Utilisation of aromatic organosulfur compounds as sulfur sources by Lipomyces starkeyi CBS 1807

Aromatic organosulfur compounds that contain aryl carbon-sulfur bonds are rare in nature but occur frequently in industrial processes and products. The utilisation of aryl sulfur compounds as a sulfur source has not been described previously among the budding yeasts (phylum Ascomycota, sub-phylum Saccharomycotina). A total of 31 strains representing 30 species and 28 genera of the budding yeasts were assayed for utilisation of benzene sulfonate as source of sulfur. Lipomyces starkeyi CBS 1807 was the only strain in this screen that was able to utilise benzene sulfonate as a sulfur source. Further study of L. starkeyi demonstrated that it could also utilise methyl phenyl sulfoxide, 1-naphthalene sulfonate, 2-naphthalene sulfonate, 1-anthraquinone sulfonate and 2-anthraquinone sulfonate as sulfur sources but not diphenylsulfone. This study represents the first reported case of the utilisation of sulfonated naphthalenes and anthraquinones as sulfur sources by a fungus. However, it should be stressed that the remaining 30 strains in this study were not assayed for the utilisation of these additional aryl sulfur compounds as sulfur sources. The present study highlights the potential of L. starkeyi and related species as a source of novel enzyme activities with possible applications in chemical manufacturing, disposal of xenobiotics and bioremediation.