Comparison of bioleaching of chalcopyrite concentrates with mixed culture after cryopreservation with PEG-2000 in liquid nitrogen

Abstract A mixed culture of bioleaching microorganisms was enriched. Then the mixed culture was preserved by liquid nitrogen cryopreservation for 6 months and 12 months, respectively, using PEG-2000 as the protective agent. The chalcopyrite leaching ability, activity and diversity of the mixed cultu...
Ausführliche Beschreibung

Abstract A mixed culture of bioleaching microorganisms was enriched. Then the mixed culture was preserved by liquid nitrogen cryopreservation for 6 months and 12 months, respectively, using PEG-2000 as the protective agent. The chalcopyrite leaching ability, activity and diversity of the mixed culture before and after preservation were compared. The results showed that the copper extraction rate was 95.7% in chalcopyrite bioleaching within 20 d by the original culture. After cryopreservation for 6 months and 12 months, the copper extraction rate of the mixed culture was 94.9% within 25 d and 93.6% within 35 d, respectively. The cell viability achieved 87% and 41% after being preserved for 6 months and 12 months, respectively. Furthermore, the ecology analysis identified Acidithiobacillus ferrooxidans, Acidithiobacillus caldus, Sulfobacillus thermotolerans and Pseudomonas aeruginosa in the original mixed culture. After cryopreservation for 12 months, the composition of community changed, but the predominant microorganisms still existed. Ausführliche Beschreibung