Effects of dissolved oxygen and carbon dioxide under oxygen-rich conditions on the biooxidation process of refractory gold concentrate and the microbial community

Wang, Hong; Zhang, Xu; Zhu, Mingming; Tan, Wen‐Song

doi:10.1016/j.mineng.2015.06.016

Cited by 12 publications

(5 citation statements)

References 26 publications

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“…The DO level which affects negatively the efficiency of bioleaching with the KCC consortium is quite different from those previously mentioned in the literature which reports an inhibitory effect for much lower DO levels. Especially this study can be compared to the results published recently by Wang et al (2015) which studied the effect of dissolved oxygen on bioleaching using a sulfidic material and a microbial community similar to the ones used in this study. The optimum activity of the microbial population was obtained at 3.75 ppm concentration of DO.…”

Section: Discussionmentioning

confidence: 86%

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Influence of dissolved oxygen on the bioleaching efficiency under oxygen enriched atmosphere

Guézennec

Joulian

Jacob

et al. 2017

Minerals Engineering

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The use of oxygen enriched air is a common practice in high-temperature bioleaching tests (> 70°C) to overcome oxygen solubility limitation and reduced the energy costs of the process. Air is usually preferred in medium and low-temperature operations mainly for technical and economic constraints. Nevertheless, under high-sulfide loading conditions -high-grade metal sulfide concentrates and high solids concentration -the microbial and chemical demand for oxygen is significantly increased during the bioleaching process. If not satisfied, this high oxygen demand might limit the oxidation efficiency. Therefore it requires the injection of large amounts of air. Sparging with oxygen enriched gas instead of air may offer an interesting alternative process option to improve gas transfer in the bioleaching reactor and to provide an adequate oxygen supply in order to satisfy the oxygen demand. It might be useful to develop innovative alternative to the classical stirred tank reactor (STR) technology. However, the use of such conditions can lead to much higher dissolved oxygen (DO) concentrations than those encountered with air. Very few papers have been devoted to the study of the optimal range of DO concentrations for bioleaching processes. Most of them reported an inhibitory effect of DO concentrations above 5 ppm. The purpose of this study was to investigate the influence of DO on the bioleaching efficiency under oxygen-enriched atmosphere in 21 L stirred tank reactor at 42°C. Bioleaching experiments were performed in continuous mode with sulfide-rich tailings wastes composed mainly of pyrite (51%) and quartz using the "BRGM-KCC" bacterial consortia. The solid load was close to 20% (w/w). Using various oxygen supply conditions (partial pressure, gas rate), the DO concentration in the reactor varied between 4 and 17 ppm. For a DO ranging from 4 to 13 ppm, a good bacterial oxidizing activity was observed and the sulfide dissolution efficiency increased with the DO concentration. It is assumed that this improvement of the bioleaching efficiency was linked to an increase of the oxygen transfer rate from the gas phase to the liquid phase rather than a direct effect of the DO level. When the DO concentration reached 17 ppm a significant decrease of the microbial activity and consequently of the oxygen consumption was noticed. These results show that there is a critical value above which the DO concentration is detrimental to the activity of the bioleach microorganisms present in the "BRGM-KCC" consortia but this value is much higher than the one usually mentioned in the literature.

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Section: Discussionmentioning

confidence: 86%

“…Very few papers have been devoted to the study of the optimal range of DO concentrations for bioleaching processes. However most of them reported an inhibitory effect of DO concentrations above 5 ppm (de Kock et al, 2004;Wang et al, 2015).…”

Section: Ro2 = Kla × (C* -Cl)mentioning

confidence: 99%

Influence of dissolved oxygen on the bioleaching efficiency under oxygen enriched atmosphere

Guézennec

Joulian

Jacob

et al. 2017

Minerals Engineering

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“…Bioleaching efficiency can be affected by many factors. Besides bacterial species and energy sources (Sugio et al, 1989;Bajestani et al, 2014), factors such as pH (Li et al, 2013), dissolved oxygen (DO), dissolved CO 2 (Wang et al, 2015), mineral/solid waste particle size (Jones et al, 2011), and metal ion concentration (e.g., Ni 2+ , V 4+ , Mo 6+ ) (Pradhan et al, 2009) have also been investigated by researchers. It was found that a higher bioleaching capacity could be obtained from mixed cultures of some acidophilic bacteria (Ilyas and Lee, 2015) compared with using pure-strain bacteria, owing to synergistic effects.…”

Section: Fe 2+mentioning

confidence: 99%

“…The bacterial intracellular ROS content in the simulated bioleaching systems at different time was detected using an ROS assay kit (Farrell et al, 2011) following a reported experimental method (Wang et al, 2015). Five milliliters of slurry was centrifuged at 450 g for 10 min to harvest free cells and pyrite particles.…”

Section: Detection Of Intracellular Ros Content In the Presence Of LImentioning

confidence: 99%

Oxidative Stress Induced by Metal Ions in Bioleaching of LiCoO2 by an Acidophilic Microbial Consortium

Liu

Líu

et al. 2020

Front. Microbiol.

