Isolation of a strain of Aspergillus fumigatus able to grow in minimal medium added with an industrial cyanide waste

The present note refers the results about the isolation of an Aspergillus fumigatus strain able to grow on an industrial cyanide waste as nitrogen source. The fungus was selected from an alkaline unpolluted soil in enrichment cultures in 50 ml of Minimal Medium added with 20 mmol glucose and supplemented initially with 0.1 mmol KCN and then with 70 mu l of a waste solution from a jewelry industry containing free cyanide and cyanide complexes of heavy metal ions including copper, silver, nickel, and others. The cyanide content of the waste was 1,500 ppm. The fungal growth was monitored determining dry weight, protein content and glucose consumption. The fungus efficiently utilized the cyanide as evidenced by the decrease in the inoculated medium of the compound under detection limits within 24 h and the concomitant growth within 15 days during which periodical additions of the waste to the cultures were made. The amount of the cyanide in the biomass of the fungus grown in presence of the waste was very scarce and comparable to that in absence of the pollutant. Furthermore the fungus was able to sequestrate metals such Ag, Cu, and Ni as a resistance mechanism against heavy metals. In conclusion our results are of interest for biodegradation plans of electroplating industrial wastes containing cyanide based pollutants.