Factors affecting the growth of some fungi associated with sewage purification.

Abstract

Summary: Various aspects of the nutrition of four fungi which commonly inhabit percolating filters treating sewage have been studied. Sepedonium n.sp., a predominating fungus, required organic sources of nitrogen while Fusarium aqueductum, Geotrichum sp., and Trichosporon cutaneum were able to utilize ammonium salts; F. aqueductum was also able to utilize nitrate. Geotrichum sp. and F. aqueductum needed no external supply of vitamins, T. cutaneum required thiamine and Sepedonium sp. required thiamine and biotin for optimum growth. The pH range for optimum growth was narrow (pH 7 to 8·5) for Sepedonium sp. while the ranges for the other fungi were much wider (pH 3 or 4 to 9). Zn, Ca, Mn and probably Fe and Cu were required by Sepedonium sp., which was the only one of the four fungi inhibited by concentrations of Zn above the optimum in media partially deficient in other elements. Mn, Fe or Cu when added with Zn counteracted the inhibitory action, while Ca increased it.