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Arias D, Saldaña M, Botero YL, Dinamarca F, Paredes B, Salazar-Ardiles C, Andrade DC, Cisternas LA, Carrasco J, Santos C, Dorador C, Gómez-Silva B. Exploring the potential of the halotolerant bacterial strain Bacillus subtilis LN8B as an ecofriendly sulfide collector for seawater flotation. J Appl Microbiol 2024; 135:lxad313. [PMID: 38126104 DOI: 10.1093/jambio/lxad313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 12/23/2023]
Abstract
AIM To assess the effectiveness of Bacillus subtilis strain LN8B as a biocollector for recovering pyrite (Py) and chalcopyrite (CPy) in both seawater (Sw) and deionized water (Dw), and to explore the underlying adhesion mechanism in these bioflotation experiments. MATERIALS AND METHODS The bioflotation test utilized B. subtilis strain LN8B as the biocollector through microflotation experiments. Additionally, frother methyl isobutyl carbinol (MIBC) and conventional collector potassium amyl xanthate (PAX) were introduced in some experiments. The zeta potential (ZP) and Fourier-transform infrared spectroscopy (FTIR) was employed to explore the adhesion mechanism of Py and CPy interacting with the biocollector in Sw and Dw. The adaptability of the B. subtilis strain to different water types and salinities was assessed through growth curves measuring optical density. Finally, antibiotic susceptibility tests were conducted to evaluate potential risks of the biocollector. RESULTS Superior outcomes were observed in Sw where Py and CPy recovery was ∼39.3% ± 7.7% and 41.1% ± 5.8%, respectively, without microorganisms' presence. However, B. subtilis LN8B potentiate Py and CPy recovery, reaching 72.8% ± 4.9% and 84.6% ± 1.5%, respectively. When MIBC was added, only the Py recovery was improved (89.4% ± 3.6%), depicting an adverse effect for CPy (81.8% ± 1.1%). ZP measurements indicated increased mineral surface hydrophobicity when Py and CPy interacted with the biocollector in both Sw and Dw. FTIR revealed the presence of protein-related amide peaks, highlighting the hydrophobic nature of the bacterium. The adaptability of this strain to diverse water types and salinities was assessed, demonstrating remarkable growth versatility. Antibiotic susceptibility tests indicated that B. subtilis LN8B was susceptible to 23 of the 25 antibiotics examined, suggesting it poses minimal environmental risks. CONCLUSIONS The study substantiates the biotechnological promise of B. subtilis strain LN8B as an efficient sulfide collector for promoting cleaner mineral production. This effectiveness is attributed to its ability to induce mineral surface hydrophobicity, a result of the distinct characteristics of proteins within its cell wall.
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Affiliation(s)
- Dayana Arias
- Laboratory of Molecular Biology and Applied Microbiology, Research Center in High Altitude Medicine and Physiology, Biomedical Department, Faculty of Health Science, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Manuel Saldaña
- Faculty of Engineering and Architecture, Arturo Prat University, Iquique 1110939, Chile
| | - Yesica L Botero
- Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Francisco Dinamarca
- Biochemistry Lab., Biomedical Dept., Health Sciences Faculty and Centre for Biotechnology and Bioengineering (CeBiB), Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Bernardo Paredes
- Biochemistry Lab., Biomedical Dept., Health Sciences Faculty and Centre for Biotechnology and Bioengineering (CeBiB), Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Camila Salazar-Ardiles
- Laboratory of Molecular Biology and Applied Microbiology, Research Center in High Altitude Medicine and Physiology, Biomedical Department, Faculty of Health Science, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - David C Andrade
- Exercise Applied Physiology Laboratory, Research Center in High Altitude Medicine and Physiology, Biomedical Department, Faculty of Health Science, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Luis A Cisternas
- Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Jorge Carrasco
- Departamento de Ingeniería en Minas, Facultad de Ingeniería, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Carlos Santos
- Departamento de Ingeniería en Minas, Facultad de Ingeniería, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Cristina Dorador
- Department of Biotechnology, Faculty of Marine Sciences and Biological Resources and Centre for Biotechnology and Bioengineering (CeBiB), Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
| | - Benito Gómez-Silva
- Biochemistry Lab., Biomedical Dept., Health Sciences Faculty and Centre for Biotechnology and Bioengineering (CeBiB), Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1270300, Chile
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Bomberg M, Miettinen H. Anionic nanocellulose as competing agent in microbial DNA extraction from mine process samples. J Microbiol Methods 2023; 215:106850. [PMID: 37907119 DOI: 10.1016/j.mimet.2023.106850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 09/04/2023] [Accepted: 10/25/2023] [Indexed: 11/02/2023]
Abstract
Microorganisms in flotation and minerals processing may significantly affect the grade and yield of metal concentrates. However, studying the phenomena requires working techniques to detach microorganisms and their DNA from mineral particles to which they strongly adhere. We developed a new method utilizing the competitive properties of anionic nanocellulose to block sorption of DNA to and detach microbial cells from mineral particles from ore processing. In general, up to one ng DNA mL-1 sample was obtained with the custom anionic nanocellulose method (CM) compared to DNA amounts below the Qubit assay's detection limit for extractions with a commercial kit (KIT). Similarly, 0.5-4 orders of magnitude more bacterial 16S and fungal 5.8S rRNA gene copies were detected by qPCR from CM treated samples compared to KIT extractions. A clear difference in the detected microbial community structure between CM and KIT extracted samples was also observed. Commercial kits optimized for mineral soils are easy to use and time efficient but may miss a considerable part of the microbial communities. A competing agent such as anionic nanocellulose may decrease the interaction between microorganisms or their DNA and minerals and provide a comprehensive view into the microbial communities in mineral processing environments.
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Affiliation(s)
- Malin Bomberg
- VTT Technical Research Centre of Finland, P.O. Box 1000, 02044 VTT, Finland.
| | - Hanna Miettinen
- VTT Technical Research Centre of Finland, P.O. Box 1000, 02044 VTT, Finland
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