Circular CEA System Takes the Stage During Univ. of Arizona Short Course
April 15, 2025 Circularity in CEA was the focus of a full day’s worth of sessions at the recent Greenhouse Engineering Design & Crop Production Short Course, held at the University of Arizona’s Controlled Environment Agriculture Center (UA-CEAC) March 26-28. Getting into practical applications, one session detailed research being done with mushrooms, leafy greens, fish, and beetles for a nearly-closed-loop, modular, and mobile circular CEA system.
Goggy Davidowitz, Ph.D., a professor in Arizona’s department of entomology, explained that just like plants, mushrooms, and fish, edible insects can be grown in controlled environments. The research—a collaborative, multidisciplinary initiative at UA-CEAC—is testing the potential for a circular food system in which all four of these “crops” are grown together.
“It’s almost a complete ecosystem,” he said.
How it Works
“Every living organism, whether it’s bacteria, a tomato, or an elephant, requires inputs of resources and has outputs of waste products,” Davidowitz said. In CEA, you can create circularity in systems where, say, mushrooms are grown in tandem with plants. (Mushrooms’ CO2 output becomes input to help the plants grow better, while the plant environment provides excess water to support high levels of humidity for optimal mushroom growth.)
Aquaponics is another circular opportunity, in which fish are grown in tanks in concert with leafy greens—the fish offering nutrients to the plants via their waste (which is first broken down into nitrates by bacteria), and the plants naturally cleaning the water, which is returned to the fish tanks.
The UA-CEAC research looks at combining these two examples with the farming of insects as a potential food source for the fish. Taking circularity even further, the team is incorporating a sustainable element to feed the insects: “boutique compost” made from a combination of produce food waste and spent mushroom substrate (organic materials left over from mushroom harvesting).
Why Edible Insects?
The insect component of this CEA process, Davidowitz said, comes into play because fish meal—a key ingredient of aquafeed that’s made from ground-up types of fish that humans don’t want—now comprises 80% of the cost of growing fish via aquaculture (due to overfishing). The aquaculture industry, looking for alternatives to fish meal, has increasingly turned to high-protein insects as an option. The benefit of insects as feed for aquaponics operations is particularly compelling, as they provide more plant-friendly nutrients than fish meal.
Fruits, vegetables, and mushroom module harvests are being dried on site via a solar drying tower (pictured here) built by the team at the CEAC. | Photo: The University of Arizona
Davidowitz and the team are studying 12 types of insects that could potentially be grown as feed for their circular CEA system; for this presentation, he focused on the green fig beetle, an insect common to the region during the summer and—they believe—capable of providing highly beneficial outputs for both plants and fish.
To feed the beetles, the research team is creating its own compost. Fruits and veggies that would otherwise go to a local landfill are being dried on site via a solar drying tower built by the team. Likewise for what’s left over after the university’s mushroom module harvests. The resulting shelf-stable composts are blended and studied in different ratios to determine the best mix for maximum benefits.
In a MISAS system, mushrooms, plants, fish, and/or insects are all grown in their own container farms. | Photo: The University of Arizona
The MISAS System Model
Bringing all these elements together creates what the research team is calling MISAS: a Modular, Integrated, Sustainable Agriculture System. Each crop—mushrooms, plants, fish, and/or insects—is grown in its own container farm, which could then be transported and configurated to work as a system in various locations.
Davidowitz said the hope is that communities could custom-design a MISAS to fit their needs through a centralized website, whether they’re a large urban area with tight land constraints, a food desert in a remote area, or any other scenario.
“Local communities could start producing food almost immediately,” he said.
In-person attendees at the UA-CEAC short course were able to tour the MISAS research modules, as well as the university’s mushroom lab, teaching greenhouses, and aquaponics facilities.
UA-CEAC is celebrating its 25th anniversary this year; this was the 24th year of the short course. To learn more about the school’s CEA program, visit ceac.arizona.edu.