96 Perspectives in Microbiology 



cumulated on the earth to an incredible degree. If one 

 assays the participation of fungi in the vast and inexorable 

 decay process which pervades nature, of necessity one be- 

 comes convinced that, along with bacteria and actino- 

 mycetes, the fungi play a prominent role. Seeking details 

 of the metabolic processes and pathways whereby the mul- 

 tifarious organic compounds of nature are catabolically 

 attacked by various individual fungi, one does, however 

 rather quickly perceive that the available information deals 

 overwhelmingly with one class of compounds, that is, car- 

 bohydrates. Compared to the extensive variety of catabolic 

 mechanisms known in the diverse bacteria utilizing mani- 

 fold compounds, those known in the fungi can hardly be 

 considered numerous. Undoubtedly, the obvious preoccu- 

 pation with carbohydrate metabolism of fungi is ascrib- 

 able, in large degree, to the industrial significance of 

 certain carboxylic acids produced from carbohydrates. The 

 disparity between numbers of bacterial and of fungal 

 catabolic pathways points up vast gaps in our knowledge 

 of mold metabolic types, and at once stakes out enormous 

 areas awaiting what surely will be fruitful exploration. 



And the approach here may be quite direct, for the 

 basic requirement is simply an array of pure cultures of 

 fungi, each capable of utilizing a single compound as the 

 sole source of carbon or nitrogen or both. The important 

 thing here is the great number of diverse compounds avail- 

 able for this purpose. When this potential metabolic in- 

 formation becomes translated into real information, the 

 present status of mold metabolism will, in retrospect, ap- 

 pear modest indeed. 



Testing of existing stock cultures will not, I should 

 judge, be enough to procure the necessary scope of sub- 

 strate attack; for, notwithstanding the great number of 

 morphologically different fungi available in pure culture 

 today, one might suspect that the conditions of their origi- 

 nal isolation from nature undoubtedly have resulted in 

 more homogeneity than heterogeneity of metabolic types. 



