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Growth enhancement of bioethanol-producing microbe Clostridium autoethanogenum by changing culture medium composition

Park, Soeun, Ahn, Bohye, Kim, Young-Kee
Bioresource technology reports 2019 v.6 pp. 237-240
Clostridium autoethanogenum, acetic acid, acetogens, cell growth, culture media, ethanol, sodium sulfide, synthesis gas, trace elements, yeast extract
The aim of this study was to optimize the culture medium to enhance the growth of Clostridium autoethanogenum, an acetogenic bacterium that converts synthesis gas to ethanol and acetic acid. In order to optimize the culture medium, four components, yeast extract, trace metal solution, vitamin solution, and Na2S·9H2O, were investigated. Yeast extract was found to have the biggest influence on growth, and a concentration of 5 g/L, 10 times higher than that in basal medium, leading to 2.3 times greater growth. At 10 times the concentration in basal medium, trace metal solution inhibited the growth of the acetogen. A change in the concentration of vitamin solution did not yield any significant difference in cell growth. Lastly, growth with Na2S·9H2O showed a tendency to decrease after an initial cell mass increase for concentrations of 0.5 g/L (basal medium condition) and 0.05 g/L. However, at 5 g/L, C. autoethanogenum grew steadily.