Isolation and characterization of a new acidophilic <i>Thiobacillus</i> species (<i>T</i>. <i>albertis</i>)

Abstract

An acidophilic, rod-shaped, sulfur-oxidizing bacterium was isolated from extremely acidic soil adjacent to a sulfur stockpile at Fox Creek, Alta. This isolate was found to grow only autotrophically by oxidizing S° and reduced inorganic sulfur compounds (S 2 O 3 2− and S 4 O 6 2− ), placing it in the genus Thiobacillus. Aerobic growth was observed over a pH range of 2.0 to 4.5 with optimum growth at 3.5 to 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 two types of inclusion bodies, carboxysomes and a single large membrane-bound sulfur 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.