Sulfur Metabolism of Microorganisms

Production of 5-methylthioribose was demonstrated for the first time in bacteria, and it was shown that Escherichia coli B formed this compound inside the cells, then lost it to the medium. Effects of inoculum size, sulfate concentration, time of sulfate addition and levels of other exogenous nutrients were studied. Some other microorganisms also formed methylthioribose although not all did so. Study of sulfur metabolism in an anaerobic bacterium was initiated with Clostridium pasteurianum. Conditions of culture were improved to facilitate growth from small inocula and incubation with small additions of sulfate. Sulfate-dependent growth in defined medium was achieved. No maintenance requirement for exogenous sulfur sources could be detected. E. coli forms many small sulfur metabolites from sulfate in glucose-salts medium. A similarly broad range of such compounds was demonstrated in other microorganisms. Structure work was initiated on two of these, one a methylthiocarbohydrate and the other a methylthiocarboxylic acid. (Modified author abstract) Includes reprint 'Biological Production of 5-Methylthioribose' Canadian Jnl. of Microbiology, v19 n11 p1347-1354 1973.