2-acetic acid bacteria Flashcards
____ and ____ must be present in an acetic fermentation
alcohol and oxygen
Amylolytic fermentation uses ____
molds
____ is a mold that is used in amylolytic fermentations
Aspergillus oryzae
Rhizopus oryzae is used for ___ fermentations
prteolytic
Penicillium on the outside of cheeses is an exemple of ___ fermentations
proteolytic
What is the formula of acetic acid
CH3COOH
What is the other name of acetic acid
ethanolic acid
AAB are gram ___
negative
Does all bacteria that produces acetic acid are considered AAB
no because if the bacteria produce acetic acid via the anaerobic fermentation it is not considered acetic acid bacteria (acetogenic bacteria).
most vinegar is produced by ____ (bacteria name)
acetobacter sp.
What is an acetogenic bacteria?
a bacteria that produces acetica acid anaerobically
___ and ____ are only able to use ethanol
Acetobacter and Komagataeibacter
_____ can use several sugars or sugar alcohols such as D-glucose, D-sorbitol, and glycerol in addition to ethanol
Gluconobacter
____ do not have a functional TCA cycle since they are missing key enzymes, therefore they are unable to metabolize organic acids
Gluconobacter
What are the two types of acetic acid fermentation
- Surface static processes 2. submerged processes
What are the four mechanisms responsible for the AAB resistance to acetic acid
- Prevention of acetic acid influx into the cell (CPS, EPS, and LPS) 2. Acetic acid assimilation (overoxidation) 3. Acetic acid efflux (efflux pumps) 4. Protection of cytoplasmic proteins against denaturing (general stress proteins)
____ is a chaperone that is representative of heat-shock proteins that are found in all bacteria
GroES-GroEL
____ This chaperone has various functions including folding nascent proteins, refolding denatured proteins, and degrading seriously denatured proteins
DnaK-DnaJ-GrpE
What is spontaneous fermentation?
Which is based on the action of wild microorganisms that are already naturally on the food or in the area. You encourage the growth of certain microbes by creating optimal conditions for them (sauerkraut).
What is inoculated fermentation ?
Which is based on introducing a single pure culture or several (mixed culture) into an environment that is favorable to their proliferation. The advantage is that it stabilizes fermentations which are sensitive to contamination (wine).
What is the advantage of the inoculated fermentation ?
it stabilize the fermentations which are sensitive to contamination like wine
What type of fermentation is cheese?
lactic acid fermentation
why do we use a starter culture in the dairy fermentations
because it is hard to make the conditions favorable for the LAB to ovecome the other microorganisms.
the amylolytic fermentations uses molds like ____
aspergillus oryzae
The proteolyitic fermentations uses molds like ____
rhizopus oryzae
penicillum can be used in _____ fermentation on the rind of soft cheese
proteolytic
What is glacial acetic acid?
the name for water free acetic acid that is used in laboratories
Can you give the definition of AAB?
A group of Gram-negative bacteria that carry out oxidative fermentation to produce acetic acid from ethanol in a fermentation process.
Clostridium and Acetobacterium can convert ____ to a ____ without ____ and _____
sugar acetic acid oxygen ethanol
These acetogenic (bacteria that produce acetic acid anaerobically) bacteria produce acetic acid from one carbon compounds including methanol or carbon monoxide, and hydrogen:
clostridium and acetobacterium
why is the metabolism of AAB (oxidative fermentation) is somewhat unique?
because they accumulate the oxidized substrates and then use the accumulated products later
____ and ____ are only able to use ethanol
Acetobacter Komagataeibacter
____ can use several sugars or sugar alcohols such as D-glucose, D-sorbitol, and glycerol in addition to ethanol
Gluconobacter
in what kind of environment will you find AAB?
in sugar rich environments
to what kind of environment the AAB are well adapted ?
1- high in sugar 2- hihg in sugar alcohol 3- high in alcohol
why does the anaerobic fermentation of sugar into acetic acid by acetogenic bacteria is a slower way of making acetic acid than the aerobic fermentation by AAB ?
Intuitively it would seem that this a quicker process since there is no ethanol intermediate, but these bacteria cannot tolerate the accumulating acetic acid, thus the process is much slower
AAB are obligate aerobes, anaerobes or falcultative aerobes
obligate aerobes
What can AAB oxidize?
- sugars 2. sugar-alcohols 3. ethanol
does AAB create CO2?
no but it create 2 H2O for every ethanol
what is overoxidation?
When strains of AAB oxidize acetic acid
Why is there a biphasic growth curve (diauxic growth curve) for AAB?
because of the overoxidation
why does a concentration of 3% ethanol at the begining of the fermentation will prevent the overoxidation?
because the acetic acid production will be too high and will kill the cells
what are the strains of AAB capable of oxidizing lactic acid into acetoin?
-gluconoacetobacter -acetobacter
What are the strains used for the surface static process?
acetobacter
What are the strains used for the submerged process
komagateibacter
what is the type of acetic acid fermentation that leads to a higher concentration of acetic acid?
submerged process
what is the general stress protein assossiated with th epreventation of aggregation of misfolded proteins giving them the chance to refold
the GroES-GroEL chaperone
Expression of this system is linked to ethanol and not acetic acid
DNak-DnaJ-GrpE
Expression of this system is linked to ethanol and acetic acid
GroES-GroEL
what strain of AAB have efflux pumps
komagateibacter
•Nata de Coco is composed of bacterial cellulose by _____ at the liquid-air interface of coconut water
Komagataeibacter xylinus
What kind of AAB is generally found in kombucha?
Gluconacetobacter xylinus
•During wine production yeast is used as a starter culture and sulfur dioxide is used as _____
an antibacterial
how can you reduce the spoilage of wine by AAB?
the sulfure dioxide and the camben crush tablets
