Validation of Genetic Markers Associated to Oxygen Availability in Low-Grade Copper Bioleaching Systems: An Industrial Application

Cortés, Mayra; Marín, Sabrina; Galleguillos, Pedro A.; Cautivo, Dina; Demergasso, Cecilia

doi:10.3389/fmicb.2019.01841

Cited by 5 publications

(7 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CBAR13) and the metabolisms involved in microbial responses to changes in the heap environment that affects the process performance. Oxygen reduction, CO 2 and N 2 fixation, ammonium transport, iron, and sulfur oxidation, and response to osmotic stress were the metabolisms selected regarding the results of previous research in the system [ 7 , 8 , 10 , 11 ].…”

Section: Methodsmentioning

confidence: 99%

“…All used primers were empirically validated in their specificity, repeatability, and sensibility, as described previously [ 11 ]. Pearson’s (R) coefficients of 0.99 and optimal efficiencies (E) (100–110%) [ 41 ] were obtained for all selected primers ( Table S1 ).…”

Section: Methodsmentioning

confidence: 99%

“…The fold-change gene expression (ratio) was calculated by the Pfaffl model using REST software V2.0.13 [ 42 ]. The Pfaffl model has been successfully used in previous gene expression analyses for acidophilic microorganisms [ 6 , 9 , 11 ]. One sample of each sample-set was selected and used as a control sample.…”

Section: Methodsmentioning

confidence: 99%

“…RNA was isolated, and reverse transcription was performed as previously described [9,11]. Transcription dynamics of five At.…”

Section: Rna Isolation and Transcriptional Analysismentioning

confidence: 99%

“…One of the main issues of bioleaching at the mine site is the close control required of acidity, air and nutrients availability, temperature, water quality, and cell activity, among other variables, for better metallurgical performances [ 6 , 7 , 8 , 9 , 10 , 11 ]. However, it is not feasible to monitor these variables inside ROM industrial permanent heaps, as argued before [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

From Laboratory towards Industrial Operation: Biomarkers for Acidophilic Metabolic Activity in Bioleaching Systems

Marín

Cortés

Acosta

et al. 2021

Genes

Self Cite

View full text Add to dashboard Cite

In the actual mining scenario, copper bioleaching, mainly raw mined material known as run‐of‐mine (ROM) copper bioleaching, is the best alternative for the treatment of marginal resources that are not currently considered part of the profitable reserves because of the cost associated with leading technologies in copper extraction. It is foreseen that bioleaching will play acomplementary role in either concentration—as it does in Minera Escondida Ltd. (MEL)—or chloride main leaching plants. In that way, it will be possible to maximize mines with installed solvent‐extraction and electrowinning capacities that have not been operative since the depletion of their oxide ores. One of the main obstacles for widening bioleaching technology applications is thelack of knowledge about the key events and the attributes of the technology’s critical events at the industrial level and mainly in ROM copper bioleaching industrial operations. It is relevant to assess the bed environment where the bacteria–mineral interaction occurs to learn about the limiting factors determining the leaching rate. Thus, due to inability to accurately determine in‐situ key variables, their indirect assessment was evaluated by quantifying microbial metabolic‐associated responses. Several candidate marker genes were selected to represent the predominant components of the microbial community inhabiting the industrial heap and the metabolisms involved in microbial responses to changes in the heap environment that affect the process performance. The microbial community’s predominant components were Acidithiobacillus ferrooxidans, At. thiooxidans, Leptospirillum ferriphilum, and Sulfobacillus sp. Oxygen reduction, CO2 and N2 fixation/uptake, iron and sulfur oxidation, and response to osmotic stress were the metabolisms selected regarding research results previously reported in the system. After that, qPCR primers for each candidate gene were designed and validated. The expression profile of the selected genes vs. environmental key variables in pure cultures, column‐leaching tests, and the industrial bioleaching heap was defined. We presented the results obtained from the industrial validation of the marker genes selected for assessing CO2 and N2 availability, osmotic stress response, as well as ferrous iron and sulfur oxidation activity in the bioleaching heap process of MEL. We demonstrated that molecular markers are useful for assessing limiting factors like nutrients and air supply, and the impact of the quality of recycled solutions. We also learned about the attributes of variables like CO2, ammonium, and sulfate levels that affect the industrial ROM‐scale operation.

show abstract