BIOGRAPHICAL MEMORANDA 



Kluyver's early investigation of the assimilation of disaccharides in 

 which it had been found that maltose could act as a satisfactory nu- 

 trient by virtue of the impurities it contained. But in that case the 

 predicament was a fundamentally different one because the fact that 

 purified maltose failed to induce growth could only mean that other 

 substances were responsible for the effects and it was not necessary to 

 identify them. In the present case the question was whether or not 

 anaerobiosis could inhibit the activity of hydrolases of particular 

 yeasts. Hence a negative result would have invalidated the inter- 

 pretation proposed by Kluyver and Custers, and the withholding of 

 pertinent experimental results would not have been sound scientific 

 strategy. Therefore it seems more reasonable to conclude that the 

 experiments were not performed. 



This same publication also contains some remarks indicative of 

 Kluyver's dissident attitude towards the concept of a 'direct' oxidation 

 of disaccharides. It was claimed, for example, that 'it is also quite 

 difficult to conceive that a disaccharide will undergo oxidation with- 

 out preceding hydrolysis. . . . Such a "direct" oxidation ... is further 

 quite incompatible with the unitarian theory of respiration and fer- 

 mentation' (p. 122). Again the implication seems to be that the 'uni- 

 tarian theory' must be considered as the most satisfactory guide in for- 

 mulating interpretations of biochemical phenomena. But in science a 

 theory, no matter how attractive, must yield to facts, and in later years 

 Kluyver had to admit the existence of such direct oxidations. In fact, 

 with De Ley and Rijven [1951] he extended the earlier observations 

 of Stodola and Lockwood on the oxidation of maltose and lactose to 

 malto- and lactobionic acids. In a way this was not too revolutionary 

 a discovery, for these oxidations are carried out by members of the 

 Pseudomonas group with a strictly oxidative metabolism, and it was al- 

 ready known that at least some species of this group also oxidize 

 glucose directly to gluconic acid. In this, as in other respects, these 

 microbes resemble the acetic acid bacteria, and for the latter an ini- 

 tial non-oxidative conversion of sugar to triose had never been as- 

 sumed. 



Strict adherence to the unitary theory of fermentation and oxida- 

 tion had to be abandoned, however, when soon afterwards it was 

 established that the typically fermentative metabolism of some bac- 

 teria also proceeds via a primary oxidation of hexose sugars. By the 



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