Acetobacter species

Natural aroma chemicals Production via fermentation or enzymatic treatment Oxidation of 2-methylbu-tanol to 2-methylbutyric acid via Acetobacter species... 

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). 

Various microorganisms under certain conditions are able to excrete intermediate products (organic acids) from or closely related to the tricarboxylic acid cycle (Fig. 3, Table 4). For example, Clostridium produces acetic acid and butyric acid, Lactobacillus and Streptococcus species produce lactic acid, Acetobacter species acetic, gluconic, and ketogluconic acids, and Pseudomonas species 2-ketogluconic and a-ketoglutaric acids. 

Vinegar Cider, wine Acetobacter species Worldwide... 

In 1973 the structure (157) or (158) was proposed for a C35 hopane derivative, bacteriohopanetetrol, from the bacterium Acetobacter xylinum. Structure (157) is attractive as a precursor for the extended hopane derivatives obtained from geological sources (see Vol. 3, p. 228 and Vol. 5, p. 145). Rohmer and Ourisson have now confirmed"" the validity of (157) and have shown the presence of both (22R)- and (225)-epimers. Periodate cleavage of the tetrol followed by sodium borohydride reduction and acetylation afforded the epimeric acetates (159) identical with synthetic samples prepared from diploptene (160). A range of Acetobacter species and... 

Isobutyric acid Isobutanol Acetobacter species Buttery, cheesy... 

Cells for Increasing Fermenter Efficiencies. The tower fermenter system used is described in Figure 3. Wort was used as the ethanol source, and an inociilum of an aggregating strain of Acetobacter species was prepared and added to the tower fermenter (2 litres capacity). When the level of acetic acid in the fermenter had reached about 3% w/v, the medium delivery pump was started and the flow rate adjusted to a level that gave almost complete conversion of the ethanol available into acetic acid. Undue haste in increasing the flow rate and also serious decrease or stoppage of the air flow caused the expected fall in conversion efficiency. Adjustment of the flow and aeration rate showed that a maximum V. E. of 0.82 could be attained (see Table I). 

There are four types of nanocellulose depending on their fabrication method bacterial cellulose, electrospun cellulose, microfibrillated cellulose (MFC) and whiskers of cellulose (nanorods). Bacterial cellulose is a nanomaterial derived from plant material by bacterial action in the presence of oxygen. Various strains of Acetobacter species [82,83] can be used to produce cellulose, although strains of pseudomonas, Achrobacter, Alcaligene, Aerobacter and Azotobacter [84] can also be used. The bacterial cellulose... 

Acetobacter species Produce acetic acid (vinegar) and ropiness. Aerobes so bmited to certain... 

In addition to plant-derived cellulose, cellulose can also be synthesised by bacteria such as from the Acetobacter species. By culturing cellulose-producing bacteria in the presence of natural fibres in an appropriate culture medium, bacterial cellulose is preferentially deposited in situ onto the surface of natural fibres. The introduction of bacterial cellulose onto natural fibres provides new means of controlling the interaction between natural fibres and polymer matrices. Coating of natural fibres with bacterial cellulose not only facilitates good distribution of bacterial cellulose within the matrix, but also results in an improved interfacial adhesion between the fibres and the matrix. This enhances the interaction between the natural fibres and the polymer matrix through mechanical interlocking. 

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. 

Fig. 22.2. Oxidation of ethanol to acetic acid by Acetobacter species (according to Rehm, 1980)...

Table 7.1. Principal distinctive characteristics of Acetobacter species (Swings, 1992 Sieves et al., 1992)...

Kennedy JF, Humphreys JD, Barker SA, Greenshields RN (1980) Application of living immobilized cells to the acceleration of the continuous conversions of ethanol (wort) to acetic acid (vinegar) by hydrous titanium (IV) oxide-immobilized Acetobacter species. Enz Microbiol Technol 2 209-216... 

Ktmdo K, Ameyama M (1958) Carbohydrate metabolism hy Acetobacter species Part 1. Oxidative activity for various carbohydrates. Bull Agric Chem Soc Jpn 22 369-372 Leifson E (1954) The flagellation and taxonomy of species of Acetobacter. Antonie Van Leeuwenhoek 20 102-110... 

The growth of Acetobacter species on ethanol results in the accumulation of acetate, which is then completely oxidized by the phenomenon termed acetate overoxidation. The sequential oxidation of ethanol and acetate leads to a diauxic growth profile that is characterized by acetate accumulation in the first exponential growth phase and complete oxidation of the accumulated acetate in the secrnid exponential phase (Saeki et al. 1997). However, in some conditions, ethanol is oxidized to acetate both in the periplasm, by membrane-bound PQQ-dependent ADH and aldehyde dehydrogenase (ALDH), and in the cytoplasm, by soluble NAD (P) -dependent ADH and ALDH. These conditimis are unfavorable for vinegar production because acetate generated in the cytoplasm tends to be rapidly metabolized via the tricarboxylic acid (TCA) cycle. 

Ameyama M, Kondo K (1958a) Carbohydrate metabolism by Acetobacter species. Part III. Isolation and identification of D-lyxuronic acid on glucose oxidation by A. melanogenum. Bull Agric Chem Soc Jpn 22(6) 380-386... 

Kouda T, Yano H, Yoshinaga F (1997) Effect of agitator configuration on bacterial cellulose productivity in aerated and agitated culture. J Foment Bioeng 83 371-374 MacCormick CA, Harris JE, Jay AJ, Ridout MJ, Colquhoun U, Morris VJ (1996) Isolation and characterization of a new extracellular polysaccharide liom an Acetobacter species. J Appl Bacteriol 81 419-424... 

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