Resistance to some Heavy Metals among Fungal Flora of Raw Refinery Effluent

Abstract

Investigations were carried out to assess the capacity of strains of fungi isolated from raw flowing effluent and effluent retention pond of Kaduna refinery plant to resist and grow in the presence of lead (Pb), nickel (Ni) and cadmium (Cd) invitro. Fungi belonging to the genera including Aspergillus spp., Penicillium spp., Fusarium spp., Curvularia spp. and Nigrospora spp. were isolated from the study sites. The isolates were inoculated into duplicate 100ml flask containing 50ml of potato dextrose broth (PDB) supplemented with 5,10 and 15ppm of Pb, Ni, and Cd. Each test isolate was inoculated into duplicate flask containing the same medium without the heavy metals to serve as control. All inoculated flasks were incubated aerobically at room temperature on a rotator shaker for 7days. The mycelial mats were harvested by filtering the cultures through preweighed filter paper (No.1). The filters bearing the mycelial mats were dried in an oven at 70^oC for 18hours. It was observed that most of the isolates tested resisted and grew in the medium containing 5 to 15ppm of tested heavy metals. Yield of dry mycelia mats in the heavy metal supplemented medium were also comparable to those grown in heavy metal free PDB medium. It was concluded that, these genera of fungi could be playing an important role in the removal of these metals usually present in the raw effluent during the period of residency in the retention pond through bioaccumulation. ©JASEM

Keywords: Fungal flora, Heavy metals, Resistance, Refinery effluents