Notice of RetractionIsolation of Heterotrophic Microorganism Bacillus subtilis Lj86 for Improving Autotrophic Sulfur-Based Bioleaching of Metal-Polluted Sediments

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

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Sulfur-based bioleaching process using autotrophic Acidithiobacillus thiooxidans is a promising means in removing heavy metals from polluted sediments, but heavy metals removal efficiencies are often delayed due to the presence of toxic dissolved organic matter (DOM) in sediments. The objective of this study was therefore to improve heavy metals bioleaching efficiencies through introducing heterotrophic microorganism into the sulfur-based autotrophic sludge bioleaching system. An acid-tolerant strain Bacillus subtilis LJ86 was successfully isolated from the bioleached acidified sediments and it could grow well between pH 4.5 and 8.0, with optimum pH ~5.5. A marked improvement in the rate of sediment pH reduction was observed in the combined bioleaching experiment (co-inoculation of B. subtilis LJ86 and At. thiooxidans), resulting in the accelerated removals of Zn, Cu and Cr. Compared with 16 days required for maximum removal of various metals for the single bioleaching process (without inoculation of B. subtilis LJ86), the bioleaching period was greatly shorten to 10 days for the combined bioleaching process.