Two-stage continuous fermentation ofClostridium acetobutylicum:effects of pH and dilution rate

✍ Scribed by C. Godin; J. M. Engasser

• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 413 KB
• Volume: 33
• Category: Article
• ISSN: 1432-0614
• DOI: 10.1007/bf00164520

✦ Synopsis

The kinetics of a two-stage continuous fermentation of Clostridiurn acetobutylicum have been studied. The p H and the dilution rate have been shown to be two essential factors for process optimization. An increase in p H or dilution rate in the first stage decreased solvent production in the second fermentor. To achieve optimal solvent production, the p H had to be maintained at 4.5 in the first stage and between 4.5 and 5.0 in the second stage. Dilution rates of 0.08 h -1 and 0.04 h -1, respectively, in the first and second fermentots allowed a high solvent concentration. When the p H was maintained at 4.5 in each stage and when the dilution rates were 0.08 h -~ and 0.04 h -1 in the first and second fermentors respectively, 21 g/1 solvent concentration was achieved. A conversion yield of 0.36 g solvents/g glucose consumed was obtained with total consumption of glucose. Biomass was only produced in the first stage together with 40% of the solvents, indicating that solvent production had to be induced in the first fermentor.