Aim: This study investigates the individual and combined effects of fermentation parameters for improving cell biomass productivity and the resistance to freezing, freeze-drying and freeze-dried storage of Lactobacillus delbrueckii subsp. bulgaricus CFL1. Methods and Results: Cells were cultivated at different temperatures (42°C and 37°C), pHs (5.8 and 4.8) and harvested at various growth phases (mid-exponential, deceleration and stationary growth phases). Specific acidifying activity was determined after fermentation, freezing, freeze-drying and freeze-dried storage. Multiple regression analyses were performed to identify the effects of fermentation parameters on the specific acidifying activity losses and to generate the corresponding 3D response surfaces. A multi-objective decision approach was applied to optimize biomass productivity and specific acidifying activity. The temperature positively influenced biomass