Bioleaching of electronic waste using bacteria isolated from the marine sponge Hymeniacidon heliophila (Porifera).

Science.gov (United States)

Rozas, Enrique E; Mendes, Maria A; Nascimento, Claudio A O; Espinosa, Denise C R; Oliveira, Renato; Oliveira, Guilherme; Custodio, Marcio R

2017-05-05

The bacteria isolated from Hymeniacidon heliophila sponge cells showed bioleaching activity. The most active strain, Hyhel-1, identified as Bacillus sp., was selected for bioleaching tests under two different temperatures, 30°C and 40°C, showing rod-shaped cells and filamentous growth, respectively. At 30°C, the bacteria secreted substances which linked to the leached copper, and at 40°C metallic nanoparticles were produced inside the cells. In addition, infrared analysis detected COOH groups and linear peptides in the tested bacteria at both temperatures. The Hyhel-1 strain in presence of electronic waste (e-waste) induced the formation of crust, which could be observed due to bacteria growing on the e-waste fragment. SEM-EDS measurements showed that the bacterial net surface was composed mostly of iron (16.1% w/w), while a higher concentration of copper was observed in the supernatant (1.7% w/w) and in the precipitated (49.8% w/w). The substances linked to copper in the supernatant were sequenced by MALDI-TOF-ms/ms and identified as macrocyclic surfactin-like peptides, similar to the basic sequence of Iturin, a lipopeptide from Bacillus subtilis. Finally, the results showed that Hyhel-1 is a bioleaching bacteria and cooper nanoparticles producer and that this bacteria could be used as a copper recovery tool from electronic waste. Copyright © 2017 Elsevier B.V. All rights reserved.

Laboratory assessment of bioleaching of shallow eutrophic sediment by immobilized photosynthetic bacteria.

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Sun, Shiyong; Fan, Shenglan; Shen, Kexuan; Lin, Shen; Nie, Xiaoqin; Liu, Mingxue; Dong, Faqin; Li, Jian

2017-10-01

Eutrophic sediment is a serious problem in ecosystem restoration, especially in shallow lake ecosystems. We present a novel bioleaching approach to treat shallow eutrophic sediment with the objective of preventing the release of nitrate, phosphate, and organic compounds from the sediment to the water column, using porous mineral-immobilized photosynthetic bacteria (PSB). Bioactivity of bacteria was maintained during the immobilization process. Immobilized PSB beads were directly deposited on the sediment surface. The deposited PSB utilized pollutants diffused from the sediment as a nutritive matrix for growth. We evaluated the effects of light condition, temperature, initial pH, amount of PSB beads, and frequency of addition of PSB beads for contaminant removal efficiency during bioleaching operations. The presented study indicated that immobilized PSB beads using porous minerals as substrates have considerable application potential in bioremediation of shallow eutrophic lakes.

Bioleaching of metals from spent refinery petroleum catalyst using moderately thermophilic bacteria: effect of particle size.

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Srichandan, Haragobinda; Singh, Sradhanjali; Pathak, Ashish; Kim, Dong-Jin; Lee, Seoung-Won; Heyes, Graeme

2014-01-01

The present work investigated the leaching potential of moderately thermophilic bacteria in the recovery of metals from spent petroleum catalyst of varying particle sizes. The batch bioleaching experiments were conducted by employing a mixed consortium of moderate thermophilic bacteria at 45°C and by using five different particle sizes (from 45 to >2000 μm) of acetone-washed spent catalyst. The elemental mapping by FESEM confirmed the presence of Al, Ni, V and Mo along with sulfur in the spent catalyst. During bioleaching, Ni (92-97%) and V (81-91%) were leached in higher concentrations, whereas leaching yields of Al (23-38%) were found to be lowest in all particle sizes investigated. Decreasing the particle size from >2000 μm to 45-106 μm caused an increase in leaching yields of metals during initial hours. However, the final metals leaching yields were almost independent of particle sizes of catalyst. Leaching kinetics was observed to follow the diffusion-controlled model showing the linearity more close than the chemical control. The results of the present study suggested that bioleaching using moderate thermophilic bacteria was highly effective in removing the metals from spent catalyst. Moreover, bioleaching can be conducted using spent catalyst of higher particle size (>2000 μm), thus saving the grinding cost and making process attractive for larger scale application.

