BIOGRAPHICAL MEMORANDA 



But it must also be remarked that it has subsequently been shown 

 that some yeasts can actually grow at the expense of disaccharides 

 only in the presence of air, whilst their development in the absence 

 of oxygen is restricted to media containing a fermentable mono- 

 saccharide. In fact, Kluyver and Custers [1940], during a reinves- 

 tigation of the differential behaviour of yeasts towards disaccharides 

 under aerobic and anaerobic conditions, established that Brettanomyces 

 anomalus, Candida parakrusei, T. dattila, and T. utilis can grow with 

 maltose as the sole carbohydrate only in the presence of air, and 

 that some other yeast species exhibit a similar pattern with respect 

 to sucrose and lactose. 



THE EMERGENCE OF A PROGRAMME 



Whatever importance we may attach to these studies on yeast physiol- 

 ogy and their application, it must be realized that they constituted 

 Kluyver's only contribution to microbiology, and practically the en- 

 tire extent of his microbiological experience up to the time of his 

 succession to Beijerinck's chair. Hence it is understandable, as already 

 remarked in the introduction, that in his inaugural address he could 

 only hint at some general lines of investigation, and these quite 

 vaguely outlined, that might be pursued in his institute. During the 

 first several months of his directorship he was occupied exclusively 

 with preparing a background of knowledge of the field that would at 

 least permit him to expound the fundamentals of microbiology in his 

 courses, and to guide in an intelligent manner the work of the students 

 who came to work under his direction. During this preparatory phase 

 he received much support from the two assistants he had inherited 

 from Beijerinck, L. E. den Dooren de Jong and H.J. L. Donker. In 

 later years he was wont to acknowledge the debt of gratitude he owed 

 them, especially the former, who had acquired a thorough training 

 under Kluyver's famous predecessor, and possessed a considerable and 

 integrated knowledge of the micro-organisms. Needless to say, Kluyver 

 was an apt pupil. 



The first impetus to the development of a more specific programme 

 was provided by the fortuitous isolation of an unusual vinegar bac- 

 terium. The isolation of vinegar bacteria from beer that had become 

 acid after exposure to the air was one of the early experiments by 



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