Other organisms

Rhizopus oryzae is another important fungus involved in the production of organic acids in industrial fermentation. It is widely used to produce L-lactic acid as well as other organic acids. R. oryzae, produces only one stereospecific product (L-lactic acid), and not a racemic mixture (Wang et al., 2005). Much research has been done on the mechanism of lactic acid 

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). 

In 2006 Saccharomyces cerevisiae was found for the first time to be able to produce large amounts of lactic acid, which is related to its ability to maintain a higher pH (Valli et al., 2006). Contrary to this finding, various yeasts are known to produce low amounts of acetic acid (Trifiro et al., 1997). 

Abarca, M.L., Accensi, F., Cano, J., and Cabanes, F.J. 2004. Taxonomy and significance of black aspergilli. Antonie Van Leeuwenhoek 86 33-49. 

Safety of industrial lactic acid bacteria. Journal of Biotechnology 68 171-178. 

Another approach to determine the magnitude of lead pollution in Mexico City has been the use of sentinel organisms such as dogs and pigeons (Rosiles 1987a). Lead was determined in different organs and body fluids however, although the author reported a correlation of lead levels with the zone where the animal was 

Estadio Azteca Carr. Mex. Toluca Churubusco-Ermita Xochimilco Milpa Alta 

From the available data it is evident that many more studies are needed on this subject in order to evaluate properly the magnitude of the presence of lead in organisms and its possible impact on the health of the Mexican population and on the environment. 

The results of these investigations suggest that caution should be exercised in interpreting not only the results of toxicity assays in which such organisms are employed but also data accumulated in monitoring studies that may not have taken into account the existence of metabolites. 

Resistance of house flies (Musca domestica) to DDT was attributed to its transformation to the nontoxic DDE, and the enzyme that carries the dehydrochlorination has been characterized in DDT-resistant flies (Lipke and Kearns 1959a,b). The herbicide alachlor is transformed by chironomid larvae by O-demethylation followed by loss of the chloroacetyl group to produce 2,6-diethylaniline 

The metabolism of xenobiotics by both terrestrial and sediment-dwelling biota has been studied, and provides illustrations of the importance of uptake by food or by sorbed sediment. Some examples of metabolism by terrestrial biota include the following. 

The uptake and elimination of benzo[a]pyrene by the terrestrial isopod Porcellio scaber have been investigated (van Brnmmelen and van Straalen 1996), and 1-hydroxypyrene was identified among the metabolites of pyrene in this organism (Stroomberg et al. 1996). 

There remain a number of anaerobic protists that lack classical mitochondrial organelles. Some of these protists, such as the oxymonads and retorta-monads, were originally classified as Archezoa (Cavalier-Smith 1983), but consideration of their likely phylogenetic positions (Fig. 10.2) argues against 

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Tetracyclines are broad-spectrum antibiotics. effective against Gram-positive and Gram-negative bacteria, also against Rickettsiae (typhus fever) and certain other organisms. 

This method is also applicable to other organic compounds for which one should refer to the original publication. The average error is around 2%. 

In the standard method, the metal enclosure (called the air chamber) used to hold the hydrocarbon vapors is immersed in water before the test, then drained but not dried. This mode of operation, often designated as the wet bomb" is stipulated for all materials that are exclusively petroleum. But if the fuels contain alcohols or other organic products soluble in water, the apparatus must be dried in order that the vapors are not absorbed by the water on the walls. This technique is called the dry bomb" it results in RVP values higher by about 100 mbar for some oxygenated motor fuels. When examining the numerical results, it is thus important to know the technique employed. In any case, the dry bomb method is preferred. 

Scientific, and especially chemical, information is becoming increasingly available on the Internet. This has the advantage that the information is accessible to other users. Additionally, the data formats (HTML, PDF, GIF, etc.) that are used are restricted to the most important ones to provide standards that are readable worldwide. Unfortunately, however, much of the information on the Internet is not reviewed or verified by other organizations as is the case in the primary literature. Thus, the quality of the information is extremely variable. 

Pancreatic lipase pancreas fats and other organic esters organic acid and alcohol (often gly ceroi) 7-0... 

Heat a little pseudo-saccharin chloride with excess of the anhydrous alcohol in a test-tube until hydrogen chloride is no longer evolved. Recrystallise from alcohol or other organic solvent. 

Mono- and di saccharides are colourless solids or sjrrupy liquids, which are freely soluble in water, practically insoluble in ether and other organic solvents, and neutral in reaction. Polysaccharides possess similar properties, but are generally insoluble in water because of their high molecular weights. Both poly- and di-saccharides are converted into monosaccharides upon hydrolysis. 

Phenyldiazonium chloride and other similar diazonium compounds are very soluble in water, are completely insoluble in ether and other organic solvents, and are completely dissociated in aqueous solution to organic cations and inorganic anions (e.g., chloride ions) a convenient formulation is therefore, for example, CjHjNj+CP. 

To determine the exact peroxide content of benzoyl peroxide (and of other organic peroxides) the following procedure may be employed. Place about 0 05 g. of the sample of peroxide in a glass-stoppered conical flask add 5-10 ml. of acetic anhydride (A.R. or other pure grade) and 1 g. of powdered sodium iodide. Swirl the mixture to dissolve the sodium iodide and allow the solution to stand for 5-20 minutes. Add 50-75 ml. of water, shake the mixture vigorously for about 30 seconds, and titrate the liberated iodine with standard sodium thiosulphate solution using starch as indicator. 

First, the use of water limits the choice of Lewis-acid catalysts. The most active Lewis acids such as BFj, TiQ4 and AlClj react violently with water and cannot be used However, bivalent transition metal ions and trivalent lanthanide ions have proven to be active catalysts in aqueous solution for other organic reactions and are anticipated to be good candidates for the catalysis of aqueous Diels-Alder reactions. 

Of all the work described in this thesis, this discovery is probably the most significant. Given the fact that the arene - arene interactions underlying the observed enantioselectivity of ftie Diels-Alder reactions described in Chapter 3 are also encountered in other organic reactions, we infer that, in the near future, the beneficial influence of water on enantioselectivity can also be extended to these transformations. Moreover, the fact that water can now be used as a solvent for enantioselective Lewis-add catalysed reactions facilitates mechanistic studies of these processes, because the number of equilibria that need to be considered is reduced Furthermore, knowledge and techniques from aqueous coordination chemistry can now be used directly in enantioselective catalysis. 

Frank Whitmore in the United States in the 1930s in a series of papers, generalized these concepts to include many other organic reactions. Carbocations, however, were generally considered to be unstable... 

Combustion in air is of course a chemical property of ethers that IS shared by many other organic compounds Write a balanced chemical equa tion for the complete combustion (in air) of diethyl ether... 

Suggest a reasonable mechanism for this reaction What other organic product is also formed ... 

Volatile analytes can be separated from a nonvolatile matrix using any of the extraction techniques described in Ghapter 7. Fiquid-liquid extractions, in which analytes are extracted from an aqueous matrix into methylene chloride or other organic solvent, are commonly used. Solid-phase extractions also are used to remove unwanted matrix constituents. 

Physical Properties. Furfuryl alcohol (2-furanmethanol) [98-00-0] is aHquid, colorless, primary alcohol with a mild odor. On exposure to air, it gradually darkens in color. Furfuryl alcohol is completely miscible with water, alcohol, ether, acetone, and ethyl acetate, and most other organic solvents with the exception of paraffinic hydrocarbons. It is an exceUent, highly polar solvent, and dissolves many resins. 

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