In the commercial BIOX® process, an acidophilic mixed bacterial and archaeal community dominated by iron and sulphur oxidising microorganisms is used to facilitate the recovery of precious metals from refractory gold-bearing sulphidic mineral concentrates. Characterisation of the microbial communities associated with commercial BIOX® reactors from four continents revealed a significant shift in the microbial community structure compared to that of the seed culture, maintained at SGS (South Africa). This has motivated more detailed study of the microbial community dynamics in the process. Microbial speciation of a subset of the BIOX® reactors at Fairview mines (Barberton, South Africa) and two laboratory maintained reactors housed at Centre for Bioprocess Engineering Research, University of Cape Town, has been performed tri-annually for three years by quantitative real-time polymerase chain reaction. The laboratory BIOX® culture maintained on Fairview concentrate was dominated by the desired iron oxidiser, Leptospirillum ferriphilum, and sulphur oxidiser, Acidithiobacillus caldus, when operated under standard BIOX® conditions. Shifts in the microbial community as a result of altered operating conditions were transient and did not result in a loss of the microbial diversity of the BIOX® culture. The community structure of the Fairview mines BIOX® reactor tanks showed archaeal dominance of these communities by organisms such as the iron oxidiser Ferroplasma acidiphilum and a Thermoplasma sp. for the period monitored. Shifts in the microbial community were observed across the monitoring period and mapped to changes in performance of the commercial process plant. Understanding the effect of changes in the plant operating conditions on the BIOX® community structure may assist in providing conditions that support the desired microbial consortium for optimal biooxidation to maximize gold recovery.
Aim:To examine the effects of water treatment methods on the protein profile of Escherichia coli O157 and Escherichia coli non-O157 isolated from different drinking water sources in Ado-Ekiti. Study Design: Experimental study design. Place and Duration of Study: Methodology: The test organisms, E. coli O157 and E. coli non-O157, were charged against some water treatment methods such as silver nitrate, sunlight, low and high temperature and varied pH Olowe et al.; MRJI, 20(5): 1-10, 2017; Article no.MRJI.33638 2 using standard methods. Protein expression profiles of these organisms, before and after exposure, were studied with cell crude proteins extract using standard SDS-PAGE method. Statistical analysis was carried out on the data generated using correlation matrix. Results: The survivability testing showed that E. coli O157 survived better than E. coli non-O157. Silver nitrate, among all other agents used, exhibited the most lethal effect on both serotypes. The protein profile of the two serotypes was similar before their exposure (r = 0.9897, P-value = 0.941), while after their exposure, they exhibited different characteristic responses (r = 0.693, P-value = 0.018). Conclusion: This study showed that the treatment methods had effects on the expression of bacterial protein profile following exposure.
Original Research Article
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.