What’s in it for you?

WINTER 2025-26 Inventing tomorrow

Engineering breakthroughs and basic scientific principles matter. These five stories show how discoveries—like pollution-eating bacteria—shape life

By Joel Hoekstra

Across the University of Minnesota College of Science and Engineering, curiosity results in fresh ideas that can solve problems.

If you like clean water, raise a glass to environmental engineering professor Paige Novak the next time you drink beer. Her ongoing effort to use encapsulated bacteria to treat wastewater is helping one Minneapolis brewery reduce its waste streams—and the concept could someday be applied to candy-making and dairy-processing facilities, as well as other breweries.

Professor Paige Novak (right) is encapsulating active bacteria in polymer beads to treat wastewater. Ph.D. student Kendall Johnson ran a pilot study with Fulton brewery. Photo by Erin Brenner.

Wastewater is a huge byproduct of brewing, generating four to 10 pints of wastewater for every pint that’s produced. Large operations often opt to treat that wastewater onsite, but most smaller breweries must pay a fee to have the dregs processed at the local sewage-treatment plant, where air and microorganisms are pumped through the wastewater to clean it.

That process requires massive amounts of energy, with roughly two percent of all U.S. electricity consumption devoted to wastewater treatment. Novak has long been interested in finding ways to use bacteria to treat environmental problems.

“When I was a kid, I remember hearing a story on the radio about scientists using bacteria to clean up an oil spill in the Gulf of Mexico,” she said. “I thought that sounded so cool.”

In 2013, Novak and UMN chemist and environmental engineer Bill Arnold approached Fulton Beer, a Minneapolis microbrewery, with a novel idea. They had been experimenting with encapsulating active bacteria in polymer beads that would degrade contaminants in wastewater. The bacteria would effectively treat the wastewater onsite, reducing the amount of discharge sent to the wastewater processing plant as well as the associated costs.

Discovering a new energy source is one unanticipated benefit of this pilot project. Methane, a greenhouse gas produced as bacteria break down wastewater, can be captured and burned to heat space or potentially even power operations.

“Our collaborative work with Fulton has shown that if these encapsulated biomaterials were scaled up, it would result in energy cost savings,” said Novak.

Her team is working to scale up manufacturing to further test this finding. The researchers are also thinking of ways to manipulate the bacteria’s lifecycle. If they can control when the bacteria dies, they can begin to target other pollutants for resource recovery.

Could custom 3D printing save your life?

Professor Michael McAlpine is pushing the boundaries with 3D-printed bionics

Inventors have long sought ways to fuse human biology and mechanical engineering to improve the human condition. Devices ranging from hearing aids to cardiac pacemakers have benefited thousands, if not millions of people. But such implants fall somewhat short of the cyborg-like integration depicted in shows like “The Six Million Dollar Man.”

True bionics blend both biology and technology—and Mechanical Engineering Professor Mike McAlpine has found a way to do just that, overcoming one of the biggest challenges in bionics: interweaving electronics with three-dimensional bioengineered structures into human tissue. In 2013, he used a custom 3D printer to create a human ear.

Illustration of a body with various parts highlighted

“We cultured cells and then printed on necessary electronics as one integrated object, with the technology embedded in the cartilage tissue,” he said. “Tests showed that it can match normal human hearing.”

Since then, McAlpine and his research team have experimented with 3D-printed bionic eyes and 3D-printed scaffolding that supports the growth of spinal cord cells—a collaboration with UMN spinal cord injury expert Ann Parr. McAlpine’s work has potential implications for a broad range of biomedical devices, wearable electronics, bioelectronics, smart prosthetics, regenerative medicine, and human-machine interfaces.

“Things that would typically be produced in a cleanroom can be done entirely with a 3D printer,” McAlpine noted, greatly simplifying their creation.

The biggest challenge, he said, is achieving seamless integration of the nanotechnology and biological materials used to create bionic devices. Most of the materials that comprise conventional electronics are two-dimensional, hard and brittle, and require high temperatures to crystallize. Typically, these traits are incompatible with tissues and other biological materials, which are three-dimensional, soft, stretchable, and temperature-sensitive.

McAlpine’s work has drawn interest from a wide range of organizations, including for-profit companies, nonprofits, the National Institutes of Health, and the U.S. Army. The seemingly limitless applications are exciting to the researcher.

“Helping people and expanding human knowledge and capabilities should be the end goal of any scientific project,” McAlpine said.

—by Joel Hoekstra

A man juggles 3 black and white balls outside on a green lawn

WHAT DO JUGGLING AND FAIRNESS

For Nick Arnosti, it’s all about patterns—how data can help us share public goods more equitably

By Joel Hoekstra

Nick Arnosti wants to help you win the lottery—but some caveats apply.

For starters, the lotteries that this University of Minnesota industrial and systems engineering associate professor studies don’t award money, but rather housing and public school opportunities, immigration visas, as well as hunting licenses, hiking permits, and discounted event tickets. And by win he means helping as many people as possible get their preferred outcome.

“Lotteries for public resources are interesting to me because they’re a really nice combination of elegant math and its application to real-world problems,” Arnosti said.

But the lotteries don’t always work as intended. In New York City, where affordable housing is hard to find, developers list upcoming affordable housing opportunities on a city-run website. Potential renters can create profiles on the site and indicate their interest in various properties in the hopes that they will eventually be matched with a top choice.

Such lotteries may seem preferable to traditional waiting lists, where applicants are given only one offer (and move to the back of the line if they reject it). But in New York’s lottery system, desperate users are likely to apply for any building better than their current situation.

Arnosti’s work shows that the end result is no better than using a waiting list: users have little say in where they are placed, and many are assigned to housing that may not meet their criteria.

“One reason that inefficient systems persist is that we don’t have a way to measure whether a system is working,” Arnosti said. “To know if you’re doing well, you have to have the right metric.”

Arnosti is currently working with NYU’s Furman Center to advise city housing officials on ways to offer successful lottery applicants.