Research in microbiology最新文献

{"title":"The dynamics of two iron-oxidizing Acidithiobacillus strains in industrial copper sulfide heap-leaching","authors":"Camila Escuti ,&nbsp;Roberto Véliz ,&nbsp;Mauricio Acosta ,&nbsp;Alex Echeverría-Vega ,&nbsp;Gonzalo Araya ,&nbsp;Diego Ayma ,&nbsp;Cecilia Demergasso","doi":"10.1016/j.resmic.2023.104168","DOIUrl":"10.1016/j.resmic.2023.104168","url":null,"abstract":"<div><p>Several species within the <em>Acidithiobacillus</em> (At.) genus can derive energy from oxidizing ferrous iron and sulfur. Two bacterial strains according to their 16S rRNA gene sequences closely related to <em>A</em><em>t</em>. <em>ferridurans</em> and <em>At. ferrivorans</em> were obtained from the industrial sulfide heap leaching process at Minera Escondida (SLH), named D2 and DM, respectively. We applied statistical and data mining analyses to the abundance of <em>At. ferridurans</em> D2 and <em>At. ferrivorans</em> DM taxa in the industrial process over 16 years of operation. In addition, we performed phylogenetic analysis and genome comparison of the type strains, as well as culturing approaches with representative isolates of <em>At. ferridurans</em> D2 and <em>At. ferrivorans</em> DM taxa to understand the differential phenotypic features. Throughout the 16 years, two main operational stages were identified based on the D2 and DM taxa predominance in solution samples. The better suitability of <em>At. ferrivorans</em> DM to grow in a wide range of temperature and in micro-oxic environments, and to oxidize S by reducing Fe(III) revealed through culturing approaches can, in a way, explain the taxa distribution in both operational stages. The isolate <em>At. ferridurans</em> D2 could be considered as a specialist in aerobic sulfur oxidation, while isolate <em>At. ferrivorans</em> DM is a specialist in iron oxidation. In addition, the results from ore samples occasionally obtained from the industrial heap suggest that <em>At. ferridurans</em> D2 abundance was more related to its abundance in the solution samples than <em>At. ferrivorans</em> DM was. This dynamic coincides with previously obtained results in in-lab cell-mineral attaching experiments with both strains. This information increases our knowledge the ecophysiology of <em>Acidithiobacillus</em> and of the importance of diverse physiological traits at industrial bioleaching scales.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104168"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823001432/pdfft?md5=7118de03996d368ba954475c56b7103e&pid=1-s2.0-S0923250823001432-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138299847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative genomics sheds light on transcription factor-mediated regulation in the extreme acidophilic Acidithiobacillia representatives","authors":"Pedro Sepúlveda-Rebolledo ,&nbsp;Carolina González-Rosales ,&nbsp;Mark Dopson ,&nbsp;Ernesto Pérez-Rueda ,&nbsp;David S. Holmes ,&nbsp;Jorge H. Valdés","doi":"10.1016/j.resmic.2023.104135","DOIUrl":"10.1016/j.resmic.2023.104135","url":null,"abstract":"<div><p>Extreme acidophiles thrive in acidic environments, confront a multitude of challenges, and demonstrate remarkable adaptability in their metabolism to cope with the ever-changing environmental fluctuations, which encompass variations in temperature, pH levels, and the availability of electron acceptors and donors. The survival and proliferation of members within the <em>Acidithiobacillia</em> class rely on the deployment of transcriptional regulatory systems linked to essential physiological traits. The study of these transcriptional regulatory systems provides valuable insights into critical processes, such as energy metabolism and nutrient assimilation, and how they integrate into major genetic-metabolic circuits. In this study, we examined the transcriptional regulatory repertoires and potential interactions of forty-three <em>Acidithiobacillia</em> complete and draft genomes, encompassing nine species. To investigate the function and diversity of Transcription Factors (TFs) and their DNA Binding Sites (DBSs), we conducted a genome-wide comparative analysis, which allowed us to identify these regulatory elements in representatives of <em>Acidithiobacillia</em>. We classified TFs into gene families and compared their occurrence among all representatives, revealing conservation patterns across the class. The results identified conserved regulators for several pathways, including iron and sulfur oxidation, the main pathways for energy acquisition, providing new evidence for viable regulatory interactions and branch-specific conservation in <em>Acidithiobacillia</em>. The identification of TFs and DBSs not only corroborates existing experimental information for selected species, but also introduces novel candidates for experimental validation. Moreover, these promising candidates have the potential for further extension to new representatives within the class.