Extraction of manganese from electrolytic manganese residue by bioleaching.

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Xin, Baoping; Chen, Bing; Duan, Ning; Zhou, Changbo

2011-01-01

Extraction of manganese from electrolytic manganese residues using bioleaching was investigated in this paper. The maximum extraction efficiency of Mn was 93% by sulfur-oxidizing bacteria at 4.0 g/l sulfur after bioleaching of 9days, while the maximum extraction efficiency of Mn was 81% by pyrite-leaching bacteria at 4.0 g/l pyrite. The series bioleaching first by sulfur-oxidizing bacteria and followed by pyrite-leaching bacteria evidently promoted the extraction of manganese, witnessing the maximum extraction efficiency of 98.1%. In the case of sulfur-oxidizing bacteria, the strong dissolution of bio-generated sulfuric acid resulted in extraction of soluble Mn2+, while both the Fe2+ catalyzed reduction of Mn4+ and weak acidic dissolution of Mn2+ accounted for the extraction of manganese with pyrite-leaching bacteria. The chemical simulation of bioleaching process further confirmed that the acid dissolution of Mn2+ and Fe2+ catalyzed reduction of Mn4+ were the bioleaching mechanisms involved for Mn extraction from electrolytic manganese residues. Copyright © 2010 Elsevier Ltd. All rights reserved.

Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect

International Nuclear Information System (INIS)

Mishra, Debaraj; Kim, Dong J.; Ralph, David E.; Ahn, Jong G.; Rhee, Young H.

2008-01-01

Bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. The first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. In the second stage, the acidic medium was utilized for the leaching process. Nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium by the action of sulfuric acid that was produced by acidophilic leaching bacteria. Experiments were conducted varying the reaction time, amount of spent catalysts, amount of elemental sulfur and temperature. At 50 g/L spent catalyst concentration and 20 g/L elemental sulfur, 88.3% Ni, 46.3% Mo, and 94.8% V were recovered after 7 days. Chemical leaching with commercial sulfuric acid of the similar amount that produced by bacteria was compared. Thermodynamic parameters were calculated and the nature of reaction was found to be exothermic. Leaching kinetics of the metals was represented by different reaction kinetic equations, however, only diffusion controlled model showed the best correlation here. During the whole process Mo showed low dissolution because of substantiate precipitation with leach residues as MoO 3 . Bioleach residues were characterized by EDX and XRD

Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect

Energy Technology Data Exchange (ETDEWEB)

Mishra, Debaraj [Mineral and Material Processing Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Department of Microbiology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, Dong J. [Mineral and Material Processing Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350 (Korea, Republic of)], E-mail: djkim@kigam.re.kr; Ralph, David E. [AJ Parker CRC for Hydrometallurgy, Murdoch University, South Street Murdoch, Perth 6153 (Australia); Ahn, Jong G. [Mineral and Material Processing Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Rhee, Young H. [Department of Microbiology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

2008-04-15

Bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. The first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. In the second stage, the acidic medium was utilized for the leaching process. Nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium by the action of sulfuric acid that was produced by acidophilic leaching bacteria. Experiments were conducted varying the reaction time, amount of spent catalysts, amount of elemental sulfur and temperature. At 50 g/L spent catalyst concentration and 20 g/L elemental sulfur, 88.3% Ni, 46.3% Mo, and 94.8% V were recovered after 7 days. Chemical leaching with commercial sulfuric acid of the similar amount that produced by bacteria was compared. Thermodynamic parameters were calculated and the nature of reaction was found to be exothermic. Leaching kinetics of the metals was represented by different reaction kinetic equations, however, only diffusion controlled model showed the best correlation here. During the whole process Mo showed low dissolution because of substantiate precipitation with leach residues as MoO{sub 3}. Bioleach residues were characterized by EDX and XRD.

