Large-scale dairy operations send immense quantities of whey into the waste stream, but Costas Katsimpouras and DIWAV are engineering a process to convert that dairy industry byproduct into high-value carotenoids that a range of industries depend on.

Costas Katsimpouras knows his Greek yogurt. 

“It was a staple,” says the MIT research scientist, who grew up in Greece. “You have to add honey, always.”

The yogurt he enjoyed growing up, however, has little to do with the stuff at the supermarket—which produces significant amounts of waste material. 

“Homemade Greek yogurt isn’t as thick as store-bought because we can’t concentrate it that much,” Katsimpouras says. “So the industrial scale creates more acid whey.”

Acid whey is where Katsimpouras’ current research interests lie, funded by Schmidt Sciences’ Virtual Institute on Feedstocks of the Future (VIFF). As a member of the Dairy Industry Waste Valorization (DiWAVE) project, Katsimpouras and his team is exploring how whey and other biomass can be diverted from the landfill and transformed into everything from cosmetics to fish food to fuel.

The key ingredient to create from whey: carotenoids. 

“They’re called that because they mainly exist in carrots,” Katsimpouras says of the compounds, also found in flowers. “They are natural colorants and powerful antioxidants.”

While carrots and other carotenoid producers tend to create only small amounts, and require significant inputs in terms of arable land and fresh water, DiWAVE is working to create a microbial synthesis process at large scale.

Carotenoids have a variety of applications, Katsimpouras notes. Clinical trials have shown that they decrease the risk of macular degeneration, and they’re also frequently used in sunblock as betacarotene. Carotenoids can also appear in animal feed as replacements for synthetic dyes, used to give farmed salmon their pinkish tinge and to ensure the orange-yellow hue of egg yolks. 

“It matters for consumers—they think something is wrong if salmon is white—but they also prefer natural products,” Katsimpouras says. “Right now 95% of the market in aquaculture is synthetic.

The recycling of wasted whey into a powerful ingredient is a win-win. “By developing all these technologies that take advantage of feedstocks,” he says, “we can create new market opportunity, create more jobs and help communities.”

In the first year of the project, Katsimpouras and his team researched the feedstock itself—what types of milk, processes and products generate which types of whey. “This guides our engineering process,” he says. “When we have different profiles of feedstock, we need to know how to use it and get the same result at the end.” 

Then, the team was able to convert the feedstock and separate the useful carotenoids from the rest. “We expect a good yield,” Katsimpouras says. 

Alongside the scientific research, VIFF has provided the researchers with community and networks. 

“In academia we tend to be isolated, and we’re focusing on one specific aspect of the problem,” Katsimpouras says. “With VIFF, we can reach out to multiple feedstock generators, community, stakeholders…. We didn’t know a lot about the dairy industry, and we keep learning. 

He adds, “Through VIFF we interact with other groups and explore solutions we may have in common.”