Minnesota, the Metropolitan Council of Environmental Services (MCES) has initiated a first-of-its-kind program of financial incentives for industries to clean up their own waste and keep it from ever reaching centralized treatment facilities. This idea of distributed wastewater treatment is catching on, but there’s a lot of work to do before researchers have hammered out how such systems could be practically implemented.

Novak’s idea is to develop bioreactors that enable finely-tuned microbial populations to eat excess carbon directly out of wastewater. As it turns out, the high concentration of carbon in beer wastewater is ideal for the specialized microbes she studies. In her research, she uses wastewater samples directly from Fulton Brewery in Downtown Minneapolis to develop and test new tech.

“Some of the microbes I study produce hydrogen as a byproduct,” says Novak. “Their other products can be eaten by different microbes that make methane from it.” The resulting gaseous combo could be used as a clean, combustible fuel to produce electricity on-site — but there must also be an efficient way of collecting the gas.

Novak is therefore collaborating with environmental and mechanical engineers to develop a hollow, sheet-like material. Microbes are encapsulated in the wet outside layer of this material and emit gas into its dry, hollow center. The gas can be siphoned out and used to turn motors that generate electricity. Novak envisions that sheets of this material could be folded into cassettes and inserted into existing waste tankage on-site — first at breweries, and eventually in other industrial settings.

Aunica Kane, a post-doctoral BTI researcher working with Daniel Bond and Jeffrey Gralnick, BTI faculty members in the Department of Microbiology & Immunology, approaches the same problem of using microbes to clean wastewater, albeit with a different strategy. Kane studies bacterial populations that respire onto metallic surfaces. That is, rather than using oxygen to breathe, these bacteria breathe insoluble metals.

BTI researchers look to replicate plant disease suppression by understanding microbial communities in the soil.

by Sarah Perdue

Crop loss due to disease is a major factor in the use of pesticides, but current BTI research is hoping to decrease pesticide use while also increasing crop yields. “We know that some soils are more disease suppressive than others, and the same crops grown in disease suppressive soil are healthier than those grown in normal soil,” said Zewei Song, a postdoctoral fellow in plant pathology. His work, which could lead to less pesticide runoff from farmland into lakes and streams, is funded in part by a MnDRIVE: Environment postdoctoral fellowship. “What is more amazing is you can inoculate this disease suppressive soil into sterile soil and this soil becomes disease suppressive,” Song added, likening this process to microbiota/fecal transplantation in humans, also being studied at the University. “We want to find the biological mechanisms that make soils disease suppressive and reproduce this outcome in agricultural fields.”

Researchers have long known that competition amongst microbes plays an important role in antibiotic production and plant health, but studies have often focused on one species at a time, or interactions between only a few species. Song and his colleagues want to study the systems of soil microbes as a whole to better understand how their interactions lead to plant disease suppression. If they can understand how soil microbes suppress plant disease, then they can more quickly mitigate the effects of crop pathogens. “We’re adding carbon sources into the soil to increase competition, then we’re measuring plant disease, such as scab on potatoes, and sequencing the microbial communities to identify their structure,” Song said. “We’re trying to see if we can increase disease suppression with these carbon additions and understand the responses in the microbial community structure over time.” Linda Kinkel, Professor of Plant Pathology and lead investigator of the study, said the field study is in its second season so the microbial community structure changes have not yet been analyzed. “We saw good responses in terms of reductions in disease and enhancements in plant productivity during the first season of the study,” she added.

Kinkel said that this project builds on a USDA-funded project, but without MnDRIVE they would only have had funding to investigate the effects of carbon amendments on the plants. “The USDA study allows us to measure the plant response to the treatments, but MnDRIVE provides the funds to collect data on shifts in soil community composition and diversity following treatment,” Kinkel said. “There’s synergy there. The whole really is greater than the sum of the parts.” Kinkel added that Scott Bates, former Assistant Professor in Plant Pathology and partner on the project, has contributed significant expertise to the analyses of the fungal communities in the treated plots. Song noted that increasing crop yields could do more than simply add to the food supply. It could also lead to more efficient alternative energy production. “In a shift to more biofuel production, the Department of Energy requires you to grow biofuel crops that don’t compete with traditional crops,” he said. “If you can reduce crop loss before harvest, then you can produce both food and biofuel without compromising either.”

