Taxonomic study of coryneform bacteria with special reference to a chemotaxonomic approach

―In memory of Prof. Kazuo Komagata―

Abstract

The great contribution of the late Prof. Kazuo Komagata to the taxonomy of coryneform bacteria is introduced. Coryneform bacteria have been defined as irregular nonsporing Gram-positive rods. Coryneform bacteria are widely distributed in, for example, animal pathogens, plant pathogens and soil habitat, and their taxonomy was in confusion. In 1958, glutamic acid-producing bacteria were found and developed for industrial amino acid production. The taxonomic position attracted attention because of a patent dispute. Prof. Komagata collected a wide variety of coryneform bacteria and studied the taxonomy using a polyphasic approach including newly introduced chemotaxonomy as well as morphological and physiological/biochemical tests and successfully classified them at the genus level. Since then, the chemotaxonomic approach, involving for example the peptidoglycan structure, menaquinone, and the cell wall acyl type, has played an important role in the progress of the taxonomy of coryneform bacteria. More recently, phylogenetic taxonomy based on 16S rRNA sequences has been used to construct the higher taxa and support the usefulness of chemotaxonomy as regards phenotypic characteristics. Harmonization of this work with that of microbiologists by sharing microbial resources to enrich the information obtained using culture collection is important for the future progress of microbial taxonomy.