Biological sulphate reduction

Abstract

Sulphate is reduced to thiols by micro-organisms and plants and these are incorporated via amino acids into protein. Higher animals however do not utilize sulphate and get their sulphur thiol groups usually from amino acids. Some bacteria also use sulphate as an alternative to oxygen as a hydrogen acceptor. Biochemical evidence suggests that sulphate is first activated by adenosine triphosphate (ATP) before it is reduced. Two sulphur-containing nucleotides, adenosine-5′-phosphosulphate (APS) and adenosine-3′-phosphate 5′ phosphosulphate (PAPS) have been identified as carriers of sulphur in bacteria and in green plants during sulphate reduction. Enzymes associated with sulphate and sulphite reduction in bacteria and in green plants are described in this paper, and ecological and economic aspects of the dissimilation of sulphate by bacteria are also considered.