Organic acid-producing

It should be noted that apart from a passing reference to natural selection of wild-types with enhanced specific properties, the genetics of organic acid producing micro-organisms is beyond the scope of this chapter. 

Table 5.1 Example of organic acids produced commercially by micro-organisms organic adds considered in this chapter are labelled with. A related add, a-oxoglutaric acid, is easy to produce microbiologically but has no current end use succinic acid is produced chemically. Amino adds are beyond the scope of this chapter.

Increase of reservoir permeability and widening of the fissures and channels through the etching of carbonaceous rocks in limestone reservoirs by organic acids produced by anaerobic bacteria... 

Lactic acid is one of the major organic acids produced by fermentation. AimuaUy about 35 000 tonnes are produced this way [56]. The work on NF-based membrane fermentors for the production of organic acids has been started with the observation that lactic acid retention of RO membranes shows a strong pH-depen-dence [57-59]. For selective removal of lactic acid a low pFI is necessary, however, this reduces the lactic acid productivity to about 1 g Compared with UF-... 

Organic acids produced by the organisms can cause a drop in the pH of a formulation, resulting in physical instability. These same organic acids, along with other metabolic byproducts of the microorganisms, can also impart unwanted odours and colours which alter the appearance and absorption of the paint. Incorporation of a preservative is recommended to prevent these problems from occurring. 

Reactions with acetic and other organic acids produce corresponding salts. 

Sodium hydroxide is a strong base. The most important reactions are the neutraliztion reactions with acids that form salts and water. Thus with sulfuric, hydrochloric, and nitric acids, the corresponding sodium salts are obtained when solutions are evaporated for crystallization. Neutralization with weak acids forms basic salts. Reactions with organic acids produce their soluble sodium salts. 

Kavouras, I.G. Mihalopoulos, N. Stephanou, E.G. (1998) Formation of atmospheric particles from organic acids produced by finests. Nature, 395,683-6. 

Kavouras, I. G N. Mihalopoulos, and E. G. Stephanou, Formation of Atmospheric Particles from Organic Acids Produced by Forests, Nature, 395, 683-686 (1998). 

Table 4. Main Organic Acids Produced by Microorganisms 48 ...

Citric Acid. Citric acid, whose structure is shown below, is the most important organic acid produced by means of fermentation. 

Hence it can only be sustained beyond reproduction if losses remain acceptably low for example, roots can sustain terrestrial plants only if they manage to sequester the essential elements by delivering just a part of the organic acids produced primarily by photosynthesis from COj, N oxoanions rather than aU of it. The theoretical minimum here would be 3% the above ratio w 200 combines with citrate containing... 

The diaminobenzenes (phenylenediamines) are prepared by reduction of 1,3-dinitrobenzene and 2- and 4-nitroanilines. o-Phenylenediamine is of value in the synthesis of a range of nitrogen heterocycles. Thus reaction with organic acids produces benzimidazoles (8). With 1,2-dicarbonyl compounds, quinoxalines (9) are produced. Treatment with nitrous acid results in diazotization of one amino group followed by immediate cyclization to give benzotriazole (10). 

Table 25.2 Examples of vitamins, amino acids, antibiotics and organic acids produced by microorganisms ...

Of the two major weak organic acids produced by LAB (acetic and lactic acid), acetic acid is the strongest inhibitor because of its higher dissociation constant (pKa = 4.75) as compared to lactic acid (pKa = 3.08) at a given molar concentration and pH level (Eklund, 1983 Holzapfel et al., 1995 Ouwehand, 1998). 

Chapter four Microbial organic acid producers... 

Fumaric acid is another organic acid produced by Rhizopus, in particular Rhizopus stolonifer. The presence of fumaric acid has also been found to arise from the addition of synthetic malic acid and is sometimes considered as an index of adulteration when confirmed by analysis of D-malic acid (not present in malic acid from natural sources) (Trifiro et al., 1997). 

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