Fermentation produces
acids
alcohols
gas
True or false. Nutrient agar there is no differentiation.
True
Carbohydrate fermentation procedure
Obtain 4 of each carbohydrate fermentation tubes:
glucose
sucrose
lactose
Obtain one each of the following: E. coli, E. aerogenes, A. faecalis, P. vulgaris
inoculate each set with each bacteria
Why is the durham tube upside down?
to detect gas production
carbohydrate fermentation media:
broths
uninoculated color: red
contains:
one peptone
durham tube
phenol red (pH indicator)
Phenol red is a pH indicator
yellow- positive for sugar fermentation pH lower
red- no change pH stayed same
pink/magenta- it couldn't metabolize the sugar and use for food so it metabolized the protein pH higher
The carbo. tube is full and no bubbles
positive for acid fermentation
Carbo tube has bubbles in durham tube
positive for gas fermentation
carbo tube has no change in color or gas production
negative for fermentation
Carbo tube is orange
Intermediate zone- (-) for fermentation
True or false. Bacteria can ferment a variety of carbohydrates through different pathways. No single bacterial species is capable of them all.
true
_______ it typically the starting point of carbohydrate fermentation.
pyruvic acid
True or false. Acids and/or gases may be produced as products of fermentation.
true
Fermentation ability depends on ______ and the ______ it produces.
bacteria
enzymes
Carbohydrate fermentation theory
positive for acid production
pH decreases
phenol red becomes yellow and turns media yellow
If positive for gas production in carbohydrate fermentation
media in durham tube is displaced
bubble forms within durham tube
Carbohydrate fermentation results:
yellow broth bubble in durham tube
positive for fermentation with gas and acid products
Carbohydrate fermentation results:
yellow broth no bubble in tube
positive for fermentation with acid products
Carbohydrate fermentation results:
red broth no bubble in tubes
no fermentation- no acid or gas production
Carbohydrate fermentation results:
pink broth no bubble in tube
protein catabolism: alkaline end product
no acid or gas
Carbohydrate fermentation results:
orange broth
negative for fermentation no gas or acid
MRVP results
red is positive for both tests
MRVP is _____ test and they are _____ and ______.
2
methol red
vogues proskauer
The methol red test is testing for?
mixed stable acids fermentation
it overcomes the buffer and changes the pH
The VP test is for?
to check for the production of acetoin
Methyl red test you add __ drops to the MRVP broth
5
In the methyl red test if the broth remains red than it is _____________.
positive for the production of mixed stable acids
The MRVP test contains:
glucose
protein
phosphate buffer (resists pH change)
In the methyl red test it is used to detect large amounts of ________.
mixed stable acids
acids are stable and overcome buffer
cause pH change
True or false. In the methyl red test the only true indication of a positive fermentation for mixed stable acids is ______.
red color
The VP test you add
12 drops of reagent 1 which is _________.
And 2-3 drops of reagent 2 which is __________.
a-napthol
KOH
In VP test after adding reagents put paraffin cover and shake vigorously and let stand for 30 mins
Results:
Light brown tea color (-) for acetoin production
Red or red band at top is positive for acetoin production
In the VP test it is the fermentation of ______ that produces acetoin.
glucose
Citrate test is done in a _______ and you ______ to inoculate the tube.
slant-green (solid) and you zig zag up to inoculate it
Citrate media is:
slant-solid media/green
One carbon source- sodium citrate (carbon)
One nutrient source monoammonium (nutrient)
Bromthymol blue- pH indicator
dipotassium phosphate
magnesium sulfate (cofactor for enzymes)
agar
The positive result of citrate is
green-----> blue
For the citrate test the bacteria need both ____ and ______.
carbon and energy
The citrate test tests the bacteria's ability to
obtain both carbon and energy
The citrate test allows differentiation between different members of Enterobacteriacea
enteric bacteria
If the citrate test is positive bacteria
produce citrate lyase
make ammonia from ammonium
increase the pH of agar
media turns a deep Prussian blue
Citrate test results:
blue even a small amount
positive
citrate is utilized
Citrate test results:
No color change; growth
citrate is utilized; positive
Citrate test results:
no color no growth
citrate not utilized
negative citrate test
KOH is
potassium hydroxide
a-napthol is used with KOH to detect
acetoin