(82a) Bioconversion of Whey Lactose to Acetate and Propylene Glycol Deicers

Whey from cheese and yoghurt production operations contain significant amounts of lactose that is currently being unutilized and disposed of as waste. The treatment and disposal costs for these wastes are high due to the high biochemical oxygen demand (BOD) of these wastes. A novel low pH fermentation process will be discussed in this paper for the bioconversion of whey lactose to acetate and propylene glycol deicers as products. Acetate deicers are biodegradable and less harmful to the environment than the currently used non-biodegradable chloride deicers. A two-stage fermentation process using Lactobacillus plantarum in the first stage to convert lactose to lactate, and Lactobacillus buchneri in the second stage to convert lactate to acetate and propylene glycol was studied. Final product concentrations of 25 to 30 g/L of acetate and propylene glycol were obtained with lactose as the substrate. The fermentation pH was ~ 4.2, providing for efficient acid recovery. Kinetic data for separate sequential and coculture fermentation data will be presented.