Fermentation yields

Certain factors and product precursors are occasionally added to various fermentation media to iacrease product formation rates, the amount of product formed, or the type of product formed. Examples iaclude the addition of cobalt salts ia the vitamin fermentation, and phenylacetic acid and phenoxyacetic acid for the penicillin G (hen ylpenicillin) and penicillin V (phenoxymethylpenicillin) fermentations, respectively. Biotin is often added to the citric acid fermentation to enhance productivity and the addition of P-ionone vastly iacreases beta-carotene fermentation yields. Also, iaducers play an important role ia some enzyme production fermentations, and specific metaboHc inhibitors often block certain enzymatic steps that result in product accumulation. 

The production of elfamycins is described in the references cited in Table 1. Fermentation yield improvements with aurodox (1, R = CH ) proved difficult because of feedback inhibition (48). Aurodox-resistant strains (49), however, responded positively to conventional mutagenic methods leading to yield increases from 0.4 to 2.5 g/L (50). Scale-up of efrotomycin (7, R = CH ) fermentations were found to be particularly sensitive to small changes in sterilization conditions of the oil-containing medium used (51). 

The potential usefulness of elfamycins as growth promoters and feed-conversion enhancers is now generally recognized. Low original fermentation yields and difficulties in yield improvements discouraged early attempts to develop aurodox ( 1, R = CH ) and mocimycin (kirromycin) (1, R = H) commercially. 

Synthesis. One consequence of the discovery of the carbapenem natural products has been the development of new synthetic methods, the impetus for which was provided by the exceptional antibacterial potential of the compounds coupled with the extremely poor fermentation yields. Only chemical synthesis could provide the quantities of MK 0787 (18) necessary for clinical trials and commercial production. 

After the end of the fermentation (28 hours) the culture broth is filtered off by suction over a large suction filter. The mycel residue is washed with water several times. The filtrate is extracted three times, each time with 10 liters of methyl isobutyl ketone. The extract is concentrated under vacuum in a circulating evaporator and in a round flask carefully dried under vacuum. The residue is crystallized from acetone/isopropyl ether. The melting point is 157°-158°C (fermentation yield = 60%). The pure product yield obtained after a second crystallization and chromatography of the mother liquor on silica gel amounts to 53% of the theoretical. 

As a result, the partial breakdown of the organic matter by fermentation yields organic products with a low molecular weight, e.g., VFAs, along with C02. Compared with the aerobic respiration, the fermentation is inefficient however, these fermentation products can to some extent, and in addition to fermentable substrate, be used by the sulfate-reducing bacteria that make use of sulfate as the terminal electron acceptor (Nielsen and Hvitved-Jacobsen, 1988). In the absence of sulfate, the methanogenic bacteria utilize the low molecular... 

A paper by Kasprow et al.42 is important because it shows the realization that starting materials need to be analyzed on a routine basis just as with reaction products. Kasprow et al. discuss the correlation of fermentation yield with the yeast extract composition as seen by NIR. Using PLS for the correlations, models were constructed with a correlation of 0.996 and a standard error of 1.16 WSW. The authors used the models to predict yields, using different lots of yeast, and were quite satisfied with the results. 

Optimal fermentation parameters have been well established and air-lift, stirred tank, and hollow fibre systems have all been used. At commercial scale, fermentation volumes in excess of 1000 litres can be used, which can yield 100 g or more of final product. While hybridoma growth is straightforward, production levels of antibody can be quite low compared with ascites-based production systems. Typically, fermentation yields antibody concentrations of 0.1-0.5 mg/ml. Removal of cells from the antibody-containing media is achieved by centrifugation or filtration. An ultrafiltration step is then normally undertaken in order to concentrate the filtrate by up to 20-fold. 

P.-J. Maequer pointed out in his Dictionary of Chemistry (1778) that when plants are decomposed without combustion, acidic substances such as tartar and potassium acid oxalate are produced, that plants from which these acidic substances have been removed by extraction or distillation yield much less vegetable alkali than they otherwise would that by ignition tartar can be converted almost completely to this alkali (potassium carbonate) that the alkali in vegetable ash is therefore produced by the combustion of this acidic substance that decayed wood, in which the plant acids have been destroyed by fermentation, yields scarcely any alkali (as Boerhaave had observed) and that plants containing little or no acid yield on combustion little or no vegetable alkali (5). 