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104135"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823001109/pdfft?md5=38238f74fdda79410ebbbb3969ac016f&pid=1-s2.0-S0923250823001109-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10185051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioleaching of polymetallic sulphidic mining residues: influence of increasing solid concentration on microbial community dynamics and metal dissolution","authors":"Catherine Joulian,&nbsp;Agathe Hubau,&nbsp;Douglas Pino-Herrera,&nbsp;Anne-Gwénaëlle Guezennec","doi":"10.1016/j.resmic.2023.104112","DOIUrl":"10.1016/j.resmic.2023.104112","url":null,"abstract":"<div><p>Within the European research project NEMO, a bioleaching strategy was developed for efficient metal extraction from bioleach residue currently heap-leached at Sotkamo (Finland) that still contains sulphidic minerals and valuable metals (Ni, Zn, Co, Cu). The strategy of gradually increasing the solid content with 5% steps allowed the adaptation of the consortium up to 20% (w/w) solid content, with efficient metal dissolution and same dominant bacteria. Largest proportions of <em>Sulfobacillus</em> <em>thermosulfidooxidans</em> while Eh increased suggested it to be most involved in iron oxidation. <em>Acidithiobacillus</em> <em>caldus</em> was rather found when pH stabilized, in line with a production of protons from sulphur oxidation that maintained low pH. ‘<em>Acidithiomicrobium</em>’ P2 was favoured towards the end of the runs and at 20% (w/w) solids possibly due to its tolerance to Ni. The use of gene abundance to evaluate biomass in the pulp provided complementary results to classical cell counts in the liquid phase, and suggested a key role of bacteria associated to mineral particles in iron oxidation. Scaling-up in 21-L stirred-tank reactor at 20% (w/w) solids had no detrimental effect on bioleaching and confirmed metal extraction rates. ‘<em>Acidithiomicrobium</em>’ P2 and <em>Sb. thermosulfidooxidans</em> remained main actors. However, the biological activity was considerably reduced at 30% (w/w) solid concentration, which may be due to a too drastic environmental change for the bacteria to adapt to higher solid concentration. Efficient bioleaching of Sotkamo bioleaching residue at high solid concentration was demonstrated, as well as the robustness of the selected moderately thermophilic consortium, at laboratory and pilot scales.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104112"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823000876/pdfft?md5=ea1e3033d03269de5e4eb191e6b295dc&pid=1-s2.0-S0923250823000876-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10309766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sulfur oxidation kinetics of Acidithiobacillus caldus and its inhibition on exposure to thiocyanate present in cyanidation tailings wastewater","authors":"Catherine J. Edward,&nbsp;Mariette Smart,&nbsp;Athanasios Kotsiopoulos,&nbsp;Susan T.L. Harrison","doi":"10.1016/j.resmic.2023.104134","DOIUrl":"10.1016/j.resmic.2023.104134","url":null,"abstract":"<div><p>The sulfur oxidation kinetics of an industrial strain of <em>Acidithiobacillus caldus</em> (<em>At. caldus</em>) cultured on elemental sulfur was explored in batch experiments in the absence and presence of thiocyanate (SCN⁻), a toxin inherent within cyanidation tailings wastewater. The Contois rate expression accurately described <em>At. caldus</em> sulfate generation (R² &gt; 0.93) and microbial growth (R² &gt; 0.87). For a culture maintained at 45 °C a maximum specific growth rate (<span><math><mrow><msub><mi>μ</mi><mi>max</mi></msub></mrow></math></span>) of 0.105 h⁻¹, sulfate yield from biomass (<span><math><mrow><msub><mi>Y</mi><mrow><mi>p</mi><mi>x</mi></mrow></msub></mrow></math></span>) of 4.8 × 10⁻⁹ mg SO₄²⁻.cell⁻¹, and Contois affinity coefficient (<span><math><mrow><msub><mi>K</mi><mi>x</mi></msub></mrow></math></span>) of 1.56 × 10⁻⁸ mg S.cell⁻¹ were established. The presence of SCN⁻ (0 mg/L - 20 mg/L) in the bulk solution inhibited the microbial system competitively. Moreover, SCN⁻ impeded microbial growth differentially; the rate expression was therefore partitioned with respect to SCN⁻ concentration and inhibition constants (<span><math><mrow><msub><mi>K</mi><mi>i</mi></msub></mrow></math></span>) were determined for each region. Adaptation to discrete concentrations of SCN⁻ (1 mg/L and 20 