Re-inoculated Bacteria Driving Microbial Community Functional Response to Bioleaching of Low-Grade Copper Sulfide Ores: Potential to Improve Copper Recovery

Low-grade ores generated by mining activities can lead to resource waste and environment pollution, which is of great concern. Thus, low-grade copper sulfide ores bioleaching is investigated in this study by re-inoculating bacteria at different intervals. The highest bacteria concentration of 5.830 x107 cells center dot mL(-1), improved attached bacteria proportion of 24.310% and copper recovery of 68.310% are obtained in sample re-inoculated bacteria both at days 1 and 4. More uniform distribution of dissolved oxygen is found in samples re-inoculated bacteria, compared with non- re-inoculated samples. 16S rDNA analysis shows that bacteria community structure is influenced significantly by re-inoculating bacteria at different intervals. Proportion of dominant species (Acidithiobacillus ferrooxidans) accounts for 97.653% when appropriate interval is applied in re-inoculating bacteria process. Based on the resulting data, possible reason for illustrating re-inoculating bacteria at appropriate interval to improve bioleaching of low-grade copper sulfide ores is put forward. [GRAPHICS] [GRAPHICS]

Automated summary

Low-grade copper sulfide ores generated by mining activities can cause resource waste and environmental pollution. This study investigates the bioleaching of low-grade ores by re-inoculating bacteria at different intervals. The results show that re-inoculation at both day 1 and day 4 leads to the highest bacteria concentration, improved attached bacteria proportion, and copper recovery. The distribution of dissolved oxygen is also more uniform in samples with re-inoculated bacteria. 16S rDNA analysis reveals that the bacteria community structure is significantly influenced by the re-inoculation intervals. The dominant species, Acidithiobacillus ferrooxidans, accounts for 97.653% when an appropriate interval is applied.