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mentioned the various industries which aim at food preservation, as 

 well as those devoted to the preservation of wood. In addition, I 

 should remark that the industrial production of different types of 

 germicides has nowadays assumed considerable proportions. 



Until now I have merely stressed the necessity for the industrialist 

 to be quite vigilant in order to prevent 'illegal' chemistry in his factory. 

 However, the remarkable chemical achievements of micro-organisms 

 have quite naturally already led to the attempt to domesticate special 

 types in order to employ them for the bulk production of certain desir- 

 able products. 



Many obstacles had to be overcome in order to safeguard the do- 

 mestic microbes against the competitive actions of their wild con- 

 freres, but considerable success in this has gradually been achieved. 



The industrial production of ethyl alcohol by the fermentation of 

 sugars is, of course, the oldest example. Although nowadays there is 

 severe competition from synthetic processes, more than half of the 

 187,500,000 gallons produced in the U.S.A. in 1949 was obtained by 

 fermentation. With lactic acid the situation is even more favourable, 

 in so far as the industrial production of this compound is still complete- 

 ly based on the fermentation process, and the same holds for a minor 

 product like butyric acid. 



Apart from these classical fermentations which have developed 

 from a more or less empirical start, other dissimilatory processes have 

 been successfully applied in more recent times for the bulk production 

 of certain valuable organic compounds. We need only mention the 

 industrial production of n-butyl alcohol and acetone by fermentation 

 of corn mash or molasses, and the production of citric acid from the 

 latter source. Both industries have attained considerable dimensions, 

 the annual production in the U.S. alone amounting to about 70,000 

 tons of butyl alcohol, and to 15,000 tons of citric acid. Another fer- 

 mentation process which has found practical application in Holland, 

 albeit on a small scale only, is the production of 2,3-butanediol. 



From the examples given earlier it will be clear that there are still 

 many other microbial dissimilatory processes which could be con- 

 sidered for industrial application, and which from time to time have 

 received attention in this respect. I can refer to the production of kojic 

 acid and itaconic acid by moulds and to the recent suggestion made 

 by your compatriot Butlin to apply the dissimilation process of the 



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