Novel integration strategy for enhancing chalcopyrite bioleaching by Acidithiobacillus sp in a 7-L fermenter

An integrated strategy (additional energy substrate-three stage pH control-fed batch) was firstly proposed for efficiently improving chalcopyrite bioleaching by Acidithiobacillus sp. in a 7-L fermenter. The strain adaptive-growing phase was greatly shortened from 8 days into 4 days with the supplement of additional 2 g/L Fe2+ + 2 g/L S-0. Jarosite passivation was effectively weakened basing on higher biomass via the three-stage pH-stat control (pH 1.3-1.0-0.7). The mineral substrate inhibition was attenuated by fed-batch fermentation. With the integrated strategy, the biochemical reaction was promoted and achieved a better balance. Meanwhile, the domination course of A. thiooxidans in the microbial community was shortened from 14 days to 8 days. As the results of integrated strategy, the final copper ion and productivity reached 89.1 mg/L and 2.23 mg/(L d), respectively, which was improved by 52.8% compared to the uncontrolled batch bioleaching. The integrated strategy could be further exploited for industrial chalcopyrite bioleaching. (C) 2014 Elsevier Ltd. All rights reserved.