Acetobacter, vinegar fermentation

Sievers, M., Sellmer, S., and Teuber, M. 1992. Acetobacter europaeus sp. nov., a main component of industrial vinegar fermenters in central Europe. Systematic and Applied Microbiology 15 386-392. 

There are several types of acetic bacteria (Volume 1, Chapter 7) with different metabolic properties. These are responsible for serious problems due to acescence, sometimes called acetic spoilage . Wine is only affected by Acetobacter, or vinegar ferment. The main reaction consists of the oxidation of ethanol to produce acetic acid. In the presence of ethanol, this same bacterium may also esterify acetic acid to produce ethyl acetate. Acetic bacteria develop in the form of a white bloom that may take on various appearances. Prolonged development produces a viscous mass, known as vinegar mother . 

Slapsak N, Cleenwerck I, De Vos P, Trcek J (2013) Gluconacetobacter maltaceti sp. nov., a novel vinegar producing acetic acid bacterium. Syst Appl Microbiol 36 17-21 Sokollek SJ, Hertel C, Hammes WP (1998) Description of Acetobacter oboediens sp. nov. and Acetobacterpomorum sp. nov., two new species isolated from industrial vinegar fermentations. Int J Syst Bacteriol 48 935-940... 

Solieri L, Landi S, De Vero L, Guidici P (2006) Molecular assessment of industrial vinegar fermentation from traditional balsamic vinegar. J Appl Microbiol 101 63-71 Spitaels F, Li L, Wieme A, Balzarini T, Cleenwerck I, Van Landschoot A, De Vuyst L, Vandamme P (2014) Acetobacter lambici sp. nov., isolated from fermenting Lambic beer. Int J Syst Evol Microbiol 64 1083-1089... 

The sugars in fruits such as grapes are feimented by yeasts to produce wines. In winemaking, lactic acid bacteria convert malic acid into lactic acid in malolactic fermentation in fruits with high acidity. Acetobacter and Gluconobacter oxidise ethanol in wine to acetic acid (vinegar). 

In fermentation for the production of acetic acid, ethyl alcohol is used in an aerobic process. In an ethanol oxidation process, the biocatalyst Acetobacter aceti was used to convert ethanol to acetic acid under aerobic conditions. A continuous fermentation for vinegar production was proposed for utilisation of non-viable A. aceti immobilised on the surface of alginate beads. 

Acetobacter bacteria oxidatively convert wine to vinegar through an aerobic fermentation of ethanol (a primary alcohol) into acetic acid (a carboxylic acid) ... 

Whey does not lend itself to direct production of acetic acid by species of the genus Acetobacter. Furthermore, use of combined inocula of yeasts and Acetobacter species has not proved fruitful. However, Haeseler has described an operable procedure, in which an alcoholic followed by an acetic acid fermentation yielded a vinegar with satisfactory qualities (Marth 1974). 

A number of factors govern the composition of vinegar the nature of the raw material, the substances added to promote alcoholic fermentation and the growth and activity of Acetobacter, the procedure used for the acetification, and finally the aging, stabilization, and bottling operations. 

Various species and many strains of Acetobacter are used in vinegar production. Aeration rates, optimum temperatures and nutrient requirements vary with individual strains. In general, fermentation alcohol substrates require minimal nutrient supplementation while their addition is necessary for distilled alcohol substrates. 

Acetic acid is produced by oxidation of ethanol by Acetobacter organisms. It is either used in diluted form as vinegar or distilled to give neat (100 percent pure) acetic acid. For many centuries, acetic acid was produced only via the fermentation route. Since the advancement of the petrochemical industry, it is also produced synthetically, at least for industrial use. 

Vinegar (acetic acid) by aerobic fermentation of ethanol Acetobacter... 

Saeki, A. (1990). Studies on acetic acid fermentation. Ill continuous production of vinegar with immobilized Saccaromycodes ludwigii cells and immobilized Acetobacter aceti cells entrapped in calcium alginate gel beads. J. Jpn. Soc. Food Sci. 37, 722-725. 

For larger scales, shallow trays made of corrosion-resistant metal or plastic placed in portable trolleys may be used for efficient liquid-air contact. The trolleys are placed in a sterile room with frequent sterile air changes under closely controlled temperature and humidity conditions. Efficient air-liquid contact may also be obtained from a loosely packed, moist, solid medium permeated with air. For instance bran is used as the substrate for enzyme production by Aspergillus oryzal. Wine vinegar (acetic acid) is produced by trickling wine (basically ethanol in water) over a short tower of wood chips, which are used both as a support and to provide air to Acetobacter aceti [13] (Eq. 16.15). By law, the acetic acid (3-5% in water) in vinegar must be produced by fermentation, and not by petrochemical methods. 

Several other organic acids are also made commercially on a large scale by microbial techniques. Some of the better known examples of these are acetic acid (vinegar) via the metabolism of alcohol in water by Acetobacter aceti, and lactic acid (Eq. 16.33), produced by Streptococcus lactis fermentation of hexose sugars. 

The Acetobacter is, therefore, dependent on the yeasts for production of an oxidizable substance such as ethanol. Other organic acids may also be produced during this fermentation process. These are then converted to esters and may contribute to the odor, flavor, and color of the vinegar (FAO, 1998). 

Acetic acid fermentation Vinegar Grapes, potatoes. Acetobacter europeus... 

Adsorption of a biocatalyst onto a water-insoluble macroscopic carrier is the easiest and oldest method of immobilization. It may be equally well applied to isolated enzymes as well as to whole viable cells. For example, adsorption of whole cells of Acetobacter onto wood chips for the fermentation of vinegar from ethanol was first used in 1815 Adsorbing forces are of different types, such as van der Waals (London) forces, ionic interactions, and hydrogen bonding, and are all relatively weak. The appealing feature of immobilization by adsorption is the simplicity of the procedure. As a result of the weak binding forces, losses in enzyme activity are usually low, but desorption (leakage) from the carrier may be caused by even minor... 

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