Article
Energy & Fuels
Juanjuan Ma, Shuyan Li, Jinxi Wang, Shuting Jiang, Balaji Panchal, Yuzhuang Sun
Summary: This study optimized the culture conditions and bioleaching process of Aspergillus niger for the extraction of rare earth elements (REEs) from coal fly ash (CFA). It was found that organic nitrogen sources influenced the morphology and acid production capacity of A. niger, with oxalic acid being the main acid secreted (4.05 mg/L). The initial pH value was identified as the most influential factor affecting the bioleaching process, and by optimizing it, a leaching rate of 30.91% for total REEs in CFA was achieved. The main mechanism of REEs bioleaching by A. niger from CFA was speculated to be proton exchange and organic ligand complexation.
Article
Engineering, Chemical
Laura Castro, Helena Gomez-Alvarez, Felisa Gonzalez, Jesus A. Munoz
Summary: Rare earth elements (REE) are vital for high-tech products and their environmentally friendly recycling methods are poorly studied. In this study, Aspergillus niger CECT2807 was used to leach REE from fluorescent phosphor powder in fluorescent tubes. The bioleaching experiments showed significant REE dissolution, with Y, Eu, Ce, Tb, and La concentrations reaching 122 mg/l, 8.50 mg/l, 0.95 mg/l, 0.40 mg/l, and 1.11 mg/l, respectively, after 7 days. The residues were analyzed using SEM and XRD, confirming the biotransformation of lamp powder. Semicontinuous experiments further demonstrated increased REE dissolution rate under static conditions, with extraction of 16.5 mg of Y and 0.75 mg of Eu per gram of fluorescent lamp powder.
MINERALS ENGINEERING
(2023)
Article
Biotechnology & Applied Microbiology
Xia Kang, Laszlo Csetenyi, Xiang Gao, Geoffrey Michael Gadd
Summary: In this research, the solubilization of natural struvite by Aspergillus niger and its ability to recover cerium were investigated. The study found that after two weeks of fungal growth, struvite was completely solubilized and released inorganic phosphate through the production of oxalic acid. Various analyses confirmed the formation of cerium minerals, which led to the removal of over 99% of cerium from the solution. Thermal decomposition experiments showed that the biogenic cerium phosphates could be transformed into a mixture of cerium phosphate and cerianite after heat treatment. These findings highlight the potential of using struvite leachate for the biotransformation of soluble rare earth elements and the recovery of cerium for various applications.
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
(2022)
Review
Engineering, Environmental
Emmanuel Yaw Owusu-Fordjour, Xinbo Yang
Summary: Bioleaching, using microorganisms to dissolve minerals and extract Rare Earth Elements (REEs) in aqueous media, has gained attention for its potential eco-friendliness compared to other extraction methods. Mixed culture bioleaching is preferred for efficient REEs extraction, promoting closed-loop recycling and reducing supply chain issues. This literature review provides an overview of challenges, opportunities, microorganisms, mechanisms, approaches, parameters, and techno-economic considerations related to REEs bioleaching, and offers recommendations for future advancements.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Environmental Sciences
Kyriaki Kiskira, Theopisti Lymperopoulou, Ioannis Lourentzatos, Lamprini-Areti Tsakanika, Charalampos Pavlopoulos, Konstantina Papadopoulou, Klaus-Michael Ochsenkuhn, Fotios Tsopelas, Elias Chatzitheodoridis, Gerasimos Lyberatos, Maria Ochsenkuhn-Petropoulou
Summary: Bauxite residue (BR) is a hazardous waste with significant amounts of valuable metals such as scandium. The recovery of scandium from BR using environmentally friendly biometallurgical methods can be an excellent approach for waste management and resource efficiency. In this study, bioleaching of scandium from BR using the fungus Aspergillus niger was investigated. The highest Sc recovery of 46% was achieved in 20 days at 1% pulp density, and biosorption phenomena were observed during the leaching process.
WASTE AND BIOMASS VALORIZATION
(2023)
Review
Biochemistry & Molecular Biology
Laura Castro, Maria Luisa Blazquez, Felisa Gonzalez, Jesus angel Munoz
Summary: Biohydrometallurgy, a method of recovering metals through microbially mediated processes, has gained attention for extracting critical resources such as rare earth elements. The interest in rare earth elements is growing due to their applications in novel technologies and green economy, with biohydrometallurgy being used to extract resources from waste streams to support innovative mining and promote a circular economy.