Bioleaching of pollymetallic sulphide concentrate using thermophilic bacteria

Directory of Open Access Journals (Sweden)

Vuković Milovan

2014-01-01

Full Text Available An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C. Following isolation and adaptation, the culture was used in a batch bioleach test employing a 5-l glass standard magnetic agitated and aerated reactor, for the bioleaching of a copper-lead-zinc collective concentrate. The culture exhibited stable leach performance over the period of leach operation and overall copper and zinc extractions higher than 97%. Lead sulphide is transformed into lead sulphate remaining in the bioleach residue due to the low solubility in sulphate media. Brine leaching of bioleach residue yields 95% lead extraction. [Projekat Ministarstva nauke Republike Srbije, br. 34023

Effect of solids concentration on removal of heavy metals from mine tailings via bioleaching

International Nuclear Information System (INIS)

Liu Yunguo; Zhou Ming; Zeng Guangming; Li Xin; Xu Weihua; Fan Ting

2007-01-01

Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The objective of this work is to demonstrate the feasibility to remove heavy metals from mine tailings with the use of bioleaching and meanwhile to investigate the effect of solids concentration on removal of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria and the transformation of heavy metal forms after the bioleaching process. This work showed the laboratory results of bioleaching experiments on Pb-Zn-Cu mine tailings. The results showed that 98.08% Zn, 96.44% Cu, and 43.52% Pb could be removed from mine tailings by the bioleaching experiment after 13 days at 1% (w/v) solids concentration and the rates of pH reduction, ORP rise and sulfate production were reduced with the increase of solids concentration, due to the buffering capacity of mine tailing solids. The results also indicated that solid concentration 1% was found to be best to bacterial activity and metal solubilization of the five solids concentration tested (1%, 2%, 5%, 8% and 10%) under the chosen experimental conditions. In addition, the bioleaching had a significant impact on changes in partitioning of heavy metals

Effect of solids concentration on removal of heavy metals from mine tailings via bioleaching

Energy Technology Data Exchange (ETDEWEB)

Liu Yunguo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China)]. E-mail: axore@163.com; Zhou Ming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Zeng Guangming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Li Xin [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Xu Weihua [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Fan Ting [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China)

2007-03-06

Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The objective of this work is to demonstrate the feasibility to remove heavy metals from mine tailings with the use of bioleaching and meanwhile to investigate the effect of solids concentration on removal of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria and the transformation of heavy metal forms after the bioleaching process. This work showed the laboratory results of bioleaching experiments on Pb-Zn-Cu mine tailings. The results showed that 98.08% Zn, 96.44% Cu, and 43.52% Pb could be removed from mine tailings by the bioleaching experiment after 13 days at 1% (w/v) solids concentration and the rates of pH reduction, ORP rise and sulfate production were reduced with the increase of solids concentration, due to the buffering capacity of mine tailing solids. The results also indicated that solid concentration 1% was found to be best to bacterial activity and metal solubilization of the five solids concentration tested (1%, 2%, 5%, 8% and 10%) under the chosen experimental conditions. In addition, the bioleaching had a significant impact on changes in partitioning of heavy metals.

Relationship between microbial community dynamics and process performance during thermophilic sludge bioleaching.

Science.gov (United States)

Chen, Shen-Yi; Chou, Li-Chieh

2016-08-01

Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic condition, thereby providing an option for biotreatment of wasted sludge generated from wastewater treatment. The purposes of this study were to establish a molecular biology technique, real-time PCR, for the detection and enumeration of the sulfur-oxidizing bacteria during the thermophilic sludge bioleaching. The 16S rRNA gene for real-time PCR quantification targeted the bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidithiobacillus caldus. The specificity and stringency for thermophilic sulfur-oxidizing bacteria were tested before the experiments of monitoring the bacterial community, bacterial number during the thermophilic sludge bioleaching and the future application on testing various environmental samples. The results showed that S. acidophilus was identified as the dominant sulfur-oxidizing bacteria, while A. caldus and S. thermosulfidooxidans occurred in relatively low numbers. The total number of the sulfur-oxidizing bacteria increased during the thermophilic bioleaching process. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS, and solubilization of heavy metal were found to correlate well with the population of thermophilic sulfur-oxidizing bacteria during the bioleaching process. The real-time PCR used in this study is a suitable method to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.

Changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using Acidithiobacillus thiooxidans

International Nuclear Information System (INIS)

NareshKumar, R.; Nagendran, R.

2008-01-01

Studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. Indigenous sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. Solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. However, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 and 68%, respectively. These findings indicate that despite its high potential for removal of heavy metals from contaminated soils, bioleaching results in undesirable dissolution/loss of essential plant nutrients. This aspect warrants urgent attention and detailed studies to evaluate the appropriateness of the technique for field application

Changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using Acidithiobacillus thiooxidans

Energy Technology Data Exchange (ETDEWEB)

NareshKumar, R. [Centre for Environmental Studies, Anna University, Chennai 600025 (India)], E-mail: nareshkrish@hotmail.com; Nagendran, R. [Centre for Environmental Studies, Anna University, Chennai 600025 (India)

2008-08-15

Studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. Indigenous sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. Solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. However, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 and 68%, respectively. These findings indicate that despite its high potential for removal of heavy metals from contaminated soils, bioleaching results in undesirable dissolution/loss of essential plant nutrients. This aspect warrants urgent attention and detailed studies to evaluate the appropriateness of the technique for field application.

Rock weathering by indigenous heterotrophic bacteria of Bacillus spp. at different temperature: a laboratory experiment

Science.gov (United States)

Štyriaková, I.; Štyriak, I.; Oberhänsli, H.

2012-07-01

The bio-weathering of basalt, granite and gneiss was experimentally investigated in this study. These rock-forming minerals weathered more rapidly via the ubiquitous psychrotrophic heterotrophic bacteria . With indigenous bacteria of Bacillus spp. from sediments of Lake Baikal, we traced the degradation process of silicate minerals to understand the weathering processes occurring at the change temperature in the subsurface environment with organic input. The bacteria mediated dissolution of minerals was monitored with solution and solid chemistry, X-ray analyses as well as microscopic techniques. We determined the impact of the bacteria on the mineral surface and leaching of K, Ca, Mg, Si, Fe, and Al from silicate minerals. In the samples the release of major structural elements of silicates was used as an overall indicator of silicate mineral degradation at 4°C and 18°C from five medium exchanges over 255 days of rock bioleaching. The increase of temperature importantly affected the efficiency of Fe extraction from granite and basalt as well as Si extraction from granite and gneiss. In comparison with elemental extraction order at 4°C, Ca was substituted first by Fe or Si. It is evident that temperature influences rock microbial weathering and results in a change of elements extraction.

Enhancement of gold recovery using bioleaching from gold concentrate

Science.gov (United States)

