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of cultures employed in these industrial fermentations may well have 

 originated from one bacterial cell whose dimensions, in comparison 

 with those of the earlier mentioned yeast cell, are very small indeed. 

 If we further realize that in a relatively short time that single, minute 

 cell has given rise to the construction of many imposing factories in 

 various parts of the world, then it is unavoidable not to be impressed 

 by the enormous powers that reside in even the smallest living entities. 

 Then, too, we cannot escape the notion that, in view of the thousands 

 of microbes that so far have only superficially been investigated, and 

 of the unknown numbers of microbes that occur on earth but have 

 never yet been observed by man, a rational exploration and exploita- 

 tion of the powers of the microbial world may still bring many benefi- 

 cial results to mankind. 



This possibility is strikingly illustrated by some procedures worked 

 out in Germany during the war emergency. I refer to the microbiolog- 

 ical production of fat and protein. It had long been known that under 

 certain conditions various micro-organisms accumulate fats and oils 

 as intracellular reserve products. Encouraged by the great demand for 

 fat during the war, Lindner made a careful study of this phenomenon, 

 hoping thereby to accomplish a technically feasible procedure for the 

 conversion of carbohydrates into fats. In a sample of some material 

 collected from the sap flow of a birch tree and which his pupil Schret- 

 tenfeger had sent Lindner from the Eastern front, the latter discov- 

 ered an organism, Endomyces vernalis, that appeared eminently suitable 

 for such a fat synthesis. It was found possible to obtain good yields of 

 this organism with a fat content of 60 per cent, calculated on a dry- 

 weight basis, by growing it in sugar media with a small amount of 

 ammonium sulphate as nitrogen source. 



A comparable situation is encountered in the microbiological pro- 

 tein synthesis, also evolved in the Tnstitut fur Garungsgewerbe' in 

 Berlin. Starting from the consideration that, after elimination of the 

 bitter ingredients introduced by the hops, the brewery yeast repre- 

 sents an eminently suitable, protein-rich fodder, Lindner further 

 investigated the possibility of manufacturing a protein-rich yeast pro- 

 duct from readily available inorganic nitrogen sources, primarily am- 

 monium sulphate, reasoning that, at least during periods of severe 

 food scarcity, such a process might be economically important. As a 

 result of this investigation many factories in Germany actually pro- 



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