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Conversion of volatile fatty acids into polyhydroxyalkanoate by Ralstonia eutropha.
P Chakraborty1, W Gibbons, K Muthukumarappan
1Givaudan Flavors Corporation, Cincinnati, OH, USA. panchali.chakraborty@gmail.com
Journal of Applied Microbiology
|March 27, 2009
Summary
Condensed corn solubles (CCS) effectively support Ralstonia eutropha growth. Butyric and propionic acids are optimal for maximizing polyhydroxyalkanoate (PHA) production, reducing biopolymer costs.
Area of Science:
- Microbiology
- Biotechnology
- Biopolymer Production
Background:
- Ralstonia eutropha is a bacterium capable of producing polyhydroxyalkanoates (PHAs).
- Optimizing growth media and carbon sources is crucial for efficient PHA biosynthesis.
- Condensed corn solubles (CCS) are a byproduct of the ethanol industry with potential as a low-cost nutrient source.
Purpose of the Study:
- To optimize condensed corn solubles (CCS) as a fermentation medium for Ralstonia eutropha.
- To investigate the impact of individual volatile fatty acids (VFAs) on PHA production by R. eutropha.
- To identify optimal VFA concentrations for maximizing PHA yield.
Main Methods:
- Optimization of CCS medium concentration and C:N ratio for R. eutropha growth.
- Cultivation of R. eutropha in optimized CCS medium under controlled conditions (30°C, 120h).
- Individual feeding of various VFAs at different concentrations to assess their effect on PHA accumulation.
Main Results:
- An optimal CCS medium concentration of 240 g/L with a C:N ratio of 50:1 was determined.
- Comparable growth rates were observed between the optimized CCS medium and a defined medium.
- Butyric and propionic acids, when added at 5 g/L, significantly enhanced PHA production compared to other VFAs.
Conclusions:
- Optimized CCS medium effectively supports the growth of R. eutropha.
- Butyric and propionic acids are the most effective carbon sources for maximizing PHA production in this system.
- Utilizing CCS as a low-cost medium can reduce the commercialization costs of biopolymers.
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