Choi, S. H.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

2012-04-01

The gold in refractory ores is encapsulated as fine particles (sometimes at a molecular level) in the crystal structure of the sulfide (typically pyrite with or without arsenopyrite) matrix. This makes it impossible to extract a significant amount of refractory gold by cyanidation since the cyanide solution cannot penetrate the pyrite/arsenopyrite crystals and dissolve gold particles, even after fine grinding. To effectively extract gold from these ores, an oxidative pretreatment is necessary to break down the sulfide matrix. The most popular methods of pretreatment include nitric acid oxidation, roasting, pressure oxidation and biological oxidation by microorganisms. This study investigated the bioleaching efficiency of Au concentrate under batch experimental conditions (adaptation cycles and chemical composition adaptation) using the indigenous acidophilic bacteria collected from gold mine leachate in Sunsin gold mine, Korea. We conducted the batch experiments at two different chemical composition (CuSO4 and ZnSO4), two different adaptation cycles 1'st (3 weeks) and 2'nd (6 weeks). The results showed that the pH in the bacteria inoculating sample decreased than initial condition and Eh increased. In the chemical composition adaptation case, the leached accumulation content of Fe and Pb was exhibited in CuSO4 adaptation bacteria sample more than in ZnSO4 adaptation bacteria samples, possibly due to pre-adaptation effect on chalcopyrite (CuFeS2) in gold concentrate. And after 21 days on the CuSO4 adaptation cycles case, content of Fe and Pb was appeared at 1'st adaptation bacteria sample(Fe - 1.82 and Pb - 25.81 times per control sample) lower than at 2'nd adaptation bacteria sample(Fe - 2.87 and Pb - 62.05 times per control sample). This study indicates that adaptation chemical composition and adaptation cycles can play an important role in bioleaching of gold concentrate in eco-/economic metallurgy process.

Insights into the relation between adhesion force and chalcopyrite-bioleaching by Acidithiobacillus ferrooxidans.

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Zhu, Jianyu; Wang, Qianfen; Zhou, Shuang; Li, Qian; Gan, Min; Jiang, Hao; Qin, Wenqing; Liu, Xueduan; Hu, Yuehua; Qiu, Guanzhou

2015-02-01

This paper presents a study on the relation between bacterial adhesion force and bioleaching rate of chalcopyrite, which sheds light on the influence of interfacial interaction on bioleaching behavior. In our research, Acidithiobacillus ferrooxidans (A. ferrooxidans) were adapted to grow with FeSO4 · 7H2O, element sulfur or chalcopyrite. Then, surface properties of Acidithiobacillus ferrooxidans and chalcopyrite were analyzed by contact angle, zeta potential and Fourier transform infrared spectroscopy (FTIR). Adhesion force between bacteria and chalcopyrite was measured by atomic force microscopy (AFM). Attachment and bioleaching behaviors were also monitored. The results showed that A. ferrooxidans adapted with chalcopyrite exhibited the strongest adhesion force to chalcopyrite and the highest bioleaching rate. Culture adapted with sulfur bacteria took second place and FeSO4 · 7H2O-adapted bacteria were the lowest. Bioleaching rate and bacterial attachment capacity were positively related to bacterial adhesion force, which is affected by the nature of energy source. According to this work, the attachment of bacteria to chalcopyrite surface is one of the most important aspects that influence the bioleaching process of chalcopyrite. Copyright © 2014 Elsevier B.V. All rights reserved.

Bioleaching mechanism of Zn, Pb, In, Ag, Cd and As from Pb/Zn smelting slag by autotrophic bacteria.

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Wang, Jia; Huang, Qifei; Li, Ting; Xin, Baoping; Chen, Shi; Guo, Xingming; Liu, Changhao; Li, Yuping

2015-08-15

A few studies have focused on release of valuable/toxic metals from Pb/Zn smelting slag by heterotrophic bioleaching using expensive yeast extract as an energy source. The high leaching cost greatly limits the practical potential of the method. In this work, autotrophic bioleaching using cheap sulfur or/and pyrite as energy matter was firstly applied to tackle the smelting slag and the bioleaching mechanisms were explained. The results indicated autotrophic bioleaching can solubilize valuable/toxic metals from slag, yielding maximum extraction efficiencies of 90% for Zn, 86% for Cd and 71% for In, although the extraction efficiencies of Pb, As and Ag were poor. The bioleaching performance of Zn, Cd and Pb was independent of leaching system, and leaching mechanism was acid dissolution. A maximum efficiency of 25% for As was achieved by acid dissolution in sulfursulfur oxidizing bacteria (S-SOB), but the formation of FeAsO4 reduced extraction efficiency in mixed energy source - mixed culture (MS-MC). Combined works of acid dissolution and Fe(3+) oxidation in MS-MC was responsible for the highest extraction efficiency of 71% for In. Ag was present in the slag as refractory AgPb4(AsO4)3 and AgFe2S3, so extraction did not occur. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Effect of Different Additives and Medium on the Bioleaching of Molybdenite for Cu and Mo Extraction Using Mix Mesophilic Microorganism

