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Oxidative/fermentation glucose test (OF glucose test) is a biological technique. It was developed in 1953 by Hugh and Leifson to be utilized in microbiology to determine the way a microorganism metabolizes a carbohydrate such as glucose (dextrose). [ 1 ]
The TSI slant is a test tube that contains agar, a pH-sensitive dye , 1% lactose, 1% sucrose, 0.1% glucose, [2] and sodium thiosulfate and ferrous sulfate or ferrous ammonium sulfate. All of these ingredients are mixed together, heated to sterility, and allowed to solidify in the test tube at a slanted angle.
Cystine tryptic agar (CTA), also known as cystine trypticase agar, [1] [2] is a growth medium used for the identification of microorganisms. [3]It can be used to determine if organisms can ferment various carbohydrates, including maltose, lactose, and sucrose.
It is used to determine the ability of some organisms to produce a neutral end product, acetyl methyl carbinol from glucose fermentation.The production of acetoin, a neutral reacting end product produced by members such as Klebsiella, Enterobacter etc., is the chief end product of glucose metabolism and form less quantities of mixed acids.
Its hydrogen yield is lower than that of such strict anaerobes as Clostridia: strictly anaerobic bacteria produce a theoretical maximum of 4 mol H 2 /mol glucose, while such facultative anaerobic bacteria as K. aerogenes theoretically yield a maximum of 2 mol H 2 /mol glucose. [6] K. aerogenes may spoil maple sap and syrup. [7]
Sugar fermentation lowers the pH and the phenol red indicator registers this by changing to yellow. Most gut bacteria, including Salmonella, can ferment the sugar xylose to produce acid; Shigella colonies cannot do this and therefore remain red.
Glucose fermentation in this species can be demonstrated through the triple sugar iron test. Specific tests include positive urease (which is the fundamental test to differentiate Proteus from Salmonella ) and phenylalanine deaminase tests.
Lactic acid fermentation is a metabolic process by which glucose or other six-carbon sugars (also, disaccharides of six-carbon sugars, e.g. sucrose or lactose) are converted into cellular energy and the metabolite lactate, which is lactic acid in solution.