Production of Value-Added Bioproducts Using a Modified Continuous Biofilm Reactor by Citrobacter Freundii DSM 15979

Abstract

The present paper reports the results of Citrobacter freundii, strain DSM 15979, that was tested for its ability to produce value added chemicals from biodiesel derived glycerol in a mesophilic fluidized bed biofilm reactor operating under continuous conditions at a specified hydraulic retention time (HRT) at 30°C. Elevating feed concentrations (10 to 144 g/L) were tested in order to understand their effects on simultaneous production of value added products with immobilized whole cells. Gin was found to be a significant independent variable for the productions of 1,3-PDO, 2,3-BD, ethanol, acetic, succinic and lactic acids under different organic loading rates (OLR). The major metabolite in the metabolic pathway was found to be 1,3-PDO followed by 2,3-BD reaching the maximum values as 26.1 and 18.8 g/L under the conditions of 92 g/L crude glycerol and 8 h, which is represents an OLR of 11.5 g/L.h, suggesting the formation of biofilms favor the utilization of high substrate concentration to enhance the mixed fermentation.

Keywords

• glycerol fermentation
• biofilm
• citrobacter freundii