Nutrition and growth of the nematophagous fungus Arthrobotrys oligospora

Abstract

The growth conditions and the nutritional requirements of Arthrobotrys oligospora, a nematophagous fungus, were investigated in liquid culture. The organism was incubated in a synthetic medium, at 30° C in a static culture. Time course of growth was adjusted to a 3° degree equation, even after 15 days of incubation. Optimal temperature and pH for mycelium production were observed at 25° C and pH 5.0, respectively. However, significant differences were not found among the biomass production at temperatures 25° C and 30° C or pH 5.0 and 6.0. Several carbon sources were used by the fungus, but the highest biomass production were attained with maltose and sucrose. Of the nitrogen sources tested, several proteins (tryptone, yeast extract, casein, peptone and casaminoacids) and inorganic sources (sodium nitrate and ammonium chloride) stimulated the highest biomass yield. Of the several vitamins tested, fungus growth with riboflavin enhanced 2,2 times and 2,3 times with the mixture biotin and thiamin in relation to the control, without vitamin. In general, it was verified, after the incubation period, that the initial pH of the culture may enhance for up to 8,4. These results suggest that the studied variables may play important role in the growth of the organism in soil.