Kingdom Bacteria Order Enterobacteriales Genus Raoultella Higher classification Raoultella | Phylum Proteobacteria Family Enterobacteriaceae Scientific name Raoultella planticola Rank Species | |
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Similar Raoultella, Bacteria, Enterobacteriaceae, Klebsiella oxytoca, Hafnia | ||
Raoultella planticola is a Gram-negative bacterium of the genus Raoultella. R. planticola is quite similar in appearance to Klebsiella pneumoniae and must be identified based on growth habits or DNA analysis. A number of strains have been identified. R. planticola has been determined to have complicated at least one case of severe pancreatitis.
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Strains
A strain of Raoultella planticola, Cd-1 has been found which grows anaerobically at high aqueous cadmium concentrations and precipitates insoluble cadmium sulfide. This strain has been isolated from reducing salt marsh sediments and may be useful in bioremediation of cadmium from exposed soils.
Taxonomic reclassification
Raoultella planticola was formerly classified as part of the genus Klebsiella. It was reclassified along with several other Klebsiella species in 2001.
Genetic modification
In the late 1980's R. planticola was genetically modified by inserting a plasmid from Zymomonas mobilis. This plasmid codes for the enzyme pyruvate decarboxylase which, along with alcohol dehydrogenase already present in the bacteria allow it to produce ethanol. The bacteria already does produce ethanol when metabolizing hexoses and pentoses, but very inefficently. R. planticola was chosen to receive this gene as it already had metabolic pathways to breakdown pentose sugars such as xylose, which is a main component of agricultural and forest residues. The results showed that the genetically modified strain could produce ethanol but were killed at concentrations of ethanol greater than 5%. The modified strain also produced more ethanol at lower pH (5.4) and ethanol production decreased as pH increased.
In the early 1990s a biotech company set out to solve a problem: how to destroy crop residue safely. Some crops' residues harbor plant pathogens. Burning is occasionally used to destroy the residue and pathogens, but this is a fire hazard and can be dangerous for the environment. This company realized that, because R. planticola is an aggressive and abundant soil bacterium, it could be genetically modified to destroy crop residue and also create ethanol.
Testing of this process, however, was limited to sterile soil. Ph. D. research conducted at Oregon State University, supervised by Elaine Ingham, obtained a sample of the genetically modified organism for assessing ecological effects through the German Institut für Biotechnologie and, testing it in non-sterile (ordinary) soil, found that the modified bacteria caused mass plant death from the ethanol production. R. planticola is ubiquitous, found growing in the root systems of all kinds of plants everywhere. Therefore, some have speculated that without the independent test, the genetically modified bacteria might have been introduced in nature and then could have spread to contaminate the biosphere where it would cause worldwide plant death.
Fallacy of GMO claims
Public testimony of Ingham and others claims of "worldwide plant death" attracted attention from the scientific community. They were unable to find any evidence that Dr Ingham had submitted her assertions about threats to terrestrial plant life to scientific publication in a peer-reviewed journal, and no evidence was found to indicate the U.S. EPA or U.S. Dept. of Agriculture had reviewed or approved any trails for SDF20. Additionally, the SDF20 was found to have produce 20 micrograms per milliliter of alcohol in the soil which is several hundred times lower than that required to affect plant growth.
Elaine Ingham has issued a public apology for submitting false claims about ecological impact of GMOs.
The Green Party has issued a public apology for misleading statements and acknowledging that a cited research was never published.