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An acidophilic microbial consortium (AMC) was used to investigate the fundamental mechanism behind the adverse effects of pulp density increase in the bioleaching of waste lithium ion batteries (WLIBs). Results showed that there existed the effect of metal-ion stress on the bio-oxidative activity of AMC. The Li + and Co 2+ accumulated in the leachate were the direct cause for the decrease in lithium and cobalt recovery yields under a high pulp density. In a simulated bioleaching system with 4.0% (w •v −1) LiCoO 2 , the intracellular reactive oxygen species (ROS) content in AMC increased from 0.82 to 6.02 within 24 h, which was almost three times higher than that of the control (2.04). After the supplementation of 0.30 g•L −1 of exogenous glutathione (GSH), the bacterial intracellular ROS content decreased by 40% within 24 h and the activities of intracellular ROS scavenging enzymes, including glutathione peroxidase (GSH-Px) and catalase (CAT), were 1.4-and 2.0-folds higher in comparison with the control within 24 h. In the biofilms formed on pyrite in the bioleaching of WLIBs, it was found that metal-ion stress had a great influence on the 3-D structure and the amount of biomass of the biofilms. After the exogenous addition of GSH, the structure and the amount of biomass of the biofilms were restored to some extent. Eventually, through ROS regulation by the exogenous addition of GSH, very high metal recovery yields of 98.1% Li and 96.3% Co were obtained at 5.0% pulp density.

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“…M14 and the efficiency of arsenic biooxidation, as were our preliminary experiments in batch cultures (data not shown). Indeed, many studies have observed a positive correlation between the density of bacteria and the rate of metal metabolism or biotransformation for arsenic compounds and other elements [ 80 , 81 , 82 ].…”

Section: Resultsmentioning

confidence: 99%

Genomic and Biotechnological Characterization of the Heavy-Metal Resistant, Arsenic-Oxidizing Bacterium Ensifer sp. M14

diCenzo

Debiec

Krzysztoforski

et al. 2018

Genes

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Ensifer (Sinorhizobium) sp. M14 is an efficient arsenic-oxidizing bacterium (AOB) that displays high resistance to numerous metals and various stressors. Here, we report the draft genome sequence and genome-guided characterization of Ensifer sp. M14, and we describe a pilot-scale installation applying the M14 strain for remediation of arsenic-contaminated waters. The M14 genome contains 6874 protein coding sequences, including hundreds not found in related strains. Nearly all unique genes that are associated with metal resistance and arsenic oxidation are localized within the pSinA and pSinB megaplasmids. Comparative genomics revealed that multiple copies of high-affinity phosphate transport systems are common in AOBs, possibly as an As-resistance mechanism. Genome and antibiotic sensitivity analyses further suggested that the use of Ensifer sp. M14 in biotechnology does not pose serious biosafety risks. Therefore, a novel two-stage installation for remediation of arsenic-contaminated waters was developed. It consists of a microbiological module, where M14 oxidizes As(III) to As(V) ion, followed by an adsorption module for As(V) removal using granulated bog iron ores. During a 40-day pilot-scale test in an abandoned gold mine in Zloty Stok (Poland), water leaving the microbiological module generally contained trace amounts of As(III), and dramatic decreases in total arsenic concentrations were observed after passage through the adsorption module. These results demonstrate the usefulness of Ensifer sp. M14 in arsenic removal performed in environmental settings.

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Effects of dissolved oxygen and carbon dioxide under oxygen-rich conditions on the biooxidation process of refractory gold concentrate and the microbial community

Cited by 12 publications

References 26 publications

Influence of dissolved oxygen on the bioleaching efficiency under oxygen enriched atmosphere

Influence of dissolved oxygen on the bioleaching efficiency under oxygen enriched atmosphere

Oxidative Stress Induced by Metal Ions in Bioleaching of LiCoO2 by an Acidophilic Microbial Consortium

Genomic and Biotechnological Characterization of the Heavy-Metal Resistant, Arsenic-Oxidizing Bacterium Ensifer sp. M14

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