ClassActivity5.docx

MCB3020L General Microbiology Laboratory

CLASS ACTIVITY WORKSHEET

Section: U01

Group: 5

Environment: Plant

Name: Thalia Ramos

ID: 6141550

Date: 03/08/2022

Title: Biochemical Testing- Selective vs. Differential Media.

Table 1:

Test	Picture	Result	Description
OF Medium		Tube with Oil (anaerobic): Reaction: positive Color: yellowish pH: acidic conditions	Metabolic reaction: Glucose wasn’t breaking down for the tube without oil, but it was broken down for the tube with oil meaning that the bacteria was able to fermentatively metabolize glucose. Enzymatic activity: Not applicable. Other: The unknown bacteria is anaerobic.
		Tube without Oil (aerobic): Reaction: negative Color: green pH: oxidative
Kligler’s Triple Iron Agar		Reaction: — positive/negative? Positive Color: red slant and yellowish butt. pH: acidic Other: No gas and no H2S present	Metabolic reaction: Glucose is only breaking down (fermented) Enzymatic activity: Other: The yellow color at the but is super light but it differentiates.
Litmus Milk		Reaction: — positive/negative? positive Color: blue pH: alkaline (basic) Other: Casein was breaking down into smaller components	Metabolic reaction: Protein casein was metabolized Enzymatic activity: Lactose wasn’t fermented. Other: Unknown bacterial utilized milk components to metabolize.
Nitrate Reduction		Reaction: — positive/negative? Positive Color didn’t change Color: no color change pH: basic Other: color looks light/clear yellowish	Metabolic reaction: Nitrates have been broken down. Enzymatic activity: Nitrates are not in the solution Other: Bacteria didn’t break down nitrates into nitrites. Zinc was added.
Gelatin Hydrolysis		Reaction: — positive/negative? Negative Color: light/clear yellow pH: acidic Other: Stay solid even after ice bath.	Metabolic reaction: No liquefaction occurred meaning that gelatin wasn’t removed. Enzymatic activity: Gelatinase didn’t break down gelatin. Other: Gelatin wasn’t removed
Urease		Reaction: — positive/negative? Positive Color: pink agar- clear bacteria pH: alkaline (basic) Other: Can’t even differentiate between the colonies and the agar.	Metabolic reaction: Urea was broken down by urease Enzymatic activity: Urea was broken down by urease enzyme Other: Ammonia formation
Starch Hydrolysis		Reaction: — positive/negative? Positive Color: purple in agar and yellowish in the bacteria colonies. pH: acidic Other: after a while colony turned whiter.	Metabolic reaction: Iodine turned purple in the presence of starch. Enzymatic activity: alpha amylase hasn’t break down starch because still present in the agar plate.
Methyl Red (48 hours)		Reaction: — positive/negative? negative Color: yellow pH: basic	Metabolic reaction: No fermentation was used Enzymatic activity: No dextrose/glucose was broken down into pyruvate Other: Used to test metabolic pathway (fermentation specifically)
Voges-Proskauer (48 hours)		Reaction: — positive/negative? Negative Color: no color change pH: basic	Metabolic reaction: Glucose was not fermented using the 2,3 butanediol pathway. Enzymatic activity: Acetoin is not preset. Other: no glucose fermented
Catalase		Reaction: positive/negative? Positive Color: white pH: alkaline (basic) Other: catalase present	Metabolic reaction: Reaction is positive because hydrogen peroxidase was broken down into water and oxygen. Enzymatic activity: catalase was present Other: Bacteria utilizes catalase enzyme.
Oxidase		Reaction: — positive/negative? Negative Color: no color change pH: acidic	Metabolic reaction: Bacteria didn’t produce or utilized Cytochrome-C Enzymatic activity: No Cytochrome-C present because bacteria didn’t change color.

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