MANUFACTURE OF INDUSTRIAL ALCOHOL FROM MOLASSES 335 



countered the grain miller generally fortifies the naturally occurring 

 amylases with either wheat or barley malt (germinated wheat or 

 barley). Other substances are often added to the dough. Although 

 there is usually sufficient calcium and phosphorus in the dough to 

 satisfy the nutritional requirements of yeast, they are usually com- 

 ponent parts of so-called bread improvers or dough conditioners. 

 Although the breakdown of wheat proteins by the proteolytic enzymes 

 normally present in wheat or in the diastatic preparations added to 

 the dough usually supplies the nitrogenous compounds, additions of 

 slight amounts of ammonium compounds cause rapid increase in the 

 production of gas. Propionates and diacetates (generally the so- 

 dium salts) may also be added to flour to inhibit the development of 

 molds in the finished bread. They have the added value of retarding 

 development of "rope" (an undesirable condition caused by certain 

 strains of Bacillus mesentericus) in bread. 



After the starch has been hydrolyzed to maltose, this dissacharide 

 is acted upon by the maltase of yeast which converts it to glucose. 

 The zymase complex attacks the hexose, carrying out the alcoholic 

 fermentation with formation of carbon dioxide and alcohol. The 

 former causes the dough to rise, the latter being driven off, for the 

 most part, during the baking. Flavors are imparted to bread, in 

 part, by minute quantities of esters which are also formed in the 

 fermentation. The proteolytic enzymes of yeast are said to cause 

 desirable changes in the wheat gluten. 



Industrial Alcohol Produced by Fermentation. Large quantities 

 of alcohol required for industrial purposes are produced by fermenta- 

 tion with yeasts. Raw materials may consist of any fermentable 

 saccharine material or carbohydrate which can be hydrolyzed to 

 fermentable sugars. 



Ordinarily, the organisms used are strains of Saccharomyces 

 cerevisiae, capable of tolerating high alcohol concentrations. How- 

 ever, strains of Schizosaccharomyces Pomhe have also been used. 

 The starter is prepared by growing and transferring the yeasts in 

 successively larger volumes of cultures and mashes until the volume 

 is large enough for pitching the main mash. 



The Manufacture of Industrial Alcohol from Molasses. In the 

 United States and Canada, blackstrap molasses, a by-product of 

 cane sugar refineries, is the most common raw material. It contains 

 sugar and, generally, most of the nutrients required for the growth 

 of yeast cells which carry out the fermentation. 



The mash is prepared so that the sugar concentration is between 

 10 and 15 per cent. Higher concentrations of sugar may have a 



