Applied Microbial and Cell Physiology

Applied Microbiology and Biotechnology

, Volume 89, Issue 5, pp 1611-1619

First online:

Growth and polyhydroxybutyrate production by Ralstonia eutropha in emulsified plant oil medium

  • Charles F. BuddeAffiliated withDepartment of Chemical Engineering, Massachusetts Institute of Technology
  • , Sebastian L. RiedelAffiliated withDepartment of Biology, Massachusetts Institute of Technology
  • , Florian HübnerAffiliated withDepartment of Biotechnology, Beuth Hochschule für Technik Berlin
  • , Stefan RischAffiliated withDepartment of Biotechnology, Beuth Hochschule für Technik Berlin
  • , Milan K. PopovićAffiliated withDepartment of Biotechnology, Beuth Hochschule für Technik Berlin
  • , ChoKyun RhaAffiliated withBiomaterials Science and Engineering Laboratory, Massachusetts Institute of Technology
  • , Anthony J. SinskeyAffiliated withDepartment of Biology, Massachusetts Institute of TechnologyDivision of Health Sciences and Technology, Massachusetts Institute of Technology Email author 

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Polyhydroxyalkanoates (PHAs) are natural polyesters synthesized by bacteria for carbon and energy storage that also have commercial potential as bioplastics. One promising class of carbon feedstocks for industrial PHA production is plant oils, due to the high carbon content of these compounds. The bacterium Ralstonia eutropha accumulates high levels of PHA and can effectively utilize plant oil. Growth experiments that include plant oil, however, are difficult to conduct in a quantitative and reproducible manner due to the heterogeneity of the two-phase medium. In order to overcome this obstacle, a new culture method was developed in which palm oil was emulsified in growth medium using the glycoprotein gum arabic as the emulsifying agent. Gum arabic did not influence R. eutropha growth and could not be used as a nutrient source by the bacteria. R. eutropha was grown in the emulsified oil medium and PHA production was measured over time. Additionally, an extraction method was developed to monitor oil consumption. The new method described in this study allows quantitative, reproducible R. eutropha experiments to be performed with plant oils. The method may also prove useful for studying growth of different bacteria on plant oils and other hydrophobic carbon sources.


Ralstonia eutropha Polyhydroxyalkanoate Polyhydroxybutyrate Plant oil Palm oil