Microbial Oxidation of Sulfides

Abstract

This paper reviews the current state of biooxidation of metal sulfide minerals. The review summarizes microbiological and chemical basics regarding this process, where special attention has been paid to biochemical processes resulting in biooxidation of sulfide and ferrous ions. Basically, there are two main methods of microbial metal sulfide oxidation, thiosulfate and polysulfide pathways. Despite the bacterial participation in mineral oxidation, both pathways are considered to be indirect chemical processes. The function of micro­organisms is primary in regeneration of oxidizing agents or generating H⁺ ions. The biochemical pathways of these processes are not yet clearly identified but relevant findings based on biochemical stu­dies of the model organisms Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans have been made. This review also considers the role of extracellular polymeric substances in biooxidation of metal sulfides.