Assumptions nine 120.00- L batch fermenters yield 0.15 kg L-PHE/kg glucose 80% recove... 

Penicillin is but one of a series of closely related compounds isolated from fermentation broths of Penicillium notatum. This compound, also known as penicillin G (1-1) or benzyl penicillin, is quite unstable and quickly eliminated from the body. Initial approaches to solving these problems, as noted above, consisted of preparing salts of the compound with amines that would form tight ion pairs that in effect provided a controlled release of the active dmg. Research on fermentation conditions aimed at optimizing fermentation yields succeeded to the point where penicillin G or penicillin V (26-1), in which the phenylacetyl group is replaced by phenoxyacetyl, is now considered a commodity chemical. Another result of this research was the identification of fermentation conditions that favored the formation of the deacylated primary amine, 6-aminopenicillanic acid (2-4) or 6-APA, a compound that provided the key to semisynthetic compounds with superior pharmaceutical properties than the natural material. An elegant procedure for the removal of the amide side chain proved competitive with 6-APA from fermentation. This method, which is equally applicable to penicillin V, starts by conversion of the acid to the corresponding silyl ester (2-1). Treatment of that compound with phosphoms pentachloride in the... 

Fermentations Yield a Variety of Common Foods and Industrial Chemicals... 

Oxidative phosphorylation produces most of the ATP made in aerobic cells. Complete oxidation of a molecule of glucose to C02 yields 30 or 32 ATP (Table 19-5). By comparison, glycolysis under anaerobic conditions (lactate fermentation) yields only 2 ATP per glucose. Clearly, the evolution of oxidative phosphorylation provided a tremendous increase in the energy efficiency of catabolism. Complete oxidation to C02 of the coenzyme A derivative of palmitate (16 0), which also occurs in the mitochondrial matrix, yields 108 ATP per palmitoyl-... 

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). 

The yield of ATP (31/ mol/mol of glucose) is the highest we have discussed giving an efficiency of 50%. Another fermentation yields butanol, isopropanol, ethanol, and acetone. 

The production of elfamyans has been described in the literature. Fermentation yield improvements with aurodox has proved difficult... 

Ethanol (gal/bu) = Dry Mass Yield (lb/bu corn) x Carbohydrate Yield (lb/lb biomass) x 1.11 (lb free sugar/lb anhydrous sugar j x Fermentation Yield (lb ethanol/lb fermented sugar j 6.58 (lb ethanol/gal ethanol)... 

Szambelan, K., Nowak, J., and Chrapkowska, K.J., Comparison of bacterial and yeast ethanol fermentation yield from Jerusalem artichoke (Helianthus tuberosus L.) tuber pulp and juices, Acta Scientiarum Polonorum Technologia Alimentaria, 3, 45-53, 2004a. 

It is among the most capable of invertebrate anaerobes, the helminths and the marine bivalves, that we find the best examples of alternative fermentation pathways. Many of these have been reviewed several times elsewhere, so only a brief summary will be considered here. Current concepts view the organization of anaerobic metabolism as a series of linear, and loosely linked, pathways. The most important of these, aside from classical glucose — lactate fermentation (yielding 2 moles ATP per mole glucose) are summarized by Hochachka and Somero (1984) as follows (see chapter 2) ... 

Table 12.1 Fermentation yield improvement of NPI-0052 in shake flask and laboratory fermenter.

Nogueira et al. (2005) evaluated the alcoholic fermentation of the aqueous extract of apple pomace. Apple juice, pomace extract, and pomace extract added with sucrose provided after fermentation 6.90%, 4.30%, and 7.30% ethanol, respectively. A fermentation yield of 60% was obtained when pomace extract was used, showing that it is a suitable substrate for alcohol production. 

An increase in dark anaerobic hydrogen fermentation yields through metabolic engineering and other molecular and physiological techniques and... 

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