Inorganic Sulfur Oxidation by Aureobasidium pullulans.

Aureobasidium pullulans (de Bary) Arnaud isolated from the phylloplane of sycamore exposed to heavy atmospheric pollution oxidized S to S(2)O(3), S(4)O(6), and SO(4) in vitro. The intermediates S(2)O(3) and S(4)O(6) were also oxidized to SO(4). Cell-free extracts of A. pullulans also oxidized reduced forms of S, the oxidation increasing linearly with increasing protein concentration, showing that the process is enzymatic. The possible role of fungi in S oxidation in soils is discussed.