mg/L) improved SCN⁻ tolerance in <em>At. caldus</em>; however, adapted strains exhibited reduced sulfur oxidation potential when cultured under thiocyanate-free conditions relative to the non-adapted control strain. To describe the adapted systems accurately, the Contois affinity coefficient (<span><math><mrow><msub><mi>K</mi><mi>x</mi></msub></mrow></math></span>) was revised to reflect the suspected metabolic decline. The derived <span><math><mrow><msub><mi>K</mi><mi>x</mi></msub></mrow></math></span> values increased in magnitude and affirmed an innate reduction in microbial substrate affinity or substrate adsorption capacity. Inclusion of these updated <span><math><mrow><msub><mi>K</mi><mi>x</mi></msub></mrow></math></span> constants within the rate equation suitably represented the experimental data for both adapted <em>At. caldus</em> strains with R² &gt; 0.94. Furthermore, the impact of adaptation on the inhibition kinetics and inhibition mechanism associated with SCN⁻ exposure were reviewed. Thiocyanate inhibited sulfur oxidation non-competitively in the adapted strains, and the shift in inhibition mechanism may be attributed to the compromised metabolic state following adaptation.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104134"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823001092/pdfft?md5=ab5d0b7bfee4b9d888a6bd7e62bea358&pid=1-s2.0-S0923250823001092-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41150869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rates of iron(III) reduction coupled to elemental sulfur or tetrathionate oxidation by acidophilic microorganisms and detection of sulfur intermediates","authors":"Anja Breuker,&nbsp;Axel Schippers","doi":"10.1016/j.resmic.2023.104110","DOIUrl":"10.1016/j.resmic.2023.104110","url":null,"abstract":"<div><p>Bioleaching processes and acid mine drainage (AMD) generation are mainly driven by aerobic microbial iron(II) and inorganic sulfur/compound oxidation. Dissimilatory iron(III) reduction coupled to sulfur/compound oxidation (DIRSO) by acidophilic microorganisms has been described for anaerobic cultures, but iron reduction was observed under aerobic conditions as well. Aim of this study was to explore reaction rates and mechanisms of this process. Cell-specific iron(III) reduction rates for different <em>Acidithiobacillus</em> (<em>At.</em>) strains during batch culture growth or stationary phase with iron(III) (∼40 mM) as electron acceptor and elemental sulfur or tetrathionate as electron donor (1% or 5 mM, respectively) were determined. The rates were highest under anaerobic conditions for the <em>At. ferrooxidans</em> type strain with 6.8 × 10⁶ and 1.1 × 10⁷ reduced iron(III) ions per second per cell for growth on elemental sulfur and tetrathionate, respectively. The iron(III) reduction rates were somehow lower for the anaerobically sulfur grown archaeon <em>Ferroplasma acidiphilum</em>, and lowest for the sulfur grown <em>At. caldus</em> type strain under aerobic conditions (1.7 × 10⁶ and 7.3 × 10⁴ reduced iron(III) ions per second per cell, respectively). The rates for five strains of <em>At. thiooxidans</em> (aerobe) were in between those for <em>At. ferrooxidans</em> (anaerobe) and <em>At. caldus</em> (aerobe). There was no pronounced pH dependence of iron(III) reduction rates in the range of pH 1.0–1.9 for the type strains of all species but rates increased with increasing pH for four other <em>At. thiooxidans</em> strains. Thiosulfate as sulfur intermediate was found for <em>At. ferrooxidans</em> during anaerobic growths on tetrathionate and iron(III) but not during anaerobic growths on elemental sulfur and iron(III), and a small concentration was measured during aerobic growths on tetrathionate without iron(III). For the <em>At. thiooxidans</em> type strain thiosulfate was found with tetrathionate grown cells under aerobic conditions in presence and absence of iron(III), but not with sulfur grown cells. Evidence for hydrogen sulfide production at low pH was found for the <em>At. ferrooxidans</em> as well as the <em>At. thiooxidans</em> type strains during microaerophilic growth on elemental sulfur and for <em>At. ferrooxidans</em> during anaerobic growths on tetrathionate and iron(III). The occurrence of sulfur compound intermediates supports the hypothesis that chemical reduction of iron(III) ions takes place by sulfur compounds released by the microbial cells.