Waste is, unfortunately, a mostly unavoidable part of life. When things are used up or leftover, we discard them and move on to the next fresh resource. Our world mostly abides by this linear system of take, make, use, and dispose.
Preserving resources, however, has never been more important, and we have an opportunity to move from a linear system to more of a circular economy, said John Lucey during the World Dairy Summit. The director of Center for Dairy Research at the University of Wisconsin-Madison explained that this approach means conserving the value of a product for a longer time through recycling and reusing.
Dairy farmers are no stranger to this concept. Their cows recycle by-products of human food processing every day. Manure nutrients are recycled onto farm fields. Dairies may recycle their water or even convert manure into biogas.
On the milk processing side, plants may also take steps to recycle their materials. Still, Lucey outlined that significant amounts of dairy co-products — things like whey permeate and acid whey — are also produced, and they often have no value except to be disposed of. He said that in a year, 120 billion pounds of liquid whey and 1 billion pounds of lactose are produced in Wisconsin alone. Often, this waste is shipped to off-site plants or land applied.
There are recycling opportunities, though. Research is being done and new items are being developed and on the market. Dairy co-products often contain a simple sugar and are consistent, making them good options for bacterial fermentation into innovative products, Lucey noted.
Plastics, wood, and more
One of those products is a biodegradable plastic that would not only use up dairy waste but change the way our world uses plastics. Ruihong Zhang, a professor in department of biological and agricultural engineering at the University of California, Davis, described how she is working to transform lactose whey permeate into a bioplastic.
Plastics are a serious environmental concern, especially in food manufacturing where they are mostly single use. Zhang sees bioplastics as a solution: they are biodegradable, so they can be composted, or they can be recycled. Polyhydroxyalkanoates (PHAs) are the fastest growing type of bioplastic, she explained, but their market share is still small because they are expensive to produce. “That’s where our dairy by-products come in,” Zhang stated.
Lactose whey permeate contains sugar and nutrients that makes it “great stuff to ferment,” she said. She’s been experimenting with a salt-loving, sugar-consuming bacteria called Haloferax mediterranei that can ferment whey into PHA at a 30% to 35% rate. “That’s a pretty good conversion,” described the scientist. In a bioreactor, the process takes about a week. Zhang and her team have developed a model for scaling the process up that she said would provide a fairly quick return on investment and low initial investment if the facility was put up near the cheese plants that produce whey.
Another novel option for whey permeate is to use it to stabilize wood. Julien Chamberland, a professor at the Université of Laval in Quebec, described that both dairy and timber are big industries in the province. He and a colleague treated black spruce and trembling aspen lumber with a mixture of whey permeate and citric acid, and they found that after a year outside, the treated products held up better to the weather because the mixture stabilized the cell walls of the wood. This could be a valuable use in construction, Chamberland said.
There are further efforts to use filtration to make dairy co-products more palatable and capture the nutrients inside. Sports drinks and more have been tested from these technologies. And encouragingly, whey specifically is a product of attention around many communities including research and athletics.
No easy solution exists to reducing waste. But if dairy farming continues its work to reuse resources and dairy processing innovations give co-products more value, the industry will have a very positive story to tell in how it is protecting our communities.