Fermentation extractive alcoholic

Evaluation of Optimization Techniques for an Extractive Alcoholic Fermentation Process... 

Index Entries Extractive alcoholic fermentation optimization successive quadratic programming factorial design response surface methodology productivity. 

A general scheme of the extractive alcoholic fermentation proposed by Silva et al. (3) is shown in Fig. 1. The process consists of four interlinked units the fermentor (ethanol production unit), the centrifuge (cell separation unit), the cell treatment unit, and the vacuum flash vessel (ethanol-water separation unit). A detailed description of the process and mathematical model can be found in ref. 5. 

Hexose diphosphate was found by Harden and Young69 in cell-free alcoholic-fermentation liquors. In 1930, it was observed that addition of fluoride to fermenting-yeast extracts leads to an accumulation of 0-phospho-D-glyceronic acid,60 which is also a metabolite of muscle extracts.61 Attention was turned, therefore, to the pathway from hexose diphosphate to 0-phos-pho-D-glyceronic acid. In 1932, Fischer and Baer62 described the synthesis of D-glycerose 3-phosphate, and, in 1933, Smythe and Gerischer63 noted... 

The second half of the 1990s saw an increase in the use of dialysis (as a liquid-liquid extraction procedure). Its main advantage is the possibility of operating in an automatic mode by coupling a dialysis unit with an automatic injector, as demonstrated not only in HPLC analysis (17) but also in flow-injection determinations of reducing sugars in wines (18) and alcoholic fermentation broths (19). 

KI Tomlins, DM Baker, IJ McDowell. HPLC method for the analysis of organic acids, sugars, and alcohol in extracts of fermenting cocoa beans. Chromatographia 29(11/12) 557-561, 1990. 

The first-generation biofuels can be identified as ethanol, which was produced via the alcoholic fermentation of cereals, and hio-oil or biodiesel, which was extracted from seeds such as sunflower, rapeseed, or palm. The use of cereals and sunflowers was rejected by public opinion and some scientific environments, because their use for energy production conflicted with their use as foodstuffs. In fact, the diversion of cereals to the production of ethanol for transport has led to a rise in the price of flour and derived goods, especially in Mexico. The same situation has arisen for some bio-oils, such that the source was shifted to palm-oil which, essentially, is produced in Asian countries such as Malaysia. 

Development of serum-free medium has great value for large-scale biopesticide production. The latest formulations are serum-free, such as SF900II (GIBCO /Invitrogen) and EX-CELL (JRH Biosciences). Cell culture medium supplementation using yeast extract (usually from alcoholic fermentation processes), milk, or soy protein concentrates, can also be an alternative to decrease cell culture medium costs (more details can be found in Chapter 5). 

Solvent extraction has long been established as a basic unit operation for chemical separations. Chapter 7 summarizes the effects of temperature, pH, ion pairs, and solvent selection on solvent extraction for biomolecules. Solvent extraction of fermentation products such as alcohols, aliphatic carboxylic acids, amino acids, and antibiotics are discussed. Enhanced solvent extraction using reversed micelles and electrical fields are also discussed. Solvent-extraction equipment and operational considerations are adequately covered in this chapter. 

The catalytic action of living organisms, or rather of the proteins they contain, had received the beginnings of an explanation with the experiments of Payen and Persoz on malt amylase separation in 1833 and with J. J, Berzelius s catalyst theory in 1835. In 1897 Eduard Buchner demonstrated that a yeast extract could turn sucrose into ethyl alcohol, Fermentation took place without the presence of living organisms through enzymes. In this case zymase was the catalyst. 

During alcoholic fermentation, the degree of maceration is the first factor that affects the extraction of some compounds present in the grape skin, especially phenolic compounds, which are responsible for the color of the wine. However, not only does the maceration affect the extraction of polyphenols but also of other grape components, such as proteins, polysaccharides and, also, amino acids, which are precursors of biogenic amines. In most red wines, alcoholic fermentation takes place... 

Chalier et al. (2007), using mannoprotein at levels usually found in wines (150 mg/L), compared the effect of a whole mannoprotein extract (isolated from a synthetic medium subjected to alcoholic fermentation) to that of well characterized different mannoproteins fractions. From the four wine aroma compounds studied (isoamyl acetate, hexanol, ethyl hexanoate and /3-ionone), all except isoamyl acetate showed a decrease in volatility (up to 80%) when mannoproteins were present (Fig. 8F.3). They suggested that both the glycosidic and the peptidic parts of these macromolecules may be responsible for the interaction. They also found that the interactions of the whole mannoprotein extract Vs. mannoprotein fractions were different, suggesting that the conformational and compositional structure of these... 

The interactions between aroma compounds and macromolecules from yeast released during alcoholic fermentation (F) and autolysis (A) were studied by the headspace technique (11). The values of infinite dilution activity coefficients of volatile compounds were measured in a model wine with and without macromolecules at Ig/L (Table I). The volatility of ethyl decanoate stays constant in the presence of both extracts. For ethyl hexanoate and octanal, the F extract produces a significant (P< 0.01) decrease in the activity coefficient, by 12 and 8% respectively. Conversely F extract increases the volatility of isoamyl alcohol and ethyl octanoate by 6 and 19% respectively. The A extract increases the volatility of ethyl hexanoate by 6% and the volatility of ethyl octanoate by 15%. These results demonstrate the complex influence of macromolecules from yeast released during fermentation or autolysis on the volatility of aroma compounds. 

The production of aldehydes and alcohols from the hydrophobic amino acids has been studied primarily in yeast (147,148,149,154) since the fusel oils produced are significant secondary products of alcoholic fermentation (149). Also important are the studies of Morgan and coworkers on the malty flavor defect in milk which is produced by Streptococcus lactis var. maltigenes (155-161). This flavor is principally caused by 3-methylbutanal (155) which is produced by transamination of leucine to a-ketoisocaproate and decarboxylation (157). Labeling experiments showed that this compound is produced from leucine by tomato extract (9, 162, 163). The corresponding 3-methylbutanol and 3-methylbutyl acetate are produced similarly in banana (145, 163). Similar transformations of valine and phenylalanine are also carried out by banana slices (145). 

Buckner Discovered alcoholic fermentation in cell-free yeeist extract. 

Modified fermentation on the basis of worts with reduced extract values with strongly depressed or without any alcohol fermentation. 

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. 

Nogueira, A., Santos, L. D., Paganini, C., and Wosiacki, G. (2005). Evaluation of alcoholic fermentation of aqueous extract of the apple pomace. Semina Ciencias Agrarias, Londrina 26,179-193. 

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