MICROBIOLOGY GTC LAB FINAL
1. Catalase Test 1. Obtain a clean glass slide
2. Using loop, aseptically smear small amount on to one side of the slide then the
other
3. Add one or two drops of hydrogen peroxide to each bacteria.
4. Observe results. Bacteria that make catalase will cause solution to bubble.
2. Catalase Test pur- Ditterential Test
pose To determine which bacteria has the catalase to breakdown hydrogen peroxide
into oxygen and water; also used to ditterentiate gram positive, however many
Gram negatives use catalase as well
3. Amylase Test 1. Obtain agar culture of bacteria
2. Obtain starch hydrolysis plate and on bottom of plate divide into two sections
3. Label bacteria names on each side
4. Using an inoculation loop, zig zag a line of bacteria on each side.
5. Incubate at the plates upside down at 37 C remove in 24-24 hours.
On next lab
1. Place 1 ml of Lugol's Iodine solution onto the agar plate. Iodine will cause starch
to turn deep brown-black color if it is still present.
2. Look for a clearing in the agar around the bacteria. Make sure you do not tip the
agar plate as the iodine will leak out. When bacteria produces amylase, the starch in
the agar will be broken down. Will observe a clearing around the colonies (amylase
positive-clear agar under bacteria) no visibility through iodine test negative.
4. Amylase Test pur- Ditterential Test
pose Used to ditterentiate gram positive. Amylase extracellular enzyme, breaks down
starch to use sugar to go in cell to be use as energy. Used to ditterentiate gram
positive
, MICROBIOLOGY GTC LAB FINAL
5. Urease Test 1. Obtain agar cultures of bacteria.
2. Obtain 2 urease agar tubes and label them.
3. Using needle inoculate the urease tubes with the stab and streak technique.
4. Incubate 37 C will be removed after 24-48 hours
Test positive entire tube is pink and yellow if negative
6. Urease Test pur- Ditterential Test
pose Used to ditterentiate gram negatives. Urease is also extracellular enzyme that
breaks down urea to ammonia and carbon dioxide.
Trying to determine which bacteria has the ability to urease enzyme that catalyze
the conversion of urea to ammonium and carbon dioxide, thus
which bacteria can exist in a acidic environment.
7. Triple Sugar Iron 1. Obtain agar slant cultures of bacteria
(TSI) Agar 2. Obtain three tubes of TSI agar
3. Use stab and streak technique to inoculate the TSI agar slant with an inoculating
needle, aseptically transfer bacteria from culture tube to the TSI tube, then stand
and (push the needle to the bottom of the tube) an streak (zigzag over the surface
of the agar).
4. Incubate the tubes at 37 C, Tubes will be removed in 24-28 hours.
+ sugar turns from red (contain phenol red a ph indicator, turns yellow in presence
of acid) in to yellow
-H2S production if black to iron isnt seen.
8. Triple Sugar Iron Ditterential Test
(TSI) purpose Used to ditterentiate Gram negative. Determine the ability of a bacteria to ferment
1. Catalase Test 1. Obtain a clean glass slide
2. Using loop, aseptically smear small amount on to one side of the slide then the
other
3. Add one or two drops of hydrogen peroxide to each bacteria.
4. Observe results. Bacteria that make catalase will cause solution to bubble.
2. Catalase Test pur- Ditterential Test
pose To determine which bacteria has the catalase to breakdown hydrogen peroxide
into oxygen and water; also used to ditterentiate gram positive, however many
Gram negatives use catalase as well
3. Amylase Test 1. Obtain agar culture of bacteria
2. Obtain starch hydrolysis plate and on bottom of plate divide into two sections
3. Label bacteria names on each side
4. Using an inoculation loop, zig zag a line of bacteria on each side.
5. Incubate at the plates upside down at 37 C remove in 24-24 hours.
On next lab
1. Place 1 ml of Lugol's Iodine solution onto the agar plate. Iodine will cause starch
to turn deep brown-black color if it is still present.
2. Look for a clearing in the agar around the bacteria. Make sure you do not tip the
agar plate as the iodine will leak out. When bacteria produces amylase, the starch in
the agar will be broken down. Will observe a clearing around the colonies (amylase
positive-clear agar under bacteria) no visibility through iodine test negative.
4. Amylase Test pur- Ditterential Test
pose Used to ditterentiate gram positive. Amylase extracellular enzyme, breaks down
starch to use sugar to go in cell to be use as energy. Used to ditterentiate gram
positive
, MICROBIOLOGY GTC LAB FINAL
5. Urease Test 1. Obtain agar cultures of bacteria.
2. Obtain 2 urease agar tubes and label them.
3. Using needle inoculate the urease tubes with the stab and streak technique.
4. Incubate 37 C will be removed after 24-48 hours
Test positive entire tube is pink and yellow if negative
6. Urease Test pur- Ditterential Test
pose Used to ditterentiate gram negatives. Urease is also extracellular enzyme that
breaks down urea to ammonia and carbon dioxide.
Trying to determine which bacteria has the ability to urease enzyme that catalyze
the conversion of urea to ammonium and carbon dioxide, thus
which bacteria can exist in a acidic environment.
7. Triple Sugar Iron 1. Obtain agar slant cultures of bacteria
(TSI) Agar 2. Obtain three tubes of TSI agar
3. Use stab and streak technique to inoculate the TSI agar slant with an inoculating
needle, aseptically transfer bacteria from culture tube to the TSI tube, then stand
and (push the needle to the bottom of the tube) an streak (zigzag over the surface
of the agar).
4. Incubate the tubes at 37 C, Tubes will be removed in 24-28 hours.
+ sugar turns from red (contain phenol red a ph indicator, turns yellow in presence
of acid) in to yellow
-H2S production if black to iron isnt seen.
8. Triple Sugar Iron Ditterential Test
(TSI) purpose Used to ditterentiate Gram negative. Determine the ability of a bacteria to ferment
