title: Scale-up of anaerobic 1,3-propanediol production by Clostridium butyricum DSP1 from crude glycerol.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Biotechnology and Food Microbiology, Poznań University of Life Sciences, Wojska Polskiego 48, Poznan, 60-527, Poland. darszy@up.poznan.pl.
authors.forename: Daria
authors.initials: D
authors.lastname: Szymanowska-Powałowska
authors.forename: Wojciech
authors.initials: W
authors.lastname: Białas
mesh_terms: D001709:Biotechnology / Q000379:methods; D001711:Biotransformation; D046972:Clostridium butyricum / Q000378:metabolism*; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D011409:Propylene Glycols / Q000378:metabolism*
chemical_list: D011409:Propylene Glycols; C041787:1,3-propanediol; D005990:Glycerol