A SERENDIPIC LEGACY - ESMARCH,ERWIN ISOLATION OF THE FIRST PHOTOSYNTHETIC BACTERIUM IN PURE CULTURE

During the 1880's, Erwin von Esmarch was a junior associate ('Assisten t') of Robert Koch studying bacteria of medical significance. In 1887, he isolated the first example of spiral-shaped bacteria in pure cultu re, from the dry residue of a dead mouse that he had suspended sometim e earlier in Berlin tap-water. Under certain conditions, colonies of t he organism were the color of red wine, and this led Esmarch to name t he bacterium Spirillum rubrum. Twenty years later, Hans Molisch demons trated that S. rubrum, an apparent heterotroph, was in fact a non-oxyg enic purple photosynthetic bacterium, and it was renamed Rhodospirillu m rubrum. Esmarch was a careful investigator and his classic paper of 1887 details the serendipitous isolation and general characteristics o f the first pure culture of an anoxyphototroph, which later played a p rominent role as an experimental system for study of basic aspects of bacterial photosynthesis. This report includes an English translation of his original paper (in German), a commentary on the historical sign ificance of 'Esmarch's spirillum', and a summary of Esmarch's career.