Using isothermal microcalorimetry to measure the metabolic activity of the mineral-associated microbial community in bioleaching

Makaula, Didi X.; Huddy, Robert J.; Fagan-Endres, Marijke A.; Harrison, Susan T.L.

doi:10.1016/j.mineng.2016.12.012

Cited by 9 publications

(4 citation statements)

References 31 publications

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“…The enhanced metabolic activity was postulated to be due to the greater sulphide content making it easier for microbial mineral interaction. The measured heat flows on these waste rock samples were lower than those achieved by the same microbial consortium on a pyrite concentrate containing 54% Fe and 41% S (430 mW m -2 ) that had been allowed to contact the mineral surface for an equivalent period, however, inoculated with lower microbial concentration in a flow-through system [11]. The results presented in Fig.…”

Section: Resultsmentioning

confidence: 75%

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Investigating the Microbial Metabolic Activity on Mineral Surfaces of Pyrite-Rich Waste Rocks in an Unsaturated Heap-Simulating Column System

Makaula

Huddy

Fagan-Endres

et al. 2017

SSP

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Microbial association with and colonisation of mineral surfaces plays a key role in enhancing the extraction of metals from ores during heap bioleaching processes. On the other hand, if uncontrolled, the same association can also lead to the generation of acid rock drainage (ARD) effluents from mine waste. This study aims to measure microbial metabolic activity of a mixed mesophilic culture on the surfaces of pyrite-bearing waste rocks of different grades over time. The waste rocks are milled, size fractionated and coated onto glass beads, to provide a defined surface area. The metabolic activity on the mineral surface is measured with isothermal microcalorimetry (IMC) complemented with scanning electron microscopy (SEM) and analysis of solution chemistry to measure leach agents and metal release into the pregnant leach solution (PLS). The waste rock samples showed a similar degree of leaching when the solution chemistry was analysed, despite having different sulphide content. However, when metabolic activity of the micro-organisms on the mineral surface was measured, greater activity was seen with higher sulphide content. This data informs an ongoing study to establish a flow-through configuration of the biokinetic test for ARD prediction accounting for both leach solution and microbial-mineral interaction as well as differing kinetics of acid-neutralising and generating reactions to enable the refinement of the current batch method.

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Section: Resultsmentioning

confidence: 75%

“…The biotic conditions were inoculated with 10 8 cells/ml. Each flask was loaded with 100 6 mm beads coated with the respective mineral waste rock to provide a fixed surface area [11]. The pH and redox potential measurements and iron assays were performed regularly.…”

Section: Methodsmentioning

confidence: 99%

Investigating the Microbial Metabolic Activity on Mineral Surfaces of Pyrite-Rich Waste Rocks in an Unsaturated Heap-Simulating Column System

Makaula

Huddy

Fagan-Endres

et al. 2017

SSP

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“…Samples were collected at different operation times for each microorganism’s quantification and transcriptomic analyses ( Table 1 ). Notwithstanding the relevant metabolic activity previously observed on mineral-associated bacteria [ 33 , 34 ] and its recognized effect on mineral dissolution [ 35 ], mineral samples were neither obtained nor analyzed in this work. That decision was taken regarding the research work scope, which was to develop molecular markers for monitoring a mining operation where it is not possible to get representative mineral samples for periodic assessment [ 12 ].…”

Section: Methodsmentioning

confidence: 99%

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

Marín

Cortés

Acosta

et al. 2021

Genes

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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.

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“…These compounds may accidentally enter into the production chain and inhibit bacterial activity (unpublished data). Similarly, several scholars are using cutting-edge technology to understand the irrigation and colonization of bio-heaps [110,111]. On the other hand, studies on the bioleaching from polymetallic sources and of rare elements are also part of the scientific discussion [112,113].…”

Section: Challenges and Prospective Of Biohydrometallurgymentioning

confidence: 99%

Experiences and Future Challenges of Bioleaching Research in South Korea

et al. 2016

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This article addresses the state of the art of bioleaching research published in South Korean Journals. Our research team reviewed the available articles registered in the Korean Citation Index (KCI, Korean Journal Database) addressing the relevant aspects of bioleaching. We systematically categorized the target metal sources as follows: mine tailings, electronic waste, mineral ores and metal concentrates, spent catalysts, contaminated soil, and other materials. Molecular studies were also addressed in this review. The classification provided in the present manuscript details information about microbial species, parameters of operation (e.g., temperature, particle size, pH, and process length), and target metals to compare recoveries among the bioleaching processes. The findings show an increasing interest in the technology from research institutes and mineral processing-related companies over the last decade. The current research trends demonstrate that investigations are mainly focused on determining the optimum parameters of operations for different techniques and minor applications at the industrial scale, which opens the opportunity for greater technological developments. An overview of bioleaching of each metal substrate and opportunities for future research development are also included.

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Using isothermal microcalorimetry to measure the metabolic activity of the mineral-associated microbial community in bioleaching

Cited by 9 publications

References 31 publications

Investigating the Microbial Metabolic Activity on Mineral Surfaces of Pyrite-Rich Waste Rocks in an Unsaturated Heap-Simulating Column System

Investigating the Microbial Metabolic Activity on Mineral Surfaces of Pyrite-Rich Waste Rocks in an Unsaturated Heap-Simulating Column System

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

Experiences and Future Challenges of Bioleaching Research in South Korea

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