Multi-Objective Optimization of Copper Bioleaching: Comparative Study of Pure and Co-Cultured Cultivation

Iranian Journal of Biotechnology

article

Rakhshani, Yasin¹  Rahpeyma, Sayyed Shahryar¹  Tabandeh, Fatemeh⁴  Arabnezhad, Mahmood⁵  Azimi, Ali⁵  Raheb, Jamshid¹ 

[1] Department of Molecular Medicine, Institute of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology;Department of Microbiology, Karaj Branch, Islamic Azad University;Department of Systems Biotechnology, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology;Department of Energy and Environmental Biotechnology, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology;National Iranian Copper Industries Corporation

关键词: Acidithiobacillus ferrooxidans;    Acidithiobacillus thiooxidans;    Bioleaching;    Optimization;    Percolation column;    Response surface methodology;   

DOI  :  10.30498/ijb.2023.328969.3278

学科分类：生物技术

来源: National Institute for Genetic Engineering and Biotechnology

【 摘 要 】

Background: Bioleaching is a practical method to recover metals from low-grade mineral sulfides. The most frequent bacteria involved in the bioleaching of metals from ores are Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. Experimental design is a method through which the optimum activity condition will be obtained, avoiding numerous trials and errors. Objectives: This study aimed to optimize the bioleaching condition of two indigenous iron- and sulfur-oxidizing bacteria from the Meydouk mine, Iran, and evaluate their function in a semi-pilot operation in pure and mixed cultures. Material and Methods: After treatment with sulfuric acid, the bacterial DNA was extracted, and further 16S rRNA was sequenced to characterize the bacterial species. The cultivation condition of these bacteria was optimized using Designexpert (6.1.1 version) software. The copper recovery rate and the differentiation in the ORP rate in the percolation columns were also investigated. These strains were isolated from the Meydouk mine for the first time. Results: 16S rRNA analysis revealed that both bacteria belong to the Acidithiobacillus genus. The factors with the most significant impact on Acidithiobacillus ferrooxidans with their optimum level were temperature=35 °C, pH=2.5, and initial FeSO4 concentration=25 g.L-1. Also, initial sulfur concentration had the most significant impact on Acidithiobacillus thiooxidans with the optimum level of 35 g.L-1. Moreover, the mixed culture determined higher bioleaching efficiency compared with the case of employing the pure cultures. Conclusions: Utilizing a mixture of both bacteria, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans elevated the Cu recovery rate due to the synergetic function of the strains. Also, introducing an initial dosage of sulfur and pre-acidification could elevate metal recovery efficiency.

【 授权许可】

Unknown