Fermentation simultaneous

Primitive people very likely encountered vinegar-like Hquids in hoUows in rocks or downed timber into which berries or fmit had fallen. Wild yeasts and bacteria would convert the natural sugars to alcohol and acetic acid. Later, when eady peoples had learned to make wines and beers, they certainly would have found that these Hquids, unprotected from air, would turn to vinegar. One can postulate that such eady vinegars were frequendy sweet, because the fmit sugars would have been acted on simultaneously by both bacteria and yeast. Only since the middle 1800s has it been known that yeast and bacteria are the cause of fermentation and vinegar formation. 

Yeast (qv) metabolize maltose and glucose sugars via the Embden-Meyerhof pathway to pymvate, and via acetaldehyde to ethanol. AH distiUers yeast strains can be expected to produce 6% (v/v) ethanol from a mash containing 11% (w/v) starch. Ethanol concentration up to 18% can be tolerated by some yeasts. Secondary products (congeners) arise during fermentation and are retained in the distiUation of whiskey. These include aldehydes, esters, and higher alcohols (fusel oHs). NaturaHy occurring lactic acid bacteria may simultaneously ferment within the mash and contribute to the whiskey flavor profile. 

Starting from an inoeulum, at t = 0, and an initial quantity of limiting substrate at t = 0, the biomass will grow after a short lag phase and will eonsume substrate. The growth rate slows as the substrate eoneentration deereases, and beeomes zero when all the substrate has been eonsumed. Simultaneously, the biomass eoneentration initially inereases slowly, then faster until it levels off when the substrate beeomes depleted. Figure 11-21 shows a sketeh of a bateh fermenter. 

The (ZZ-ephedrine was resolved into its components by the use of d-and Z-mandelic acids. In 1921 Neuberg and Hirsch showed that benz-aldehyde was reduced by yeast, fermenting in suerose or glueose solution to benzyl aleohol and a phenylpropanolone, which proved to be Z-Ph. CHOH. CO. CH3. This ean be simultaneously, or consecutively, eondensed with methylamine and then eonverted to Z-ephedrine by reduction, e.g., with aluminium amalgam in moist ether, or by hydrogen in presenee of platinic oxide as catalyst (Knoll, Hildebrant and Klavehn ). 

Chloramphenicol may be prepared by fermentation or by chemical synthesis. The fermentation route to chloramphenicol is described in U.S. Patents 2,4B3,B71 and 2,4B3,B92. To quote from U.S. Patent 2,4B3,B92 The cultivation of Streptomyces venezuelae may be carried out in a number of different ways. For example, the microorganism may be cultivated under aerobic conditions on the surface of the medium, or it may be cultivated beneath the surface of the medium, i.e., in the submerged condition, if oxygen is simultaneously supplied. 

The bacterial culture converts a portion of the supplied nutrient into vegetative cells, spores, crystalline protein toxin, soluble toxins, exoenzymes, and metabolic excretion products by the time of complete sporulation of the population. Although synchronous growth is not necessary, nearly simultaneous sporulation of the entire population is desired in order to obtain a uniform product. Depending on the manner of recovery of active material for the product, it will contain the insolubles including bacterial spores, crystals, cellular debris, and residual medium ingredients plus any soluble materials which may be carried with the fluid constituents. Diluents, vehicles, stickers, and chemical protectants, as the individual formulation procedure may dictate, are then added to the harvested fermentation products. The materials are used experimentally and commercially as dusts, wettable powders, and sprayable liquid formulations. Thus, a... 

Effect of Pretreatment on Lactic Acid Fermentation of Bean Curd Refuse with Simultaneous Saccharification... 

Dry bean curd refuse was used as the substrate in the lactic acid fermentation with simultaneous saccharification (SSF). The dry bean curd refuse was preliminarily sieved under a mesh size of 250 II m. It contained 12.3% water, 4.0% ash, 0.8% lipid, 29.3% protein, 53.6% carbohydrate, respectively, in weight basis. The cellulase derived from Aspergilltis niger with an enzymatic activity of 25,000 units/g (Tokyo Kasei Industry Inc.) was employed as the saccharification enzyme. 

For lactic acid fermentation of bean curd refuse with simultaneous saccharification, it is found that the pretreatment of the substrate using 0.1 or 0.2 mol/l HCl aqueous solution with heating at niTi for 30 min efficiently solubilized the raw material and significantly enhanced the enzymatic saccharification followed by the lactic acid fermentation. The amount of initial load of bean curd refiise in dried state could be increased up to 75 g/1 in a batch fermentation, and the finally attained lactic acid yield and its concentration were as high as 87.0% and 45.8 g/1, respectively. 

Gas logging, the adherence of small bubbles to particles, causing them to rise to the surface in the reactor and form an inefficient packed bed with poor mass transfer properties, can be a problem in various fermentations and in wastewater treatment. A double entry fluidized bed reactor has been developed with simultaneous top (inverse) and bottom (conventional) inlets to overcome this problem (Gilson and Thomas, 1993). 

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