Key Laboratory of Biometallurgy of Ministry of Education

Hunan, China

Key Laboratory of Biometallurgy of Ministry of Education

Hunan, China
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Li Q.,Central South University | Tian Y.,Central South University | Tian Y.,Key Laboratory of Biometallurgy of Ministry of Education | Fu X.,Central South University | And 19 more authors.
Current Microbiology | Year: 2011

To determine the effect of organics (yeast extract) on microbial community during chalcopyrite bioleaching at different temperature, real-time polymerase chain reaction (PCR) was employed to analyze community dynamics of major bacteria applied in bioleaching. The results showed that yeast extract exerted great impact on microbial community, and therefore influencing bioleaching rate. To be specific, yeast extract was adverse to this bioleaching process at 30°C due to decreased proportion of important chemolithotrophs such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. However, yeast extract could promote bioleaching rate at 40°C on account of the increased number and enhanced work of Ferroplasma thermophilum, a kind of facultative bacteria. Similarly, bioleaching rate was enhanced under the effect of yeast extract at 50°C owing to the work of Acidianus brierleyi. At 60°C, bioleaching rate was close to 100% and temperature was the dominant factor determining bioleaching rate. Interestingly, the existence of yeast extract greatly enhanced the relative competitiveness of Ferroplasma thermophilum in this complex bioleaching microbial community. © Springer Science+Business Media, LLC 2011.

Fang Y.,Guangdong Institute of Microbiology | Fang Y.,Central South University | Fang Y.,Key Laboratory of Biometallurgy of Ministry of Education | Fang Y.,State Key Laboratory of Applied Microbiology Ministry Guangdong Province Jointly Breeding Base | And 11 more authors.
Frontiers of Environmental Science and Engineering | Year: 2015

Extraction of high-quality microbial DNA from contaminated environmental samples is an essential step in microbial ecological study. Based on previously published methods for soil and sediment samples, a modified pretreatment method was developed for extracting microbial DNA from heavily contaminated river sediment samples via selection of optimal pretreatment parameters (i.e., reagent solution, reaction duration, and temperature). The pretreatment procedure involves washing the river sediment sample for three times with a solution containing 0.1 mol·L−1 ethylene diamine tetraacetic acid (EDTA), 0.1 mol·L−1 Tris (pH 8.0), 1.5 mol·L−1 NaCl, 0.1 mol·L−1 NaH2PO4, and Na2HPO4 at 65°C with 180 r·min−1 for 15 min to remove humic materials and heavy metals prior to the employment of standard DNA extraction procedures. We compared the results of standard procedure DNA extraction following pretreatment, without pretreatment, and with using a commercial PowerSoil™ DNA Isolation Kit. The results indicated that the pretreatment significantly improved the DNA quality based on DNA yield, DNA fragment length, and determination of prokaryotic diversity. Prokaryotic diversity exhibited in the DNA with the pretreatment was also considerably higher than that extracted with the PowerSoil™ DNA Isolation Kit only. The pretreatment method worked well even with a small amount of sediment sample (0.25 g or even lower). The method provides a novel, simple, cost-effective tool for DNA extraction for microbial community analysis in environmental monitoring and remediation processes. © 2014, Higher Education Press and Springer-Verlag Berlin Heidelberg.

Zhu J.,Central South University | Zhu J.,Key Laboratory of Biometallurgy of Ministry of Education | Li Q.,Central South University | Jiao W.,Central South University | And 15 more authors.
Colloids and Surfaces B: Biointerfaces | Year: 2012

The efficiency of copper leaching is improved by bacteria attached to chalcopyrite. Therefore, the study of the attachment mechanism to control leaching is important. The adhesion of three species of leaching microorganisms including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans to chalcopyrite was investigated by using atomic force microscopy (AFM). The forces were measured with tip-immobilized cells approached to and retracted from the mineral. The results show that both the surface charge and the hydrophobicity of bacteria cells influence the adhesion force. Furthermore, the adhesion force decreased in case the extracellular polymeric substances (EPS) had been removed. In addition, the data indicate that the amount of attached cells increased with increasing adhesion force. © 2012 Elsevier B.V.

Yin H.,Central South University | Yin H.,Key Laboratory of Biometallurgy of Ministry of Education | Tang M.,Central South University | Tang M.,Key Laboratory of Biometallurgy of Ministry of Education | And 14 more authors.
Canadian Journal of Microbiology | Year: 2012

Temperature plays an important role in the heap bioleaching. The maldistribution of ventilation in the heap leads to local hyperthermia, which does exert a tremendous stress on bioleaching microbes. In this study, the genome-wide expression profiles of Acidithiobacillus ferrooxidans at 40°C were detected using the microarray. The results showed that some classic proteases like Lon and small heat-shock proteins were not induced, and heat-inducible membrane proteins were suggested to be under the control of σE. Moreover, expression changes of energy metabolism are noteworthy, which is different from that in heterotrophic bacteria upon heat stress. The induced enzymes catalyzed the central carbon metabolism pathway that might mainly provide precursors of amino acids for protein synthesis. These results will deepen the understanding of the mechanisms of heat-shock response on autotrophic bacteria.

