Enhanced Butyric Acid Production by Clostridium tyrobutyricum Adapted on Xylose and 2-deoxy-D-glucose Mixture

Title
Enhanced Butyric Acid Production by Clostridium tyrobutyricum Adapted on Xylose and 2-deoxy-D-glucose Mixture
Authors
김기연이경민차창준상병인엄영순
Keywords
Clostridium tyrobutyricum; adaptation; glucose; xylose; co-fermentation; 2-deoxy-d-glucose
Issue Date
2012-09
Publisher
International Biotechnology Symposium and Exhibition
Abstract
Clostridium tyrobutyricum ATCC 25755 is one of the most representative bioproducers for butyric acid. This strain was capable of utilizing glucose and xylose simultaneously. However, the xylose utilization rate was much lower than the glucose utilization rate. Furthermore, there was a diauxie after complete depletion of glucose. Consequently, the final butyric acid productivity was lower in the mixture than in glucose. In this study, we developed an adaptive cultivation system to improve the xylose utilization rate and to release diauxic lag. When the strain was adapted on xylose with the varying concentrations of 2DG, the higher level of 2DG-adadpted strain showed the faster xylose utilization rate but the slower glucose utilization rate, which is undesired property. Eventually, we developed optimally adapted strain (OPS) exhibiting similar glucose and xylose consumption rate. The OPS did not show a diauxie in the mixed sugars. Interestingly, when the OPS was cultivated in the medium containing only glucose as a carbon source, the glucose consumption rate was fully regenerated up to that of the wild while keeping high xylose utilization rate of OPS. Finally, the regenerated strain of OPS showed the most efficient butyric acid production with the highest xylose and glucose utilization rate. Acquired phenotypes were maintained when the cells were cultivated in the medium containing xylose as sole carbon source without 2DG. In conclusion, we successfully developed an adaptive and regenerative cultivation system to improve the productivity of butyric acid by C. tyrobutyricum from glucose and xylose mixture by improving xylose consumption rate and releasing diauxie.
URI
http://pubs.kist.re.kr/handle/201004/43116
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KIST Publication > Conference Paper
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