Bacteria, acetic acid characteristics

Trcek, J., Toyama, H., Czuba, J., Misiewicz, A., and Matsushita, K. 2006. Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria. Applied Microbiology and Biotechnology 70 366-373. 

Table 8.2 Important characteristics of brewery-related acetic acid bacteria...

Another characteristic of wines made from grapes affected by noble rot is their relatively high volatile acidity level. Its origin can be accidental, due to the presence of lactic acid bacteria in juice and especially acetic acid bacteria on grapes. Yeasts also form some volatile acidity, due to the corresponding fermentation difficulties of these juices (Section 2.3.4). 

Characteristics of the intermediate type strains. Agric Biol Chem 31 724-737 Asai T (1935) Taxonomic study of acetic acid bacteria and allied oxidative bacteria in fruits and a new classification of oxidative bacteria. Nippon Nogeikagaku Kaishi 11 674-708 (in Japanese) Asai T (1968) Acetic acid bacteria classification and biochemical activities. University of Tokyo Press, Tokyo... 

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). 

Table 4.1 Some important characteristics of dinitrogen-fixing acetic acid bacteria (AAB)...

Trcek J, Barja F (2015) Updates on quick identification of acetic acid bacteria with a focus on the 16S-23S rRNA gene internal transcribed spacer and the analysis of cell proteins by MALDI-TOF mass spectrometry. Int J Food Microbiol 196 137-144 Trcek J, Raspor P, Teuber M (2000) Molecular identification of Acetobacter isolates fiom submerged vinegar production, sequence analysis of plasmid pJK2-l and application in development of a cloning vector. Appl Microbiol Biotechnol 35 1899-1901 Trcek J, Toyama H, Czuba J, Misiewicz A, Matsushita K (2006) Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria. Appl Microbiol Biotechnol 70(3) 366-373... 

This section is completed with a brief review of the synthesis and properties of this epimer (20) of the precursor of thiazole in bacteria. This pentulose is conveniently accessible by an unconventional route (Scheme 19). Methyl 2,3 4,6-di-O-isopropylidene-a-D-mannopyranoside, readily available from methyl ot-D-mannopyranoside, is converted to the ketonic glycoside by butyllithium in 91% yield, following a method first published by Klemer and Rodemeyer43 and scaled up by Horton and Weckerle.44 This was converted by means of lithium hydroxide in a water-ether mixture into 3,5-0-benzylidene-l-deoxy-D-eryf/iro-2-pen-tulose in 55% yield. Hydrolysis to the free pentulose (20) proceeded in 73% yield in aqueous acetic acid. This product was obtained as a syrup with a characteristic absorption band at 1705 cm 1 as a film. Thus, there is a fair proportion of the open-chain ketone under these conditions, as with the D-threo epimer.45... 

At the same time, acetic bacteria are capable of esterifying the acetic acid that they form, producing ethyl acetate. The latter is responsible for the organoleptic characteristics of acescence, characterized by a very unpleasant, suffocating odor and an equally nasty impression of harshness and burning on the finish. The perception threshold of ethyl acetate (150 mg/1) is much lower than that of acetic acid (750 mg/1). 

The first members of the carboxylic acid series are colorless liquids with sharp or unpleasant odors. Acetic acid, which constitutes about 4% to 5% of vinegar, provides the characteristic odor and flavor. Butyric acid gives rancid butter its disagreeable odor, and the goat acids (caproic, caprylic, and capric in Table 10.1) smell like goats. 3-Methyl-2-hexenoic acid, produced by bacteria, is responsible for the offensive odor of human armpits. Table 10.3 lists some physical properties of selected carboxylic acids. 

Acids and bases are important substances in health, industry, and the environment. One of the most common characteristics of acids is their sour taste. Lemons and grapefruits are sour because they contain organic acids such as citric and ascorbic acid (vitamin C). Vinegar tastes sour because it contains acetic acid. We produce lactic acid in our muscles when we exercise. Acid from bacteria turns milk sour in the production of yogurt and cottage cheese. We have hydrochloric acid in our stomachs that helps us digest food. Sometimes we take antacids, which are bases such as sodium bicarbonate or milk of magnesia, to neutralize the effects of too much stomach acid. 

Characteristic flavouring substances of fermented dairy products are metabolites of lactic acid bacteria, especially biacetyl, acetaldehyde, dimethylsulfide, lactic and acetic acids, various aldehydes, ketones and esters. An important product is carbon dioxide. The acetaldehyde content in good quality yoghurts is 13-16 M-g/kg, while the biacetyl content is about four times higher. 

In bacteria, most fatty acids have 14 to 20 carbon atoms and are saturated or mono-unsaturated. Lactic acid bacteria also contain a characteristic cyclopropanic acid lactobacillic acid (cw-11,12-methylene-octodecanoic). Table 4.1 lists the principal fatty acids of lactic acid bacteria found in wine—notably Oenococcus oeni (Lonvaud-Funel and Desens, 1990). Malonyl CoA and acetate condense to form fatty acids with an even number of carbon atoms. For an odd number of carbon atoms, fatty acids are synthesized by the condensation of malonyl CoA and propionate. Anaerobic bacteria synthesize unsaturated acids by the action of a dehydratase on hydroxydecanoate which is formed by the addition of a malonyl unit on an octanoic acid molecule. 

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