Directory of Open Access Journals (Sweden)

Hadi Abdollahia

2013-06-01

Full Text Available Bioleaching processes for extraction of Cu and Mo from molybdenite cons. are more environmentally friendly and consume less energy than conventional technologies, yet less economically efficient. One necessary step towards arriving at a cost-effective bioleaching process is using appropriate methodology to optimize pertinent factors in such processes. To this end, the present study employed Response Surface Methodology to optimize important factors in a molybdenite bioleaching process by mix mesophilic microorganism using shake flasks. The effect of change in the levels of molybdenite concentration, pyrite and silver ion concentration as additives - in the range 3-9%, 1-5%, and 0-1.2gr/l, respectively - on the rate of Cu and Mo bioleaching was studied using a Central Composite Design. The results showed a statistically significant effect of silver ion and molybdenite concentration, and to a lesser pyrite concentration, on the rate of bioleaching of Cu and Mo. Further, different mediums and additives were evaluated for copper and molybdenum extraction from molybdenite concentrate in bioleaching process. Small amounts of silver (100mgr/l AgSO4 dramatically accelerated the copper dissolution process. Addition of FeS2 and sulfur with ferrous sulfate accelerated the acidification and raised the oxidation-reduction potential of solution (medium with an inoculation of 15% (v/v of active and adapted indigenous mesophilic bacteria, thus resulting in an overall increase in Mo dissolution efficiency.

Multi-column bioleaching of a uranium ore

International Nuclear Information System (INIS)

Meng Yunsheng; Zheng Ying; Liu Hui; Cheng Hao

2014-01-01

The technology of bioleaching uranium ore can increase the uranium leaching rate and shorten the leaching uranium period, save consumption of acid and oxidant, lower production costs. An experiment on multi-column bioleaching of a uranium ore was done using mesophilic bacteria, the average uranium recovery of 90% was achieved in 39 days. Compared with traditional process, leaching period was shortened to 39 d from 59 d, acid consumption and liquid-solid ratio were also reduced. The results showed it is suitable to bioleach the uranium ore. (authors)

Practice and prospect on bioleaching of uranium ore in China

International Nuclear Information System (INIS)

Liu Jian; Fan Baotuan; Meng Yunsheng; Zheng Ying; Liu Chao; Zhou Lei

2008-01-01

Developing situation on bioleaching of uranium ore in China is introduced. The selection and domestication of bacteria, development and application of biocntact oxidation tank, and practice on bioleaching of uranium ore in China are retrospeted and prospected. (authors)

The community dynamics of major bioleaching microorganisms during chalcopyrite leaching under the effect of organics.

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Li, Qihou; Tian, Ye; Fu, Xian; Yin, Huaqun; Zhou, Zhijun; Liang, Yiting; Qiu, Guanzhou; Liu, Jie; Liu, Hongwei; Liang, Yili; Shen, Li; Cong, Jing; Liu, Xueduan

2011-08-01

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.

Bioleaching of Gold and Silver from Waste Printed Circuit Boards by Pseudomonas balearica SAE1 Isolated from an e-Waste Recycling Facility.

Science.gov (United States)

Kumar, Anil; Saini, Harvinder Singh; Kumar, Sudhir

2018-02-01

Indigenous bacterial strain Pseudomonas balearica SAE1, tolerant to e-waste toxicity was isolated from an e-waste recycling facility Exigo Recycling Pvt. Ltd., India. Toxicity tolerance of bacterial strain was analyzed using crushed (particle size ≤150 µm) waste computer printed circuit boards (PCBs)/liter (L) of culture medium. The EC 50 value for SAE1 was 325.7 g/L of the e-waste pulp density. Two-step bioleaching was then applied to achieve the dissolution of gold (Au) and silver (Ag) from the e-waste. To maximize precious metal dissolution, factors including pulp density, glycine concentration, pH level, and temperature were optimized. The optimization resulted in 68.5 and 33.8% of Au and Ag dissolution, respectively, at a pH of 9.0, a pulp density of 10 g/L, a temperature of 30 °C, and a glycine concentration of 5 g/L. This is the first study of Au and Ag bioleaching using indigenous e-waste bacteria and its analysis to determine e-waste toxicity tolerance.

