Efficiency of Aspergillus niger, Aspergillus flavus and Microsporum nanum to Remove Heavy Metals from Refinery Effluent

Abstract

The study was carried out to investigate the capability of some fungal species to remove heavy metals (Pb, Zn, Cr and Cd) from Kaduna Refinery and Petrochemical Company (KRPC) effluent. The three most tolerant fungi (Aspergillus niger, Aspergillus flavus and Microsporum nanum) isolated from the refinery effluent in a previous study were used for the removal of heavy metals. A seven (7) day old spore suspension of A. niger, A. flavus and M. nanum were inoculated in the medium of 250 ml Erlenmeyer’s flask containing 100 ml of effluent, enriched with 15 ml of peptone water and 1% (5 ml) of glucose as carbon source. Inoculated samples were incubated at 27 with control containing 100 ml effluent without fungi spores. All the flasks were incubated at 27  for 240 hours in a rotary shaker (150 rpm) to check fungal growth and its uptake and removal abilities. The removal level was determined using Atomic Absorption Spectrophotometer (AAS) before and after inoculation of the effluents with the three most tolerant fungal isolates (A. niger, A. flavus and M. nanum). A. niger showed removal efficiency of Cd (90.72%), followed by Zn (72.40%), Pb (67.23%) and Cr (51.25%) in that order. M. nanum removed high percentage of Cd (87.83%), followed by Pb (74.09), Zn (64.51%) and (46.99%). A. flavus showed high removal efficiency of Cd (87.63%), followed by Zn (64.63%), Pb (64.195) and Cr (49.66%). The results suggest that  A. niger, A. flavus and M. nanum indigenous to refinery effluent could be used in bioremediation works to remove heavy metals.