Media acetic acid bacteria

The ability of 40 strains of acetic acid bacteria isolated from grape must and wine to produce biogenic amines was screened in synthetic medium and wine (Landete et al. 2007b), but no positive results were obtained. No further mention regarding the formation of biogenic amines by acetic acid bacteria was found in the literature. 

Acetic acid bacteria (AAB) are known for their ability to oxidize different substrates containing ethanol into various types of vinegar (Trcek, 2005). Substrates used as energy sources include glucose, ethanol, lactate, or glycerol. Most of these compounds are not completely oxidized into COz and HzO and many metabolites, such as acetic acid, may be accumulated in the growth medium. AAB are commonly found in nature and acetic... 

Williamson s deep-liver medium Contains yeast extract, liver extract, casein hydrolysate, glucose and pot. monohydrogen phosphate. Encourages some acetic acid bacteria and Hafnia. 

Williamson s medium A Contains beer, yeast extract, citrate-phosphate buffer. Supports acetic acid bacteria. 

Like above but contains beer and agar. Contains inter alia bile salts and neutral red indicator. Reasonably selective for brewery enterobacteria. Hafnia takes an extra day to grow at 25°C (77°F) on solid medium. Contains inter alia, ethanol and indicator (powdered chalk might be added). Suppresses most brewery microorganisms except acetic acid bacteria. 

Wieme AD, Spitaels F, Aerts M, De Bruyne K, Van Landschoot A, Vandamme P. Effects of growth medium on matrix-assisted laser desorption-ionization time of flight mass spectra a case study of acetic acid bacteria. Appl Environ Microbiol. 2014 80 1528 8, 12... 

Gluconobacter growing on GYCM over time (3 to 5 weeks) produces water-soluble brown pigments, which are not seen in the case of any similarly cultivated Acetobacter species. Grown on this medium, Acetobacter will produce clear zones or halos around colonies because the acid being produced will neutralize the CaCOs. Unlike the lactic acid bacteria, acetic acid bacteria are obligate aerobes and so it is necessary to use spread plates. 

The isolation of acetic acid bacteria from grape must or wine is carried out by culture on a solid nutritive medium. The composition of the medium varies, depending on the researcher. Nevertheless, taking into account their nutritional demands. 

When the composition, especially the carbon sources, of the medium in the enrichment procedure is changed, the selective isolation of acetic acid bacteria can be expected. In fact, strains of Asaia bogorensis and Asaia siamensis were first isolated by the use of o-sorbitol or dulcitol instead of o-glucose (Yamada et al. 2000 Katsura et al. 2001). Several kinds of media employed for the enrichment procedure result in the effective isolation of acetic acid bacteria (Lisdiyanti et al. 2003b Suzuki et al. 2010). Instead of the pH 3.5 medium, the pH 4.5 medium containing 0.03 % acetic acid (v/v) can be used (Yamada et al. 1976). 

To select acetic acid bacteria from a number of the strains isolated, it is suitable to test the strains for growth on a pH 3.5 medium, which contains, for example, 1.0 % D-glucose (w/v), 0.5 % ethanol (99.8 %) (v/v), 0.3 % peptone (w/v), and 0.2 % yeast extract (w/v) the pH is adjusted to 3.5 with hydrochloric acid (Yamada et al. 1999). A pH 4.0 medium can be used for the growth test. If a certain strain is an acetic acid bacterium, appropriate growth can be seen. If the pH of the medium is adjusted to 4.5, bacteria other than acetic acid bacteria sometimes can grow. 

Although the consumption of soybean protein as a food ingredient has increased, its characteristic beany flavor has hindered its wide utilization. Medium-chain aldehydes such as n-hexane appear to be mainly responsible for the objectionable flavor of soybean products. The effective removal of n-hexane from soybean protein by acetic acid bacteria was demonstrated (Adachi et al. 1980). These effective acetic acid bacteria were A. aceti and G. suboxydans Gluconobacter oxydans) (Kobayashi et al. 1992). 

In addition, the surface of AarA protein is more basic than that of E. coli, so it is thought that the enzyme functions stably even at lower pH (Francois et al. 2006). Furthermore, citrate synthase purified from Gluconacetobacter europaeus (Komagataeibacter europaeus) was also shown to be stable in the presence of acetic acid (Sievers et al. 1997). It appears reasonable that the enzymes of acetic acid bacteria are intrinsically resistant to inactivation by low pH and functionally adapt to low pH. It was shown by proteomic analysis that aconitase was induced with acetic acid in a medium (Nakano et al. 2004). The transformant that highly expressed aconitase showed higher productivity of acetic acid than the wild-type strain, which has lower acetic acid tolerance (Fig. 10.6). 

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