Propionate determining factors

Note The relative response factor for 8-tocopheryl propionate and for 3- plus y-tocopheryl propionates has been determined empirically to be the same as that for a-tocopheryl propionate. 

In Figure 2.15, an example is given of the modified simplex procedure for the determination of fluticasone propionate with flow injection analysis (104). The initial simplex is formed by points 1, 2, and 3. Points 4-14 represent the sequentially selected vertices. Point 6 seems to be situated close to the optimum because it is maintained in many simplexes. It is observed that again, as in the classic procedure, the simplexes circle around the optimum, but here also their size decreases as the procedure continues. To optimize three or more factors, the simplex procedures can be generalized, as described in Reference 8. 

In the absence of oxygen, microorganisms convert pyruvate and/or acetyl-CoA to a number of different organic acids or alcohols, which are then excreted from the cell as a waste product (Figures 7.1 and 7.3). The most common products formed are acetone, acetic acid, n-butanol, butyric acid, 2,3 butanediol, ethanol, isopropanol, lactic acid, propionic acid and succinic acid (Shuler and Kargi, 2002). All of these compounds have industrial importance as bulk chemicals, precursors for other products, or fuels. The determination of which of these compounds is formed is dependent on a number of factors, including the species of organism, the redox balance, media pH, nutrient composition and temperature of the reactor. 

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