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The citrate test detects the ability of an organism to use citrate as the sole source of carbon and energy. == Principle == Bacteria are inoculated on a medium containing sodium citrate and a pH indicator such as bromothymol blue. The medium also contains inorganic ammonium salts, which are utilized as sole source of nitrogen. Use of citrate involves the enzyme citritase, which breaks down citrate to oxaloacetate and acetate. Oxaloacetate is further broken down to pyruvate and carbon dioxide (CO2). Production of sodium bicarbonate (NaHCO3) as well as ammonia (NH3) from the use of sodium citrate and ammonium salts results in alkaline pH. This results in a change of the medium’s color from green to blue. Bacterial colonies are picked up from a straight wire and inoculated into slope of Simmons citrate agar and incubated overnight at 37 °C. If the organism has the ability to use citrate, the medium changes its color from green to blue. Examples: * ''Escherichia coli'': Negative * ''Klebsiella pneumoniae'': Positive * ''Frateuria aurantia'': Positive 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Citrate test」の詳細全文を読む スポンサード リンク
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