The bioleaching potential of a bacterial consortium.

Science.gov (United States)

Latorre, Mauricio; Cortés, María Paz; Travisany, Dante; Di Genova, Alex; Budinich, Marko; Reyes-Jara, Angélica; Hödar, Christian; González, Mauricio; Parada, Pilar; Bobadilla-Fazzini, Roberto A; Cambiazo, Verónica; Maass, Alejandro

2016-10-01

This work presents the molecular foundation of a consortium of five efficient bacteria strains isolated from copper mines currently used in state of the art industrial-scale biotechnology. The strains Acidithiobacillus thiooxidans Licanantay, Acidiphilium multivorum Yenapatur, Leptospirillum ferriphilum Pañiwe, Acidithiobacillus ferrooxidans Wenelen and Sulfobacillus thermosulfidooxidans Cutipay were selected for genome sequencing based on metal tolerance, oxidation activity and bioleaching of copper efficiency. An integrated model of metabolic pathways representing the bioleaching capability of this consortium was generated. Results revealed that greater efficiency in copper recovery may be explained by the higher functional potential of L. ferriphilum Pañiwe and At. thiooxidans Licanantay to oxidize iron and reduced inorganic sulfur compounds. The consortium had a greater capacity to resist copper, arsenic and chloride ion compared to previously described biomining strains. Specialization and particular components in these bacteria provided the consortium a greater ability to bioleach copper sulfide ores. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fractionation study in bioleached metallurgy wastes using six-step sequential extraction.

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Krasnodebska-Ostrega, Beata; Pałdyna, Joanna; Kowalska, Joanna; Jedynak, Łukasz; Golimowski, Jerzy

2009-08-15

The stored metallurgy wastes contain residues from ore processing operations that are characterized by relatively high concentrations of heavy metals. The bioleaching process makes use of bacteria to recover elements from industrial wastes and to decrease potential risk of environmental contamination. Wastes were treated by solutions containing bacteria. In this work, the optimized six-stage sequential extraction procedure was applied for the fractionation of Ni, Cr, Fe, Mn, Cu and Zn in iron-nickel metallurgy wastes deposited in Southern Poland (Szklary). Fractionation and total concentrations of elements in wastes before and after various bioleaching treatments were studied. Analyses of the extracts were performed by ICP-MS and FAAS. To achieve the most effective bioleaching of Zn, Cr, Ni, Cu, Mn, Fe the usage of both autotrophic and heterotrophic bacteria in sequence, combined with flushing of the residue after bioleaching is required. 80-100% of total metal concentrations were mobilized after the proposed treatment. Wastes treated according to this procedure could be deposited without any risk of environmental contamination and additionally the metals could be recovered for industrial purposes.

AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.

Science.gov (United States)

González, Alex; Bellenberg, Sören; Mamani, Sigde; Ruiz, Lina; Echeverría, Alex; Soulère, Laurent; Doutheau, Alain; Demergasso, Cecilia; Sand, Wolfgang; Queneau, Yves; Vera, Mario; Guiliani, Nicolas

