Scale-up of anaerobic 1,3-propanediol production by Clostridium butyricum DSP1 from crude glycerol

摘要

Background As the production of biofuels from raw materials continuously increases, optimization of production processes is necessary. A very important issue is the development of wasteless methods of biodiesel production. One way of utilization of glycerol generated in biodiesel production is its microbial conversion to 1,3-PD (1,3-propanediol). Results The study investigated the scale-up of 1,3-PD synthesis from crude glycerol by Clostridium butyricum. Batch fermentations were carried out in 6.6?L, 42?L and 150?L bioreactors. It was observed that cultivation of C. butyricum on a pilot scale did not decrease the efficiency of 1,3-PD production. The highest concentrations of 1,3-PD, 37?g/L for batch fermentation and 71?g/L for fed-batch fermentation, were obtained in the 6.6?L bioreactor. The kinetic parameters of 1,3-PD synthesis from crude glycerol established for batch fermentation were similar regarding all three bioreactor capacities. During fed-batch fermentation, the concentration of 1,3-PD in the 150?L bioreactor was lower and the substrate was not completely utilized. That suggested the presence of multifunctional environmental stresses in the 150?L bioreactor, which was confirmed by protein analysis. Conclusion The values of effectivity parameters for 1,3-PD synthesis in batch fermentations carried out in 6.6?L, 42?L and 150?L bioreactors were similar. The parameters obtained during fed-batch fermentations in the 150?L bioreactor differed in the rate and percentage of substrate utilization. The analysis of cell proteins demonstrated that a number of multifunctional stresses occurred during fed-batch fermentations in the 150?L bioreactor, which suggests the possibility of identifying the key stages in the biochemical process where inhibition of 1,3-PD synthesis pathways can be observed.