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The effects of metabolites from the indigenous Acidithiobacillus thiooxidans and temperature on the bioleaching of cadmium from soil
Author(s) -
Liu HsuanLiang,
Chiu ChiWei,
Cheng YangChu
Publication year - 2003
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10714
Subject(s) - bioleaching , leaching (pedology) , chemistry , cadmium , sulfuric acid , acidithiobacillus thiooxidans , acidithiobacillus ferrooxidans , metallurgy , environmental chemistry , nuclear chemistry , soil water , inorganic chemistry , materials science , biology , organic chemistry , copper , ecology
The effect of metabolites from the indigenous Acidithiobacillus thiooxidans and temperature on the bioleaching of cadmium from soil was investigated in the present study. Bioleaching was found to be more effective than chemical leaching of cadmium. The metabolite, mainly sulfuric acid, which was shown to be growth‐associated in the exponential phase, plays a major role in bioleaching. The maximum amount of cadmium leached was obtained after 8 days of precultivation when cells were directly involved in the leaching process. It indicates that cells in the exponential growth phase exhibit higher activity toward bioleaching. In contrast, the maximum amount of cadmium leached and the maximum initial rate for bioleaching were reached after 16 days of precultivation when only metabolites were involved in the bioleaching process. It implies that higher sulfuric acid concentration results in higher leaching efficiency. In addition, higher temperature leads to higher leaching efficiency. The optimal operation condition for bioleaching was determined to be a two‐stage process: The first stage involves the precultivation of the indigenous A. thiooxidans at 30°C for 8 days followed by 20 minutes of centrifugation to discard cells. The second stage involves the bioleaching with the subsequent supernatant at 50°C. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 638–645, 2003.