Sulphur oxidation by fungi

Abstract

Aspergillus niger oxidized elemental sulphur in vitro to form relatively large amounts of sulphate, initially producing thiosulphate, but not tetrathionate. Growth was inhibited by thiosulphate, but not by elemental sulphur, although both were oxidized to sulphate. Mucor flavus also oxidized elemental sulphur, but while it produced less sulphate than A. niger , it consistently formed both thiosulphate and tetrathionate. Substantial sulphur oxidation by Trichoderma harzianum occurred only when large amounts of sucrose were provided, but it was able to oxidize elemental sulphur in autoclaved soil and to use straw to support sulphur oxidation in vitro. The relevance of these findings to the oxidation of sulphur in soils by fungi is discussed.