Whey is a coproduct of the cheese or casein manufacture used as an animal feed supplement. Despite its high energy density, its usage is limited in high production cows due to the low protein content in proportion to the salt and lactose content.
The lactose fraction in whey constitutes approximately 65% of the total dry solids while the protein fraction represents about 10% of the product. To overcome this issue, Pennsylvania researchers proposed a method in 1958 for ammonia buffering of whey while undergoing lactic acid fermentation. The method involved the fermentation of cheese whey with Lactobacillus bulgaricus, followed by subsequent treatment of the whey with anhydrous ammonia to neutralize the lactic acid formed during fermentation. Fermented ammoniated condensed whey (FACW) is rich in lactate, a gluconeogenic precursor.