Question

Microbiology

Q1

A phenol red glucose broth with a Durham tube has been inoculated and incubated. After 48 hours, the broth is turbid and bright yellow and approximately half of the contents of the Durham tube contains bubbles. Interpret these results. The organism will ferment lactose as well. The organism is fermenting glucose. The organism is an obligate anaerobe. The organism is fermenting lactose and producing ethanol and CO2.

Q2

Q3

Answer 1

Page 1 glucose Answer → The organism is terme. termeriting determine as glucose eose e The carbohydrate fermentation test is used to wheather not bacteria com ferment a lactose specifie carbohydrate such suerose. Phenol red is comm used as a immonly a pH indicator in Carbohydrate fermentation test and bus ham tubes are Inserted upside down in the test tube to deteet gas production. After incubation of 48 hours the broth is tuz bid and bright yellow, meant It indicates that because of the production of the acid, there is a drop of pH

Page 2 are indicate the production The bubble production Gas gas. that the organism So the is fermenting result suggent glucose. correet because ferment lactose other option are not It Then the organism will the broth pemein red phenol weed is colour of the lack absent of acid production. No bubble is seen in der Durham's tabe. due to The organisms is an obligate anaerobe: The term the term fermentation is often used to describe breaking down or eatabolism of a carbohydrate under anaroble conditions Therefore the bacteria Capable of fermenting carbohydrate sually tacul tative anaerobs. a are The organism and is fermenting lactose producing ethanol and co2 : Wen When Carbohydrates pH the organism ferments organic acid such as Cactie acid, formie acid orautie acid are obtain which turns the medium acidic (below pH 6.8 ) who and Colour Ethanol is not produced during Dus ham's tabe test. phenol red into yellow

Page 3 Answers - Motility, Hydrogen sulfide production. sim (sulfur, Indole, Motilility) media test the an organisms to do several things such reduce sulfeur, produce indole, swims through agar. Sulfur be reduced to H2S either by catabolism acid or by reduction of thiosulfate in anaerobie respiration. If hydrogen sultide is produced a black colour forms in the media. ability of Δις con of amino then the SIM tubes are incubated with a single stab to the bottom of the tube. If an organism is motile growth a will radiate from the Stab mark and make the entire tube turbid. Other options are not correct because Mannitol termentation O MSA media (Mannitol salt Agar) is both selective and differential media. The MSA media will select or genisms cowich can live in high salt concen- tration Organisms capable manitol as a tood using will produce acidic byproducts of fermentation low the pH of the media. of Source and Citrate utilization & to test an citrate agar is used to utilize citrate ΟΥ orgonism's ability as a source of energy.

Page 4 Kovae's reagent is added to test for indole. for determining the ability The indole test is a qualitative prod procedure of a bacteria to produce indole by deamination of tryptophan. Using kovaes tube combines presence tryptophan vich medium with P- Dimethylaminobenzalde hyde at an alid pH in alcohol and produce red violet compound method indole in the of a
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