Jozef De Ley

Born in 1924 in Ghent, Jozef De Ley studied chemistry at Ghent University. He obtained the PhD degree in 1949 and the Aggregate for Higher Education in 1958, with a fundamental contribution on novel aspects of the oxidative metabolism of carbohydrates by microorganisms. Professor De Ley performed research at the laboratory of A.I. Virtanen (Helsinki, Finland), the Microbiology Laboratory (A.J. Kluyver) in Delft, the Netherlands, and the Department of Bacteriology (M. Doudoroff) at the University of California in Berkeley, U.S.A.

He was the founder of the Laboratory of Microbiology at the Faculty of Sciences of Ghent University, where research initially focused mainly on comparative aspects of bacterial metabolism. This led to the discovery of new enzymes, new metabolites and pathways. In 1961, a half-year sabbatical visit to the Department of Microbiology at the University of Illinois in Urbana, U.S.A. stimulated him and fellow staff members in Ghent to start investigations on the genomic relationships of various groups of Gram negative bacteria. This was carried out with the aid of molecular techniques such as DNA:DNA hybridisations and mol% G+C determinations of genomic DNA. The optimisation and standardisation of the DNA:rRNA hybridisation technique, emphasising Tm(e) as the relevant taxonomic parameter, were the start of a comprehensive phylogenetic study of the Proteobacteria, resulting in numerous publications and a growing scientific recognition. He introduced the numerical treatment of microbiological data in Gent, and advocated a polyphasic approach in bacterial taxonomy.

De Ley was visiting professor at many foreign universities and was frequently invited to speak at international congresses and symposia. He was also member of several taxonomic subcommittees of the ICSB.

De Ley and his team made numerous contributions to the international literature on bacterial biochemistry and taxonomy. The genus Deleya and the new species Sulfurospirillum deleyianum were named after him.

In the 1984 edition of the taxonomic 'bible' (Bergey's Manual of Systematic Bacteriology), De Ley was co-author of the chapters on the genera Acetobacter, Agrobacterium, Alcaligenes, Frateuria, Gluconobacter and Zymomonas. He was also author or co-author of a number of chapters in the second edition of a four-volume standard work named 'The Prokaryotes'.

De Ley received the Bergey Award in 1985 and the C.B. van Niel International Prize 1990 - 1994 for his numerous contributions to bacterial systematics. He retired in 1989.

Jozef De Ley was highly energetic and determined. He was a hard-working, conscientious scientist and teacher, who stimulated many Belgian and foreign PhD students. He devoted the greater part of his lifetime to microbiology. The microbiological community will remember Prof. Jozef De Ley as one of the pioneers of modern microbial taxonomy.