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104110"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823000852/pdfft?md5=113ed6974c2a60c49a0f98645f745eb4&pid=1-s2.0-S0923250823000852-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9943400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of element yield, bacterial community structure and the impact of carbon sources for bioleaching rare earth elements from high grade monazite","authors":"Melissa K. Corbett ,&nbsp;April Gifford ,&nbsp;Nick Fimognari ,&nbsp;Elizabeth L.J. Watkin","doi":"10.1016/j.resmic.2023.104133","DOIUrl":"10.1016/j.resmic.2023.104133","url":null,"abstract":"<div><p>Rare earth element (REE) recovery from waste streams, mine tailings or recyclable components using bioleaching is gaining traction due to the shortage and security of REE supply as well as the environmental problems that occur from processing and refining. Four heterotrophic microbial species with known phosphate solubilizing capabilities were evaluated for their ability to leach REE from a high-grade monazite when provided with either galactose, fructose or maltose. Supplying fructose resulted in the greatest amount of REE leached from the ore due to the largest amount of organic acid produced. Gluconic acid was the dominant organic acid identified produced by the cultures, followed by acetic acid. The monazite proved difficult to leach with the different carbon sources, with preferential release of Ce over La, Nd and Pr.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104133"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823001080/pdfft?md5=c629c7b62e1c20b070140e1adb7d68e8&pid=1-s2.0-S0923250823001080-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10178287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shedding light on the electron transfer chain of a moderately acidophilic iron oxidizer: characterization of recombinant HiPIP-41, CytC-18 and CytC-78 derived from Ferrovum sp. PN-J47-F6","authors":"Sophie R. Ullrich,&nbsp;Helena Fuchs,&nbsp;Michael Schlömann","doi":"10.1016/j.resmic.2023.104088","DOIUrl":"10.1016/j.resmic.2023.104088","url":null,"abstract":"<div><p>Efficient electron transfer from the donor to the acceptor couple presents a necessary requirement for acidophilic and neutrophilic iron oxidizers due to the low energy yield of aerobic ferrous iron oxidation. Involved periplasmic electron carriers are very diverse in these bacteria and show adaptations to the respective thermodynamic constraints such as a more positive redox potential reported for extreme acidophilic <em>Acidithiobacillus</em> spp. Respiratory chain candidates of moderately acidophilic members of the genus <em>Ferrovum</em> share similarities with both their neutrophilic iron oxidizing relatives and the more distantly related <em>Acidithiobacillus</em> spp. We examined our previous omics-based conclusions on the potential electron transfer chain in <em>Ferrovum</em> spp. by characterizing the three redox protein candidates CytC-18, CytC-78 and HiPIP-41 of strain PN-J47-F6 which were produced as recombinant proteins in <em>Eschericha coli.</em> UV/Vis-based redox assays suggested that HiPIP-41 has a very positive redox potential while redox potentials of CytC-18 and CytC-78 are more negative than their counterparts in <em>Acidithiobacillus</em> spp. Far Western dot blotting demonstrated interactions between all three recombinant redox proteins while redox assays showed the electron transfer from HiPIP-41 to either of the cytochromes. Altogether, CytC-18, CytC-78 and HiPIP-41 indeed represent very likely candidates of the electron transfer in <em>Ferrovum</em> sp. PN-J4-F6.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104088"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823000633/pdfft?md5=30ef0e7e14161084490db12e5d7eb88e&pid=1-s2.0-S0923250823000633-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9674595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulating compatible solute biosynthesis using a metabolic flux model of the biomining acidophile, Acidithiobacillus ferrooxidans ATCC 23270","authors":"Himel Nahreen Khaleque ,&nbsp;Hadi Nazem-Bokaee ,&nbsp;Yosephine Gumulya ,&nbsp;Ross P. Carlson ,&nbsp;Anna H. Kaksonen","doi":"10.1016/j.resmic.2023.104115","DOIUrl":"10.1016/j.resmic.2023.104115","url":null,"abstract":"<div><p>Halotolerant, acidophilic, bioleaching microorganisms are crucial to biomining operations that utilize saline water. Compatible solutes play an important role in the adaptation of these microorganisms to saline environments. <em>Acidithiobacillus ferrooxidans</em> ATCC 23270, an iron- and sulfur-oxidizing acidophilic bacterium, synthesizes trehalose as its native compatible solute but is still sensitive to salinity. Recently, halotolerant bioleaching bacteria were found to use ectoine as their key compatible solute. Previously, bioleaching bacteria were recalcitrant to genetic manipulation; however, recent advancements in genetic tools