MICROBIAL METABOLISM AND ITS INDUSTRIAL IMPLICATION'S 



Survey of fermentations leading to the formation of 2,3-butanediol 

 Aerobacter aerogenes (chiefly meso, besides dextro) 

 Aerobacillus polymyxa (laevo) 



C 6 H 12 6 -» CH 3 -CHOHCHOHCH 3 + 2 C0 2 +H 2 



Serratia marcescens (chiefly meso, besides dextro) 



C 6 H 12 6 -> CH 3 CHOH-CHOHCH 3 +HCOOH+C0 2 



Bacillus subtilis Ford-strain 



[= Bacillus licheniformis (Weigmann) Gibson] (meso and laevo in equal quantities) 

 3 C 6 H 12 6 -> 2CH 3 -CHOHCHOHCH 3 + 



+ 2CH 2 OH • CHOH • CHoOH +4C0 2 



As is shown in Table X the configuration of the diol formed depends 

 on the type of bacteria used in the fermentation. In Canada the use 

 as 'antifreeze' of the laevo-compound, as formed practically exclusive- 

 ly in the fermentation of sugar or starch by Aerobacillus polymyxa, has 

 been seriously considered. In contrast, the meso-form of the diol has 

 been shown to be completely unsuitable for the purpose. 



In such special cases, therefore, even the bulk production of micro- 

 bial dissimilatory products, may be able to compete successfully with 

 synthetic processes. 



New vistas for industrial microbiology are revealed when we realize 

 that the foregoing discussion has been confined to the dissimilatory 

 processes, but that the true greatness of microbial metabolism mani- 

 fests itself in the assimilatory processes, i.e., in those processes which 

 are the basis of the proliferation of the micro-organism. Evidently, 

 part of the food components are converted into cell constituents in 

 their almost endless diversity. Although as a rule assimilation general- 

 ly ranks far below dissimilation from a quantitative point of view, 

 compensation may often be found in the qualitative value of many 

 assimilation products for mankind. It seems difficult to overrate the 

 remarkableness of these chemical reactions which together constitute 

 assimilation, and the word super-chemistry may well be coined for 

 them. 



Although the riddles of this 'super-chemistry' are still far from being 

 solved, great progress has been made during the last decade. 



The main barrier to a better understanding of assimilatory chem- 



461 



