Acid whey treatment and conversion to single cell protein via aerobic yeast activated sludge

In this study, a synthetic acid whey was made to mimic acid whey produced during cheese manufacture. A mixed yeast culture, primarily Vanrija albida, was used to degrade the wastewater and produce a single cell protein (SCP). The system was operated in batch mode at high and low loading rates. The COD-use efficiency of the biomass was 93 and 85% at the high and low loading rates, respectively. The pH was maintained at 3.5 to prevent bacterial contamination of the system. High loading and high oxygen transfer efficiency indicate that a full-scale yeast system would probably offer significant cost savings over both aerobic and anaerobic bacterial systems. The biomass produced has the potential to be a valuable commodity. The biomass amino acid profile was good with respect to the FAO protein nutrition guidelines for various farmed livestock species.