In this study bioaugmentation using two monocultures was investigated, namely Methanosarcina barkeri and Methanococcus vanniellii. The volatile fatty acid concentration was lower compared to the non-bioaugmented reference which indicates faster nutrient degradation by bioaugmented experiments. The changes between the two cultures were minimal; however it was evident that Methanosarcina barkeri when applied to cheese whey produced biogas with increased rate compared to Methanococcus vanniellii. A 20% increase of biogas yield was obtained for both cultures. Both cultures, according to the measurements of biogas, volatile fatty acids and total organic carbon indicated good potential to be applied for bioaugmentation of cheese whey.