Article
Biochemistry & Molecular Biology
Fariba Hosseinzadeh, Seyed Omid Rastegar, Morahem Ashengroph
Summary: The study focused on the extraction of rare metals from spent automobile catalyst using Aspergillus niger. Different factors affecting the growth of A. niger were investigated, and high extraction efficiencies were achieved under specific conditions. After bioleaching, the spent residue was treated with aqua regia for platinum and palladium recovery, with 100% recovery rate. Characterization methods such as SEM, FTIR, HPLC, and XRD were used before and after bioleaching.
PROCESS BIOCHEMISTRY
(2021)
Article
Metallurgy & Metallurgical Engineering
Sabrina Hedrich, Anja Breuker, Mirko Martin, Axel Schippers
Summary: Sands from the German Baltic Sea coast are recovered as construction material and contain heavy minerals enriched with zircon, garnet, ilmenite, rutile, magnetite, and monazite. Gravity and magnetic separation can be used to concentrate the heavy minerals. Bioleaching experiments were conducted on zircon concentrates and eudialyte concentrates containing rare earth elements (REE), but the results showed limitations in the extraction of REEs from heavy minerals through bioleaching.
Article
Metallurgy & Metallurgical Engineering
Binyuan Gao, Min Gan, Chongran Sun, Hui Chen, Xi Liu, Qianzi Liu, Yuguang Wang, Haina Cheng, Hongbo Zhou, Zhu Chen
Summary: A cell-free cascade enzymatic process was developed to produce gluconate from low-cost rice straw as an alternative to ammonium sulfate for leaching ion-adsorption rare earth ores. Compared to fermentation, the enzymatic process showed higher yield and superior leaching efficiency. This study provides a new avenue for potentially economical production of biogenic lixiviants from renewable and cheap feedstocks.
Article
Metallurgy & Metallurgical Engineering
Laura Castro, Helena Gomez-Alvarez, Manuel Carmona, Felisa Gonzalez, Jesus A. Munoz
Summary: The aim of this study was to investigate the solubilization of monazite and recovery of REE using Burkholderia thailandensis, and the influence of the rhamnolipids produced by the bacteria on REE mobilization. B. thailandensis grown in nutrient broth with 1% monazite (w/v) achieved a REE concentration of 8.3 mg center dot l-1 after 15 days. Rhamnolipids were produced by B. thailandensis grown in medium supplemented with 10% glycerol, and the critical micelle concentration (CMC) was determined to be 94.45 mg center dot l-1 for commercial rhamnolipids and 60.41 mg center dot l-1 for purified rhamnolipids. The maximum REE solubilization was achieved at CMC, with 9.36 mg center dot l-1 for commercial rhamnolipids and 5.13 mg center dot l-1 for rhamnolipids produced by B. thailandensis E264.
Article
Biotechnology & Applied Microbiology
Y. Tian, X. Hu, X. Song, A. J. Yang
Summary: This study investigates the bioleaching of rare-earth elements (REEs) from phosphate rock using Acidithiobacillus ferrooxidans for the first time, and it shows that the bioleaching process is more efficient and environmentally friendly compared to abiotic leaching. The results also suggest that bacterial contact and Fe2+ oxidation play a key role in the bioleaching process, and extracellular polymeric substances contribute to the leaching of REEs.
LETTERS IN APPLIED MICROBIOLOGY
(2022)
Article
Engineering, Environmental
Hao Zhou, Xinyi Yu, Junjun Wang, Guanzhou Qiu, Hongbo Zhao, Li Shen
Summary: This study investigated the non-contact bioleaching of REEs using Aspergillus niger strain and explored the optimal culture and leaching conditions. Metabolomic analysis revealed the differential metabolites produced by the strain before and after leaching, highlighting the important roles of organic acids and their derivatives in the process.
CHEMICAL ENGINEERING JOURNAL
(2023)
Review
Engineering, Environmental
Sandeep Panda, Rachel Biancalana Costa, Syed Sikandar Shah, Srabani Mishra, Denise Bevilaqua, Ata Akcil
Summary: The study highlights the potential of unexploited bauxite residues as a rich source of REEs, which could unlock approximately a 4.3 trillion-dollar economy globally. Despite environmental concerns and disposal challenges, bio-technological recovery of REEs from bauxite residues could be a promising alternative.
