Isolation and characterization of mineral oxidizing bacteria from the Sarcheshmeh and Darezar mining sites, Iran

摘要

Hydrometallurgical processes based on bacterial leaching / solvent extraction / electro- wining are increasingly applied worldwide. Particularly for the recovery of copper from low-grade sulfide ores which are otherwise wasted. Depending upon the characteristics of the deposits and the ore, the technology is applied in different ways: heap leaching and in situ leaching . As a part of our contract with NICICO for development of bioleaching process in Sarcheshmeh mining site, a total number of 160 copper ore samples were collected from different part of the mine. Isolation of the organisms was made using 9K-enrichment medium and the bacteria identified using morphological, cultural and biochemical tests. Three important types of acid leaching bacteria: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans were isolated. A total of 60 bacteria were isolated and their oxidation rates for different samples were evaluated. Attempts have also been made to isolate thermophilic bacteria. The selected bacteria were also adapted for higher copper concentration resistance. The oxidation rate of selected bacteria was evaluated and hydrodynamic and kinetic parameters in a group of bench-scale glass columns were determined.