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National Resources Planning Board 



the removal of the cofTee "bean" from outer skins and 

 pulp and a possibly controlled fermentation of the 

 coffee bean to improve flavor and aroma. Likewise, 

 the removal of cocoa beans from pod and pulp and the 

 accompanying fermentation are being studied, as is 

 the "fermentation" of tea leaves. Important studies 

 on the staling of coffee have recently appeared. 



Fermented foods. — The biologist is essential to indus- 

 tries which manufacture fermented foods like sauer- 

 kraut, picldes, olives, fermented milks, vinegar, and 

 beverages such as beer, and wines. Bacteriologists 

 and biochemists have developed satisfactory methods 

 for the preparation of sauerkraut and have investigated 

 the bacterial flora and causes of spoilage. Similar 

 work on cucumber pickles and olives is occupying the 

 attention of biologists in these industries. Although 

 the manufacture of vinegar by fermentation has been 

 carried on for centuries, methods of production have 

 recently been so greatly improved as to be almost 

 completely revolutionized. 



In fermentation industries like brewing and wine 

 making, the yeasts used are studied for food require- 

 ments, methods of propagation, maintenance of desired 

 characteristics, and possible improvement of their 

 activity. The aging of the products, maintenance or 

 improvement of their quality, and prevention of spoil- 

 age also are being investigated. 



A recent development of great importance to the food 

 industry is the development of a yeast containing 10 to 

 20 times as much vitamin Bi as that of ordinary beer or 

 baker's yeast. The development of special strains of 

 yeast and methods of growing for the production of 

 ergosterol and riboflavin are examples of research in this 

 field. A special yeast high in invertase activity has also 

 been recently developed. 



Fermentation Industries 



It has been estimated that the present annual produc- 

 tion of fermented products and chemicals produced by 

 fermentation is about as follows: 



Malt liquors, 1,669 million gallons. 



Wines and spirits, 145 million gallons. 



Industrial alcohol, 152 million gallons. 



Acetone (including synthetic) and butyl alcohol, 150 



million pounds. 

 Lactic acid, 1,292,000 pounds edible and 5-7 million 



pounds, technical. 

 Citric acid, 15 million pounds. 

 Gluconic acid, 500,000 pounds. 

 Sorbose, 100,000 pounds. 



New organisms. — In the highly competitive fermenta- 

 tion industries there is a constant pressure for improve- 

 ment of the processes, as witness the numerous patents. 

 While it is not possible to patent an existing micro- 

 organism as such, it is considered a point of novelty and 



a patentable feature if one has developed an organism 

 having characteristics commercially significant. If a 

 company is not to be the prey of any inventor who 

 comes to offer a new organism, it should itself ex- 

 plore the possibilities of isolation and testing of 

 new organisms. Some large companies recognize this 

 and have in their employ trained bacteriologists or 

 mycologists. 



Changing economic conditions may so affect the avail- 

 ability or price of the raw carbohydrate for the fermen- 

 tation as to cause a change in desirability of an organism 

 for a given fermentation. For example, in the early 

 years of butyl fermentation, the Weizmann organism 

 held the field because of its superiority in the production 

 of butyl alcohol and acetone from com. Some 10 years 

 ago molasses displaced com, and immediately butyl 

 organisms of a new type were in demand. Their dis- 

 covery was an assignment for the microbiologist, and to 

 his credit may it be said that by deliberate selection 

 from many new isolations of. butyl bacteria he found new 

 species and particular strains far superior to the original 

 commercial butyl types. A spectacular current devel- 

 opment is a new technique for the controlled adaptation 

 of micro-organisms. 



Nutritional requirements. — It is obvious that to grow 

 bacteria and yeast one must supply the proper food. 

 Unfortunately all the factors involved in the growing 

 process are not known even by the best informed. The 

 gross energy-yielding nutrients are known but the re- 

 quirements for optimum functioning are but imperfectly 

 understood. It is becoming increasingly evident that 

 bacteria and even higher plants require vitamins just as 

 much as do higher animals. In nature micro-organisms 

 may obtain these substances from one another or from 

 other plant and animal materials. In industrial opera- 

 tions the micro-organism is shut off from associated 

 organisms and must depend upon the food supply offered 

 or upon its own synthetic powers. By and large, shot- 

 gun methods of supplying these feeds are employed, 

 such as use of extracts of natural materials in the fermen- 

 tation mashes. When it is not known what growth 

 factors are required, it is impossible to determine except 

 by trial and error experimentation whether or not the 

 factor needed is present in the extract. In microbiology 

 the necessity for growth factors has long been appreci- 

 ated. Because of recent developments in animal nutri- 

 tion, advance Ln the knowledge of the nutrition of 

 micro-organisms has been accelerated. 



Physical factors. — Consideration must be given also 

 to such factors as optimum temperature, hydrogen- 

 ion concentration, and oxidation-reduction potential. 

 Means of control of these factors are well known to the 

 biologist but their need is frequently not recognized by 

 plant operators. 



