An Overview on the Biological Production of Vinegar

Acetic Acid Bacteria (AAB)

TheȱninthȱeditionȱofȱBergey’sȱManualȱofȱSystematicȱBacteriologyȱclassifiedȱtheȱ

acetic acid bacteria (AAB) in the family Acetobacteriaceae and Gluconobacter.

AAB are Gram-negative or Gram-variable bacteria, with ellipsoidal to rod-

shapedȱmorphologies,ȱbeingȱmotileȱdueȱtoȱtheȱpresenceȱofȱflagella,ȱwhichȱ

could be either peritrichous or polar. Their size variesbetween 0.4-1 μm

wide and 0.8-4.5 μm long. They are observed as individual cells, in pairs

or in chains. They show a strict aerobic metabolism with oxygen as the

terminal electron acceptor, and are catalase positive and oxidase negative

(Gonzalez et al., 2004).

Gullo and Giudici (2008) reported that the AAB were present in the

environment and in the raw material, but they cannot grow during

alcoholic fermentation because of the anaerobic conditions. When the

alcoholic liquid was exposed to oxygen, the AAB started their growth on

the surface. Du Toit and Pretorius (2002) reported that most AAB growth

was observed between pH 5.4 - 6.3, but they also could grow at pH values

lower than 4. They also reported that AAB could also be isolated at pH

values of 2.0-2.3 in media containing acetate, if they were aerated. The

optimal temperature for their growth was 25-30 o C, but their growth was

also observed between 38-40 o C and weakly at temperatures as low as 10 o C.

Yamada and Yukphan (2008) studied that AAB were usually found in

substrates containing sugar and/or ethanol. These substrates include

fruits,ȱflowers,ȱfoodȱandȱfermentedȱbeverages,ȱsuchȱasȱfruitȱjuices,ȱwine,ȱ

cider, beer, cocoa and vinegar.

Gullo et al., ȱ(2006)ȱreportedȱclearȱgrowthȱdifferencesȱbetweenȱAABȱspeciesȱ

isolatedȱfromȱfruits,ȱflowersȱandȱfermentedȱfoods,ȱandȱtheyȱhadȱdisplayedȱ

differingȱ abilitiesȱ toȱ growȱ usingȱ differentȱ cultureȱ mediaȱ dependingȱ onȱ

the available nutrients. Results showed that there was a poor recovery on

synthetic culture media due to the lack of a suitable synthetic media, as not

all synthetic media equally support the growth of AAB and could even be

selective among strains. However, considerable progress in AAB isolation

had been made with the development of various culture media.

Garcia-Garcia et al., (2009) conducted studies on the acetous fermentation

of ethanol into acetic acid by acetic acid bacteria belonging to the family

Acetobacteriaceae and the genera Acetobacter and Gluconobacter . The total

chemical reaction that took place was as follows:

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