Victor Ujor, an assistant professor in UW–Madison’s Department of Food Science, believes that whey shouldn’t go to waste. While cheese production creates one of Wisconsin’s most recognizable foods, it also generates whey permeate, a lactose-rich liquid byproduct that costs the dairy industry millions of dollars each year to manage. Ujor’s lab engineers genetically modified microorganisms that transform whey permeate and other agricultural byproducts into valuable chemicals used in biofuels, biodegradable plastics, pharmaceuticals, and other everyday products. These innovations could help Wisconsin’s dairy industry reduce waste, lower costs, and create value from one of the industry’s most abundant resources.
What is whey permeate, and why is it such a challenge for Wisconsin’s dairy industry?
In Wisconsin, we are richly endowed with cheese production. What most people don’t realize is that for every 10 parts of milk you convert to cheese, only one part goes to make cheese, and nine become whey. The industry filters the protein from whey because it’s valuable. But what is left behind is what we call whey permeate. It’s a liquid with a small amount of protein and a large amount of lactose, and you cannot just discard it. You have to treat it. An average-size plant in Wisconsin generates about 12.3 million gallons a year. That’s huge. It costs them money to treat it, whether they do it themselves or pay someone else to do it. It’s a major environmental and economic burden on both farmers and milk processors.
How can genetically modified bacteria turn waste into useful products?
Whey permeate contains lactose, and microorganisms love sugar. What we do in my lab is genetically modify bacteria that use the sugar. That allows us to tweak either the rate at which they use that lactose, or the rate at which they make the product we want, or both. We want them to take that lactose, use it fast enough, and make a high-value compound. We’ve made things like butanol. It’s used to make synthetic rubber, lacquer, and pharmaceuticals, but most of all, it’s an advanced biofuel. We’re also working on compounds used to make biodegradable plastics, food flavoring, fuel additives, deicers, and perfumes.
What excites you most about where this research could go next?
A wastewater treatment system can cost about $7 million to build, with ongoing operating costs of about $250,000 per year for an average-sized plant. So, it’s a huge economic burden on the industry. The final strategy would be to put a plant next to a huge cheese-making factory and say, “Okay, let’s go into a joint venture.” You either treat this waste, which costs you money, or we can pay you for every kilogram of our product we make, and we take all that waste off your hands. You pump it over; we sterilize it, put it into a huge vat, and add the microorganisms to make that product. What comes out of it is your product, water, and microorganisms. Microorganisms can be used to produce animal feed. The water no longer contains sugar, so you can treat it and put it back into the environment much more easily. And you have your product. In my opinion, for this to work, you have to partner with the dairy industry. It has to be strategically organized and work in tandem with the dairy industry for this to succeed.
What do people misunderstand about bacteria and genetic modification?
I think there’s a slice of society that thinks, when you talk about microorganisms, you are referring to death, germs, and disease. But we have fewer bad bacteria than good ones. Cheese comes from bacteria; yogurt comes from bacteria; beer, wine — you just name them. We’ve been using bacteria for hundreds of years to make these things. There’s also that general notion that genetically modified organisms are something to be concerned about. But it’s not exactly what people think.
I once asked someone at a presentation, “Do you know anybody who has Type 1 diabetes?” They said yes. I asked, “How do they stay alive?” They take insulin. Where do you think it comes from? We have genetically modified E. coli that makes it. Human growth hormone, antibodies, and many other things are made using genetically modified bacteria. These technologies already have huge benefits for people every day.
How could this research help create a more sustainable future?
It has a strong sustainability element. Back in the day, they used to take the whey and whey permeate and just dump it on the field. A little bit of it I can understand, but too much of it is bad. It contains lactic acid, it’s very acidic, and acidic soil doesn’t grow food. It also affects microorganisms in the soil and can kill biodiversity.
But most of all, you have all that sugar, lactose, which is what we call biochemical oxygen demand. When that gets into waterways, bacteria break it down and use up all the oxygen in the environment. The water becomes anoxic, biodiversity declines, and it’s just not good for the environment.
So, there’s a big sustainability element to this, and there’s a big economic piece as well. Our population is growing, and oil is not going to be sustainable in the long run, for both environmental and economic reasons. Using renewable methods economically will help us stay competitive in the future, but most importantly, [it will] make things in a way that’s safe for the environment while still making money.