RESOURCES CONSERVATION AND RECYCLING
(2021)
Article
Engineering, Environmental
Xiaoyu Meng, Hongbo Zhao, Yu Zhao, Li Shen, Guohua Gu, Guanzhou Qiu
Summary: A new three-step precipitation process is proposed to efficiently recover rare earth-citrate (RE-Cit) complexes from (bio)leaching lixivium. This technology shows promise in the industrial application of rare earth (bio) hydrometallurgy and wastewater treatment due to its advantages of high efficiency, low cost, environmental friendliness, and simple operation.
Article
Engineering, Environmental
Shuronjit Kumar Sarker, Warren Bruckard, Nawshad Haque, Rajeev Roychand, Muhammed Bhuiyan, Biplob Kumar Pramanik
Summary: The depletion of high-grade deposits of rare earth elements (REEs) has led to an increased interest in reprocessing mining tailings, particularly from carbonatite-related deposits, which is where most of the world's REEs are produced. This study aimed to characterize the potential for REE recovery in a carbonatite-related tailing from an Australian mine. The tailing sample was analyzed using various methods, and it was found that the tailing consisted of mainly fine particles with a high concentration of iron and REEs. The main REE-bearing minerals were identified, and it was suggested that grinding the larger particle fractions and subsequent separation processes could potentially recover the locked REE-minerals.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Metallurgy & Metallurgical Engineering
Ernesto Gonzalez, Loreto Hernandez, Jesus Angel Munoz, Maria Luisa Blazquez, Antonio Ballester, Felisa Gonzalez
Article
Metallurgy & Metallurgical Engineering
Laura Castro, Jing Li, Felisa Gonzalez, Jesus A. Munoz, M. Luisa Blazquez
Article
Materials Science, Multidisciplinary
Anna Khachatryan, Narine Vardanyan, Arevik Vardanyan, Ruiyong Zhang, Laura Castro
Summary: This study investigated the bioleaching potential of a newly isolated strain Leptospirillum (L.) ferriphilum CC for pyrite and chalcopyrite, showing promising kinetic performance in Fe2+ oxidation and competitive inhibition by Fe3+. The strain also exhibited high potential for biogenic regeneration of concentrated ferric iron (Fe3+) in bioleaching processes, indicating it as a prospective candidate for sulfide mineral bioleaching.
Article
Geochemistry & Geophysics
Laura Castro, Fabiana Rocha, Jesus Angel Munoz, Felisa Gonzalez, Maria Luisa Blazquez
Summary: Iron nanoparticles produced by a microbial consortium showed promising adsorption capabilities for metal removal from electroplating industry wastewaters. Optimization of fixed-bed columns can be achieved to enhance adsorption performance, with the up-flow system significantly improving metal uptake efficiency.
Review
Biochemistry & Molecular Biology
Laura Castro, Maria Luisa Blazquez, Felisa Gonzalez, Jesus angel Munoz
Summary: Biohydrometallurgy, a method of recovering metals through microbially mediated processes, has gained attention for extracting critical resources such as rare earth elements. The interest in rare earth elements is growing due to their applications in novel technologies and green economy, with biohydrometallurgy being used to extract resources from waste streams to support innovative mining and promote a circular economy.
Article
Materials Science, Multidisciplinary
Laura Castro, Lesly Antonieta Ayala, Arevik Vardanyan, Ruiyong Zhang, Jesus Angel Munoz
Summary: Arsenic pollution in waters is caused by both natural and human sources. This study demonstrates the potential of biogenic iron compounds produced by anaerobic microorganisms for efficient removal of harmful metals. The use of biogenic precipitates as adsorbents in contact with arsenic solutions shows promise for water treatment applications, especially in areas with high concentrations of arsenic.
Editorial Material
Materials Science, Multidisciplinary
Laura Castro, Maria Luisa Blazquez, Jesus Angel Munoz
Article
Microbiology
Maria Castillo Lopez, Beatriz Galan, Manuel Carmona, Juana Maria Navarro Llorens, Juli Pereto, Manuel Porcar, Luis Getino, Elias R. Olivera, Jose M. Luengo, Laura Castro, Jose Luis Garcia
Summary: The highly xerotolerant bacterium Exiguobacterium sp. Helios isolated from a solar panel in Spain shows close relationship to Exiguobacterium sibiricum 255-15 from Siberian permafrost. Both strains demonstrate higher xerotolerance than the model strain Deinococcus radiodurans, with significant changes observed in cell morphology after desiccation. Apart from remarkable desiccation resistance, strain Helios also produces selenium nanoparticles and has been genetically modified, making it a promising candidate for biotechnological applications.