and techniques allow successful genetic modification of <em>A. ferrooxidans</em> ATCC 23270. Therefore, this study aimed to test, <em>in silico</em>, the effect of native and synthetic compatible solute biosynthesis by <em>A. ferrooxidans</em> ATCC 23270 on its growth and metabolism. Metabolic network flux modelling was used to provide a computational framework for the prediction of metabolic fluxes during production of native and synthetic compatible solutes by <em>A. ferrooxidans</em> ATCC 23270, <em>in silico</em>. Complete pathways for trehalose biosynthesis by the bacterium are proposed and captured in the updated metabolic model including a newly discovered UDP-dependent trehalose synthesis pathway. Finally, the effect of nitrogen sources on compatible solute production was simulated and showed that using nitrogen gas as the sole nitrogen source enables the ectoine-producing ‘engineered’ microbe to oxidize up to 20% more ferrous iron in comparison to the native microbe that only produces trehalose. Therefore, the predictive outcomes of the model have the potential to guide the design and optimization of a halotolerant strain of <em>A. ferrooxidans</em> ATCC 23270 for saline bioleaching operations.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104115"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823000906/pdfft?md5=e2ca8dfe1f5c3c7a492bbdffe6ec30ce&pid=1-s2.0-S0923250823000906-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9984930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial: Special issue on International Biohydrometallurgy Symposium (IBS) 2022","authors":"Elizabeth Watkin,&nbsp;Axel Schippers,&nbsp;Melissa Corbett","doi":"10.1016/j.resmic.2023.104174","DOIUrl":"10.1016/j.resmic.2023.104174","url":null,"abstract":"","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104174"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823001511/pdfft?md5=d54181ff290c80ab3c1ac1c0ba1c002c&pid=1-s2.0-S0923250823001511-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138885986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial immobilisation and adaptation to Cu2+ enhances microbial Fe2+ oxidation for bioleaching of printed circuit boards in the presence of mixed metal ions","authors":"Musa D. Maluleke,&nbsp;Athanasios Kotsiopoulos,&nbsp;Elaine Govender-Opitz,&nbsp;Susan T.L. Harrison","doi":"10.1016/j.resmic.2023.104148","DOIUrl":"10.1016/j.resmic.2023.104148","url":null,"abstract":"<div><p>A circular economy requires effective re-use of finite resources, such as metals from waste electrical and electronic equipment (WEEE). Bioleaching for extraction and recovery of base metals from printed circuit boards (PCBs) before recovering precious metals has potential to increase metal circularity. However, inhibition by base metals released from the PCBs and accumulated in PCB leachates on microbial Fe²⁺ oxidation, a critical bioleaching sub-process for Fe³⁺ regeneration, can limit this approach. Here, we explore the potential of microbial immobilisation on polyurethane foam (PUF) and adaptation to cupric ions to minimise inhibition by mixed metals released from PCBs, particularly zinc, nickel, and tin, and enhancing Fe²⁺ oxidation rates in PCB bioleaching systems. A mixed mesophilic culture dominant in <em>Leptospirillum ferriphilum, Acidiplasma cupricumulans</em> and <em>Acidithiobacillus caldus</em> was immobilised on PUF and adapted to 6 g/L Cu²⁺. Tolerance of Cu-adapted immobilised cells to the inhibitory metal ions Zn²⁺, Ni²⁺, and Sn²⁺, as individual (0–10 g/L) and mixed metal ions at concentrations typically leached from PCBs at solids loadings of 0–20% (mass/volume) was compared to that of non-adapted immobilised cells. Further, the impact of solutes from PCB leachates was evaluated. Inhibition by individual metal ions decreased in the order Sn²⁺ &gt; Ni²⁺ &gt; Zn²⁺. Inhibition of ferrous iron oxidation by mixed metal ions was synergistic with respect to individual metal ions. PCB leachates were more inhibitory than both mixed and individual metal ions even where metal concentration was low. Cu-adapted immobilised cells exhibited higher tolerance to increasing concentrations of inhibitory metal ions than non-adapted cells. These results are promising for the application of Cu-adapted cells in the bioleaching of PCBs and multi-metal concentrates.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":"175 1","pages":"Article 104148"},"PeriodicalIF":2.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0923250823001237/pdfft?md5=90b029c273a50b5d2921ff92c90ab130&pid=1-s2.0-S0923250823001237-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41183487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}