Dedication to Professor Dr. Hermann Sahm on the occasion of his 65th birthday

Abstract

To mark the occasion of the 65th birthday of Prof. Dr. Hermann Sahm, we present in this issue of Applied Microbiology and Biotechnology a series of scientific articles which are dedicated to him. The senior authors of all these articles are current or previous members of the Institute of Biotechnology 1 (IBT1) at the Research Center Julich, and all authors understand their work as a dedication and a celebration of his anniversary on September 5. This is also true for a review article by Georg Sprenger, written in honour of Hermann Sahm, but unfortunately and inadvertently published already in a previous issue of this journal (Appl Microbiol Biotechnol 75:739–749). We would like to shortly introduce the reader to the scientific career and to the merrits of Hermann Sahm. After studying microbiology and biochemistry at the universities in Gottingen and Tubingen, Hermann Sahm did his PhD thesis on the formation of tryptophan by Escherichia coli K-12 in Hans Zahner’s Institute of Microbiology at the University of Tubingen. After his PhD in 1970, he joined Fritz Wagner’s lab at the Gesellschaft fur Biotechnologische Forschung (GBF) in Braunschweig, first as a postdoctoral fellow and later as an independent group leader. In this period, Hermann Sahm isolated and characterized Candida boidinii, a methylotrophic yeast, nowadays representing an excellent platform for the biotechnological production of heterologous proteins. The knowledge on the enzymes involved in methanol and ethanol oxidation in C. boidinii and several other organisms (including formate dehydrogenase, used today for reductive biotransformations) and on the physiology of methanol-utilizing yeasts and bacteria is the merrit of Hermann Sahm’s work at his time in Braunschweig. In 1976, Hermann Sahm obtained the “Habilitation” in Microbiology at the Technical University of Braunschweig, and in 1977, he became full professor at the University of Dusseldorf and simultaneously the first director of the newly founded Institute of Biotechnology at the Research Center Julich. After initial studies on the biology of anaerobic bacteria employed in wastewater treatment, his main fields of interest in the last three decades were the physiology, enzymology and molecular biology of biotechnological amino acid, vitamin and ethanol production with a variety of different microorganisms and, based on the knowledge obtained, the improvement and optimization of the production strains by metabolic engineering. Many bacterial and fungal enzymes and pathways important for metabolite production have been identified and extensively characterized in Sahm’s institute in Julich. Outstanding examples are the discovery of a split pathway for L-lysine biosynthesis in Corynebacterium glutamicum, the first identification of a bacterial amino acid exporter, the L-lysine exporter LysE, or the discovery of the first enzyme of a novel pathway of isoprenoid biosynthesis, 1-deoxy-D-xylulose 5-phosphate synthase. Aside from classical enzymological, physiological and genetic tools, Hermann Sahm and his coworkers were among the first to apply H-, C-, Pand N-NMR to determine quantitatively in vivo metabolic fluxes and to apply DNA microarray technology for global expression profiling of industrially important microorganisms. These approaches tremendously increased our knowledge on bacterial physiology and on the molecular mechanisms behind and stimulated further research directed to a systemic understanding of what really happens inside a (bacterial) cell. In all cases, however, Hermann Sahm looked for the application of the knowledge gained, very often in fruitful Appl Microbiol Biotechnol (2007) 76:483–484 DOI 10.1007/s00253-007-1110-x