Hu Q.,Central South University | Hu Q.,Key Laboratory of Biometallurgy of Ministry of Education | Liang Y.L.,Central South University | Liang Y.L.,Key Laboratory of Biometallurgy of Ministry of Education | And 10 more authors.
Advanced Materials Research | Year: 2013

The leaching heap and acid mine drainage are two key nodes in a bioleaching system. This study aimed to investigate the microbial community structural and functional diversity between the two nodes in bioleaching system from Dexing copper mine in Jiangxi province, China. 16SrRNA gene cloning and metagenomic analysis consistently indicated that there were obvious differences on microbial community structural and functional diversity in the two nodes. In leaching heap, the dominant species was the heterotrophic bacterium Acidiphilium; while the dominant species was the autotrophic bacterium Acidithiobacillus in acid mine drainage. Seven bacteria species were found in both two nodes, while the unique bacteria species in leaching heap and acid mine drainage were eleven and eight, respectively. In relation to the microbial community function aspect, all contigs and singlets were annotated against the non-redundant protein database of NCBI and clustering analyzed with COG database. For the two nodes, the COG clustering results showed that the functional category abundances were different, though the functional categories were similar. And the great majority of ORFs were forecasted as function unknown. All the results meant that the microbial community structural and functional diversity of bioleaching system was not as simple as former thought. This study could provide a new meta-view of theoretical support to bioleaching process. © (2013) Trans Tech Publications, Switzerland.

Gan M.,Central South University | Gan M.,Key Laboratory of Biometallurgy of Ministry of Education | Song Z.,Central South University | Song Z.,Key Laboratory of Biometallurgy of Ministry of Education | And 4 more authors.
Environmental Earth Sciences | Year: 2016

Heavy metal contamination has become a world concern with the rapid industrialization and urbanization process. In this study, a mesophile consortium including Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans and Leptospirillum ferriphilum was applied in metals’ bioleaching with the assistance of isolated acid-tolerant microorganisms Rhodotorula and Aspergillus niger. The results showed that the bioleaching was totally inhibited in non-batch method system for the alkalinity and buffering capacity of the sediment. The inhibition on bioleaching can be effectively relieved with the batch method adopted. Dissolved organic matter hampered the substrate utilization and prolonged the bioleaching process. The toxic effect of dissolved organic matter to acidophile can be reduced by the isolated heterotrophic microorganism. A. thiooxidans was the dominant species in the early bioleaching stage, while the ratio of ferrous oxidation bacteria increased in the later stage. The introduction of heterotrophic microorganism to the system contributed to form a suitable ecological niche of each species. In the batch method adopted and heterotrophic microorganism inoculated system, the bioleaching efficiency of Mn, Cu, Zn and Cd reached 94, 90.9, 94.74 and 84.2 %, respectively. The main fractions of heavy metals after bioleaching are comparatively stable speciation. Heavy metals were reduced both in total content and bioavailability. © 2016, Springer-Verlag Berlin Heidelberg.

Zhou Z.,Central South University | Zhou Z.,Key Laboratory of Biometallurgy of Ministry of Education | Fang Y.,Central South University | Fang Y.,Key Laboratory of Biometallurgy of Ministry of Education | And 14 more authors.
World Journal of Microbiology and Biotechnology | Year: 2012

Acidithiobacillus ferrooxidans (A. ferrooxidans) ATCC 23270 is a model bacteria for bioleaching research. Because of the use of extractant in metal extraction industry, A. ferrooxidans needs to cope with the water-organic two-phase system. To get insight into the molecular response of A. ferrooxidans to organic solvent, global gene expression pattern was examined in A. ferrooxidans ATCC 23270 cells subjected to Lix984n (an organic extractant) using the method of whole-genome DNA microarray. The data suggested that the global response of A. ferrooxidans to Lix984n stress was characterized by the up-regulation of genes involved in pentose phosphate pathway, fatty acid and glutamate biosynthesis. In further study, compared to heterotrophic bacteria in dealing with short-time stress, A. ferrooxidans has a special strategy of continuously enhancing the expression of genes encoding proteins involved in electron transport, such as petI, petII, cyo and cyd. Besides, acrAB-tolC operon encoding organic solvent efflux pump and its positive regulator gene ostR were addressed. © 2011 Springer Science+Business Media B.V.

Gan M.,Central South University | Gan M.,Key Laboratory of Biometallurgy of Ministry of Education | Zhou S.,Central South University | Zhou S.,Key Laboratory of Biometallurgy of Ministry of Education | And 8 more authors.
Environmental Science and Pollution Research | Year: 2015

A defined mesophile consortium including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirilum ferriphilum was applied in bioleaching sediments contaminated with multiple heavy metals. Flask experiments showed that sulfur favored the acidification in the early stage while pyrite led to a great acidification potential in the later stage. An equal sulfur/pyrite ratio got the best acidification effect. Substrate utilization started with sulfur in the early stage, and then the pH decline and the community shift give rise to the utilization of pyrite. Solubilization efficiency of Zn, Cu, Mn, and Cd reached 96.1, 93.3, 92.13, and 87.65 %, respectively. Bioleaching efficiency of other elements (As, Hg, Pb) was not more than 30 %. Heavy metal solubilization was highly negatively correlated with pH variation. Logistic models were well fitted with the solubilization efficiency, which can be used to predict the bioleaching process. The dominant species in the early stage of bioleaching were A. ferrooxidans and A. thiooxidans, and the abundance of L. ferriphilum increased together with pyrite utilization and pH decline. © 2014, Springer-Verlag Berlin Heidelberg.

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