For the practical feasibility of lactic acid (LA) fermentation process, a continuous operation using mixed culture and the use of cheap and non-food raw materials are essential. In this study, a continuous LA fermentation of food waste was attempted using indigenous mixed culture. During the operation, temperature was gradually increased from 35℃ to 55℃, with showing the highest performance at 50℃. At 35-45℃, other organic acids such as acetic acid and butyric acid were also observed. At 50℃ and HRT 1.0 d, both LA production yield and its productivity were maximized to 1.8 mol LA/mol hexoseadded and 1.4 g LA/L/hr, respectively. A pyrosequencing result showed that Lactobacillus amylolyticus was the predominant species performing LA fermentation of food waste. The combined process of nanofiltration and water-splitting electrodialysis could recover highly purified LA from the fermentation broth by removing 95% of mineral ions and 77% of ammonium and glucose.

• Dong-Hoon Kim(Clean Fuel Department, Korea Institute of Energy Research)
• Jeong-Geol Na(Clean Fuel Department, Korea Institute of Energy Research)
• Mo-Kwon Lee(Clean Fuel Department, Korea Institute of Energy Research)
• Mi-Sun Kim(Clean Fuel Department, Korea Institute of Energy Research)
• Jae-Hyung Kim(Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology)
• Yong-Keun Chang(Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology)
• Wan-Taek Lim(KAIST Institute for Biocenter, Korea Advanced Institute of Science and Technology)