1- The objective of the present investigation was to isolate and identify the metal tolerance fungi from different polluted habitat.
2- Nine fungal isolates were isolated from different industrial areas, and only four fungal species were appeared whed they were isolated on Czapek’s Dox agar medium supplemented with silver (10mg/L) and chromium (100mg/L).
3- The more commen fungal species were tested for their tolerance to different concentrations of silver (10-1000mg/L) and chromium (50-2000mg/L).
4- Aspergillus niger and Aspergillus terreus were the only isolates which gave the highest tolerance to different concentrations of silver and chromium.
5- A.niger could tolerate chromium and silver in the growth medium up to 2000mg Cr/L and 800mg Ag/L, while A.terreus was able to grow in the presence of chromium and silver in the growth medium up to 2000mgCr/L and 200mg Ag/L respectively.
6- The growth of both fungal species was decreased with increasing Ag and Cr in the growth medium.
7- The effect of different carbon sources on the fungal growth and metal tolerance indicated that, starch and sucrose resulted in the highest growth and tolerance to metals by A.niger and A.terreus respectively.
8- The effect of different nitrogen sources on the fungal growth and metal tolerance indicated that, peptone and asparagine resulted in the highest growth and tolerance to metals by A.niger and A.terreus respectively.
9- The effect of different pH values on the fungal growth and metal tolerance indicated that, the growth of both fungi and tolerance to metals was increased with increasing pH value of the growth medium and reaching its maximum value at pH 6.0 and 5.0 for A.niger and A.terreus respectively.
10- The effect of different incubation temperatures on the fungal growth and metal tolerance indicated that, the best temperature gave the highest growth and tolerance to metals by A.niger and A.terreus was 30oC.
11- Total proteins, lipids and carbohydrates of whole mycelia and cell walls of A.niger and A.terreus grown in the presence of different chromium concentrations were slightly increased at 400 mg Cr/L and then decreased above this concentration.
12- Total lipids and carbohydrates of whole mycelia and cell walls of A.niger and A.terreus grown in the presence of different silver concentrations were increased with increasing silver concentration in the growth medium whereas, total proteins slightly increased at 200mg Ag/L and decreased above this concentration.
13- The biosorption of chromium and silver by fresh and dry biomass of A.niger and A.terreus was affected by several experimental conditions such as contact time, initial metal concentration, pH, and temperature and biomass concentration in the reaction mixture.
14- Fungal biomass grown in the presence of 200mg Cr/L and (20,200mgAg/L) for A.terreus and A.niger could rebind different individual metals such as Pb, Cu, Zn, Co and Fe higher than control.
15- The fungal biomasses were treated physically and chemically for increasing their biosorption capacity. The maximum biosorption capacity of Cr by both fungi resulted from acid treatment followed by alkali treatment and the minimum biosorption capacity achieved by heating treatment.
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