Isolation and characterization of a new acidophilic Thiobacillus species (T. albertis)

Abstract

An acidophilic, rod-shaped, S-oxidizing bacterium was isolated from extremely acidic soil adjacent to a S stockpile. This isolate grows only autotrophically by oxidizing So and reduced inorganic S compounds S2O32- and S4O62-), placing it in the genus Thiobacillus. Aerobic growth was observed over a pH range of 2.0-4.5 with optimum growth at 3.5-4.0. Analysis of its DNA revealed a mol% G + C content of 61.5. Ultrastructural studies showed that the isolate possessed a tuft of polar flagella. A glycocalyx was observed only after the antiserum stabilization procedure, which showed it extending outwards from the outer membrane of the bacterial cell envelope. Cleavage planes of this cell showed a typical gram-negative cell wall. The cytoplasm contained 2 types of inclusion bodies, carboxysomes and a single large membrane-bound S granule. This isolate had morphological and physiological characteristics which were not totally comparable with other known acidiophilic thiobacilli, demonstrating this bacterium to be a new Thiobacillus sp. named T. albertis.