Utilization of Dairy Sludge as an Alternative Medium for Biomass and Exopolysaccharide Production by Enterococcus durans k۴۸ Isolated from Iranian Traditional Kishk

Dairy sludge, a by-product of milk processing, was evaluated as an alternative low-cost medium for biomass and exopolysaccharide (EPS) production by Enterococcus durans K۴۸ isolated from Iranian traditional kishk. The sludge contained %۲۹.۳۲ _x۰۰۰۰__x۰۰۰۰_ ۰.۴۲ protein and %۳۰.۱۷ _x۰۰۰۰__x۰۰۰۰_ ۰.۹۳ total carbohydrate before spray-drying, decreasing to %۲۸.۲۹ _x۰۰۰۰__x۰۰۰۰_ ۰.۵۰ after spray-drying. Optimization by Design-Expert using RSM (CCD) indicated maximum biomass yield at ۱۵% sludge, ۵% sucrose, and ۲.۵% yeast extract. Under these conditions, E. durans K۴۸ produced ۳۹۰ mg/L EPS, confirming the suitability of dairy sludge as a sustainable fermentation substrate.