Mash, commercial production

Finally, it should be noted that commercial production of ethanol by continuous fermentation of grain mash has reportedly been achieved at Archer-Daniels-Midland Company and that National Distillers researchers have also developed such a process. Although continuous fermentation, per se, is not new there is some skepticism concerning the degree to which this represents a real technical and economic advance. ... 

Fermentative Manufacture. Throughout the years, riboflavin yields obtained by fermentation have been improved to the point of commercial feasibiUty. Most of the riboflavin thus produced is consumed in the form of cmde concentrates for the enrichment of animal feeds. Riboflavin was first produced by fermentation in 1940 from the residue of butanol—acetone fermentation. Several methods were developed for large-scale production (41). A suitable carbohydrate-containing mash is prepared and sterilised, and the pH adjusted to 6—7. The mash is buffered with calcium carbonate, inoculated with Clostridium acetohutylicum and incubated at 37—40°C for 2—3 d. The yield is ca 70 mg riboflavin/L (42) (see Fermentation). 

Castor beans are grown commercially for castor oil. Castor oil has sought-after industrial and automotive applications. The annual production of castor bean waste mash exceeds 1 million tons (Doan, 2004). Castor bean cake is also sold as fertihzer. Ricin is easy to extract from castor bean meal. 

Commercial Yeast.—The application of the principles just developed is well illustrated in the manufacture of yeast for general use. The same niceties observed in this process must also be followed in the production of so-called starters for the fermentation of whiskey mashes or of wine must. Figure 6 is the flow sheet of such a process. The exact proportions of the various grains used are naturally varied according to the secret formula of the manufacturer. 

There are two major areas of commercial application of acetic add today food-grade vinegar, which is largely the product of bacterial oxidative conversion of diluted purified alcohol or alcoholic mashes from various fruits and grains, and chemically synthesized industrial acetic acid, 62 % of which is produced by carbonylation of methanol and the rest by oxidation of -butane. Chemically synthesized acetic acid is a commodity chemical that has become a major feedstock for the United States and worldwide chemical industry. O Figure 1.5 displays the major chemicals derived from acetic acid and their commercial applications. 

The tendency to variation in B. polymyxa which is brought out by the above studies makes it unsuited to commercial use. In addition it produces considerable ethyl alcohol, the fermented mash is difficult to filter and process, and the total concentration of products is less than in the aerogenes fermentation. Experimenters have thus come to the conclusion that if grain is to be used, it would be preferable to acid-hydrolyze the starch to sugar and ferment with aerogenes. This is further supported by the work of Katznelson (66,67), who showed B. polymyxa to be quite sensitive to bacteriophage. 

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