Biological removing of Cadmium from contaminated media by fungal biomass of Trichoderma species

BACKGROUND Environment pollution by heavy metals is a global disaster and there are several cleaning methods including bioremediation. Trichoderma species inhibit the growth of pathogenic fungi and play a useful role in agriculture and ecosystem management. METHODS In this study, the removing of cadmium ions by three species of Trichoderma (T. asperellum, T. harzianum and T. tomentosum) were studied under different pH (5, 7, 9) and different concentrations of Cd (1, 100, 200 ppm) in liquid media containing potato extract and dextrose. Above mentioned fungal strains were cultured in the Cd-polluted media and the remaining amount of metal ions in the media was measured after two months growth, using atomic absorption. RESULTS Results showed that all three fungal species were able to reduce the amount of Cd in the all three pH of the medias; but their removal ability varies depending on the species and cultural conditions. T. asperellum was showed maximum removal efficiency of cadmium (76.17%), (10.75 mg/g, at fungal dry weight). Based on our results, the most removal efficiency of Cd ions for the fungal species was evaluated in the alkaline pH. CONCLUSIONS Trichoderma species are important fungi in decreasing of Cadmium ions. They have bioremediation potency under various pH and concentration conditions.