By optimization of the fermentation conditions lactic acid yield of 18.6 g/L and high biomass production were realized on the stillage from the production of bioethanol on waste breadby Lb. rhamnosus ATCC 7469 [62]. Inthisstudy possibilities of parallel production of lactic acid and probiotic biomass were assessed. Although a precise economical analysis has not been performed yet, a positive economical effect of thin stillage utilization is already obvious, as well as a positive environmental effect.