Article
Microbiology
Gabriel Hernandez-Fernandez, Beatriz Galan, Manuel Carmona, Laura Castro, Jose Luis Garcia
Summary: A new bacterial strain, Arthrobacter sp. Helios, isolated from solar panels, shows high tolerance to desiccation, UV radiation, metals, and metalloids. It is motile and adaptable to a variety of carbon sources, making it a potential biotechnological chassis. Genomic sequencing reveals its well-poised response to environmental stresses. Transcriptional analysis identifies genes involved in cellular homeostasis, ion and osmolyte transport, iron scavenging, and biogenic amine catabolism, suggesting their roles in the desiccation resistance mechanism.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Biotechnology & Applied Microbiology
Elena Alonso-Fernandes, Helga Fernandez-Llamosas, Irene Cano, Cristina Serrano-Pelejero, Laura Castro, Eduardo Diaz, Manuel Carmona
Summary: Pollution by metalloids, such as tellurite and selenite, is a serious environmental concern. This study focuses on the use of Aromatoleum sp. CIB as a platform for tellurite elimination. The CIB strain is able to tolerate and reduce tellurite into rod-shaped tellurium nanoparticles. The overexpression of a methyltransferase gene enhances the removal of tellurite and selenite and promotes the production of tellurium and selenium nanoparticles.
MICROBIAL BIOTECHNOLOGY
(2023)
Article
Geochemistry & Geophysics
Arevik Vardanyan, Anna Khachatryan, Laura Castro, Sabine Willscher, Stoyan Gaydardzhiev, Ruiyong Zhang, Narine Vardanyan
Summary: A strain of Leptospirillum sp. CC isolated from Akhtala polymetallic ore in Armenia exhibited optimal growth at a temperature of 40 degrees C and at a pH of 1.5. Phylogenetic analysis revealed its close relationship with L. ferriphilum and a high sequence similarity with strain L. ferriphilum OL12-2. The isolate displayed efficient oxidation of Fe(II) and demonstrated increased pyrite oxidation activity when co-cultivated with At. ferrooxidans ZnC. Furthermore, the association of L.ferriphilum CC with heterotrophic Acidocella sp. RBA bacteria showed the highest activity in pyrite oxidation.
Article
Metallurgy & Metallurgical Engineering
Laura Castro, Helena Gomez-Alvarez, Manuel Carmona, Felisa Gonzalez, Jesus A. Munoz
Summary: The aim of this study was to investigate the solubilization of monazite and recovery of REE using Burkholderia thailandensis, and the influence of the rhamnolipids produced by the bacteria on REE mobilization. B. thailandensis grown in nutrient broth with 1% monazite (w/v) achieved a REE concentration of 8.3 mg center dot l-1 after 15 days. Rhamnolipids were produced by B. thailandensis grown in medium supplemented with 10% glycerol, and the critical micelle concentration (CMC) was determined to be 94.45 mg center dot l-1 for commercial rhamnolipids and 60.41 mg center dot l-1 for purified rhamnolipids. The maximum REE solubilization was achieved at CMC, with 9.36 mg center dot l-1 for commercial rhamnolipids and 5.13 mg center dot l-1 for rhamnolipids produced by B. thailandensis E264.
Article
Engineering, Chemical
Laura Castro, Helena Gomez-Alvarez, Felisa Gonzalez, Jesus A. Munoz
Summary: Rare earth elements (REE) are vital for high-tech products and their environmentally friendly recycling methods are poorly studied. In this study, Aspergillus niger CECT2807 was used to leach REE from fluorescent phosphor powder in fluorescent tubes. The bioleaching experiments showed significant REE dissolution, with Y, Eu, Ce, Tb, and La concentrations reaching 122 mg/l, 8.50 mg/l, 0.95 mg/l, 0.40 mg/l, and 1.11 mg/l, respectively, after 7 days. The residues were analyzed using SEM and XRD, confirming the biotransformation of lamp powder. Semicontinuous experiments further demonstrated increased REE dissolution rate under static conditions, with extraction of 16.5 mg of Y and 0.75 mg of Eu per gram of fluorescent lamp powder.
MINERALS ENGINEERING
(2023)