Bioleaching Potential of Indigenous Bacterial Consortia from Gold-Bearing Sulfide Ore of Ta Nang Mine in Vietnam

Abstract

To date, bioleaching using bacterial consortia is widely regarded as an eco-friendly alternative to the traditional mining approaches due to its cost-effectiveness, feasibility, and sustainability. In the present study, for the first time, gold-bearing sulfide ore collected at Ta Nang mine, Vietnam was mineralogically characterized and subjected to bioleaching trial using indigenous bacterial consortia. The ore contains arsenopyrite, pyrite, galena, sphalerite, and chalcopyrite, of which the major metals were iron (4.78%), arsenic (1.73%), lead (0.43), and zinc (0.33%). After enrichment, a total of 19 iron-and sulfur-oxidizing bacteria were isolated and classified into six distinct genera including three previously described Bacillus, Pseudomonas, Acidithiobacillus, and three firstly reported heterotrophic Glutamicibacter, Providencia, and Stenotrophomonas from gold ore origin. Moreover, an autotrophic Acidithiobacillus sp. TNG6.3, sharing a 16S rRNA sequence of 95.1% identity with the closest sequence of the type strain A. caldus KU, represented a novel candidate species. The establishment of bioleaching utilizing enriched bacteria from gold ore consequently led to the removal of Ag (99.1%), Zn (37.9%), As (37.0%), and Fe (32.2%) from ore after 21 days of treatment, respectively. The present findings highlighted the potential of acidophilic bacteria originated from gold ores for extending applications in bioleaching of metals in Vietnam.