MnDRIVE sponsored research from civil, environmental, and geo-engineering Professors Paige Novak (BTI) and Bill Arnold and post doctoral researcher David Tan (BTI) is featured on the cover of a prominent environmental journal. These researchers are studying how to transform one of the major sources of pollution from artificial hormones. Their research demonstrates evidence of ways to improve the selection and activity of bacteria that can degrade estrone in water sources.

Read the article in the journal Environmental Science Water Research & Technology

This story first appeared on the homepage of the University of Minnesota Department of Civil, Environmental and Geo-Engineering

MnDRIVE researcher looks to Minnesota’s Iron Range for microbial components of sulfide mineral oxidation and sulfate remediation.

by Sarah Perdue

For Dan Jones, a research associate in the BioTechnology Institute and the Department of Earth Sciences, biogeochemistry is not simply an important field of research — it literally rocks.

Jones, who is funded through MnDRIVE: Advancing Industry, Conserving Our Environment (MnDRIVE: Environment), studies natural rock formations and their associated microbial communities. His work, which includes basic science, fieldwork, and industrial applications is focused on microbial processes related to sulfide mineral oxidation in the Duluth Complex — a huge rock body that holds one of the largest undeveloped sources of copper, nickel, and platinum group elements in the world. It is also under review as a potential mining site.

“If you dig up that rock, expose it to oxygen, and nothing is done to contain drainage, it could produce problems such as acidic drainage or sulfate contamination,” Jones said.

Because the Duluth Complex has never been mined for metals, potential contaminants and their concentrations need to be determined experimentally. Through the Minnesota Department of Natural Resources (DNR), Jones obtained rock samples from the Duluth Complex that have been weathered in the lab for over a decade, in effect mimicking their exposure on the Earth’s surface. Working with MnDRIVE co-directors Paige Novak and Mike Sadowsky, and Earth Sciences assistant professor Jake Bailey. Jones uses the samples to understand the associated microbial communities and processes.

“The end goal for me is to understand which microbes are there and what role they play in sulfide mineral oxidation,” Jones said. “The end goal for the DNR and the companies proposing to mine the Duluth Complex is to understand what types of metals, acids, and contaminants are going to be released from this rock and what to do about it.”

Jones is also part of a research team working on a MnDRIVE-funded bioreactor designed for cost-effective sulfate removal. The team, which includes Sadowsky and BTI research associate Chan Lan Chun is partnering with researchers at the Natural Resources Research Institute at UM-Duluth, along with Clearwater Layline LLC, a small Minnesota-based water technology company.

“In Minnesota we have a strict sulfate standard because it is detrimental to wild rice,” Jones said. “Sulfate is just a challenge to remove from water, so one of the best ways to remove it is to biologically reduce it and immobilize it as an iron sulfide mineral.”

Cost and efficiency are limiting factors, so Jones and UM-Duluth colleagues Nathan Johnson and Adrian Hanson also recently proposed research to improve the process. They want to investigate cheap sources of carbon, like waste from paper mills or water treatment facilities, to feed the microbes. They are also looking at low-cost sources of iron (like mine tailings) required to immobilize the sulfur.

“They’re not juicy, nutritionally-rich sources, but they’re cheap,” Jones said.

In addition to his research role, Jones is the industrial liaison for MnDRIVE Environmental initiative. His role is to organize meetings and connect the relevant professionals, with the expectation that once an environmental concern has been identified in one sector of the economy, MnDRIVE-funded research can help to reduce the impacts.

“The goal is to bring microbiologists, geologists, engineers, mining engineers, and regulatory people together to bridge the gaps, get people talking, understand the issues, and figure out what we can do about them,” Jones said.

While the current focus is primarily mining, Jones expects MnDRIVE to play a role in other areas where economic activity and environmental concern overlap.