UPGRADING DAIRY INDUSTRY WASTE THROUGH MICROBIAL ENGINEERING

The dairy industry in the United States has experienced unprecedented consumer demand for Greek yogurt resulting in a dramatic increase in its production. Over the past decade, Greek yogurt's market share in the US has skyrocketed from less than 2% to approximately 45%. However, the Greek yogurt's production process leaves behind a high-volume, liquid waste stream called acid whey (AW). It is estimated that more than 3 million tons of AW are generated each year in the US alone. Overall, no good solution exists while a large volume of potential fermentable nutrients such as lactose, galactose, and lactic acid remains unutilized. Moreover, this yellowish by-product is unappealing to the food industry as its acidic and salty taste, high levels of ash, and low levels of protein limit its food applications. Therefore, AW, besides being an environmental problem, is also a costly nuisance to the dairy industry. This project addresses this issue by developing an environmentally friendly and efficient process that can be easily fitted into existing Greek yogurt producing facilities and achieves two goals: [1] bioremediates this dairy industry waste minimizing its treatment costs and environmental burden, and [2] generates a revenue stream from the production of higher value-added products. To achieve this goal, we propose the bioconversion of AW to valuable food and feed ingredients and/or microbial animal feed by engineering Yarrowia lipolytica.