Isolation, identification and characterization of indigenous fungi for bioremediation of hexavalent chromium, nickel and cobalt
Nelis Hernahadini, Sony Suhandono, Devi N. Choesin, Siti K. Chaerun and Ade Kadarusman
School of Life Sciences and Technology, Institute Technology of Bandung, Indonesia.
Waste from nickel mining of Sorowako in South Sulawesi contains hexavalent chromium, nickeland cobalt metals in high concentration and may have a negative impact to the environment. Common waste treatment systems such as chemical treatment using a reducing reagent may still have a negative impact. Bioremediation using fungi or bacteria becomes more popular because it is an environmentally friendly alternative. The purposes of this study are to isolate and identify indigenous fungi that are resistant to heavy metals (hexavalent chromium, nickel,and cobalt) and are capable of reducing the concentration of metals in mining wastes. Ten fungal isolates were successfully isolated from the soils and pond sediments in the area ofnickel mining in Sorowako. Selection of superior isolate was carried out by growing all the isolates on PDA medium, which contained all of the three metals. One superior isolate was identified to be able to grow on medium with concentrations of 6400 ppm hexavalent chromium,200 ppm nickel and 50 ppm cobalt. Molecular identification and phylogenetic studies of the isolate using fungal PCR primers developed to amplify the ITS (internal transcribed spacer) region showed that the isolate sequence was very close to Trichoderma atroviride with 99.8% similarity. Optimum incubation time for the uptake of hexavalent chromium was 3 days, nickeland cobalt was 5 days, respectively, with an optimum pH of 4.