Phosphite oxidation by sulphate reduction

摘要

Biological phosphorus occurs almost exclusively as phosphate in the redox state of + Ⅴ, although a few phospho-nic (+ Ⅲ) and phosphinic (+Ⅰ) acids are found as secondary metabolites or as constituents of phosphonolipids. Here we show that a culture of a lithoautotrophic bacterium purified from marine sediments in Venice can grow by anaerobic oxidation of phosphite (+ Ⅲ) to phosphate (+ Ⅴ) while simultaneously reducing sulphate to hydrogen sulphide. To our knowledge, this is the first description of a redox reaction involving phosphorus in microbial energy metabolism, an activity that might have operated on the early Earth and which could represent an ancient evolutionary trait.