RESEARCH SPOTLIGHT: Fermenting surplus skim milk into a value-added product
This week, we are highlighting the work of master’s student Lucas Wise. Lucas is focusing on repurposing surplus skim milk into a value-added product. High prevalence of lactose intolerance in the world and increased demand for plant-based milk alternatives has caused a decline in skim milk consumption. For producers, this is resulting in financial loss and environmental damage from increasing skim milk waste. The goal of his project is to develop technologies to derive added value compounds, ingredients, and products from skim milk via the fermentation of lactose.
While traditional brewer’s yeast, Saccharomyces cerevisiae, can’t ferment lactose, alternative yeasts can externally break down lactose into its two smaller subunits, glucose and galactose. Non-Saccharomyces yeasts can also selectively ferment the glucose, leaving galactose behind to be recovered!
Galactose is a low glycemic index sugar, meaning that it doesn’t cause a huge spike in blood sugar levels after its ingestion. Galactose can be used to make healthier snacks and beverages, serve as a pre-cursor to other “rare” sweeteners like tagatose, and can be used in pharmaceuticals and health-promoting galactooligosaccharrides, which are prebiotics.
The anaerobic fermentation of lactose also produces ethanol, the ingredient in all of our favorite drinks!
The fermentation process can leverage the lactose in discarded skim milk and provide an alternative method of upcycling this dairy waste, easing the burden of waste on dairy producers. Companies could avoid major financial losses and reduce their environmental impact because the skim milk surplus gets repurposed.
Currently, Lucas is in the screening stage, using a variety of yeast species to determine the best process performance parameters and improve the fermentation stability and sensory properties of the product. This will be followed by an optimization seeking to maximize ethanol and galactose yields from the fermentation. This work could potentially be used to create a stand-alone fermented beverage!