2013-04-01

Biofilm formation plays a pivotal role in bioleaching activities of bacteria in both industrial and natural environments. Here, by visualizing attached bacterial cells on energetic substrates with different microscopy techniques, we obtained the first direct evidence that it is possible to positively modulate biofilm formation of the extremophilic bacterium Acidithiobacillus ferrooxidans on sulfur and pyrite surfaces by using Quorum Sensing molecules of the N-acylhomoserine lactone type (AHLs). Our results revealed that AHL-signaling molecules with a long acyl chain (12 or 14 carbons) increased the adhesion of A. ferrooxidans cells to these substrates. In addition, Card-Fish experiments demonstrated that C14-AHL improved the adhesion of indigenous A. ferrooxidans cells from a mixed bioleaching community to pyrite. Finally, we demonstrated that this improvement of cell adhesion is correlated with an increased production of extracellular polymeric substances. Our results open up a promising means to develop new strategies for the improvement of bioleaching efficiency and metal recovery, which could also be used to control environmental damage caused by acid mine/rock drainage.

Enhancement of Au-Ag-Te contents in tellurium-bearing ore minerals via bioleaching

Science.gov (United States)

Choi, Nag-Choul; Cho, Kang Hee; Kim, Bong Ju; Lee, Soonjae; Park, Cheon Young

2018-03-01

The purpose of this study was to enhance the content of valuable metals, such as Au, Ag, and Te, in tellurium-bearing minerals via bioleaching. The ore samples composed of invisible Au and Au paragenesis minerals (such as pyrite, chalcopyrite, sphalerite and galena) in combination with tellurium-bearing minerals (hessite, sylvanite and Tellurobismuthite) were studied. Indigenous microbes from mine drainage were isolated and identified as Acidithiobacillus ferrooxidans, which were used in bioleaching after adaption to copper. The effect of the microbial adaption on the bioleaching performance was then compared with the results produced by the non-adaptive process. The microbial adaption enhanced the Au-Ag-Te contents in biological leaching of tellurium-bearing ore minerals. This suggests that bioleaching with adapted microbes can be used both as a pretreatment and in the main recovery processes of valuable metals.

Extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(III) ions and acidophilic bacteria.

Science.gov (United States)

Sand, Wolfgang; Gehrke, Tilman

2006-01-01

Extracellular polymeric substances seem to play a pivotal role in biocorrosion of metals and bioleaching, biocorrosion of metal sulfides for the winning of precious metals as well as acid rock drainage. For better control of both processes, the structure and function of extracellular polymeric substances of corrosion-causing or leaching bacteria are of crucial importance. Our research focused on the extremophilic bacteria Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, because of the "simplicity" and knowledge about the interactions of these bacteria with their substrate/substratum and their environment. For this purpose, the composition of the corresponding extracellular polymeric substances and their functions were analyzed. The extracellular polymeric substances of both species consist mainly of neutral sugars and lipids. The functions of the exopolymers seem to be: (i) to mediate attachment to a (metal) sulfide surface, and (ii) to concentrate iron(III) ions by complexation through uronic acids or other residues at the mineral surface, thus, allowing an oxidative attack on the sulfide. Consequently, dissolution of the metal sulfide is enhanced, which may result in an acceleration of 20- to 100-fold of the bioleaching process over chemical leaching. Experiments were performed to elucidate the importance of the iron(III) ions complexed by extracellular polymeric substances for strain-specific differences in oxidative activity for pyrite. Strains of A. ferrooxidans with a high amount of iron(III) ions in their extracellular polymeric substances possess greater oxidation activity than those with fewer iron(III) ions. These data provide insight into the function of and consequently the advantages that extracellular polymeric substances provide to bacteria. The role of extracellular polymeric substances for attachment under the conditions of a space station and resulting effects like biofouling, biocorrosion, malodorous gases, etc. will be discussed.

Significance of bioleaching method in dissolution of iron and in the quality improvement of non-metallics

Directory of Open Access Journals (Sweden)

Iveta Štyriaková

2006-12-01

Full Text Available Simple laboratory bioleaching experiments for the iron removal with heterotrophic bacteria on natural raw materials were conducted to explore a simple cyclic operation for a potential use at the industrial scale. Heterotrophic bacteria of Bacillus spp. growing in the presence of feldspar raw materials are able to dissolve iron. Anaerobic conditions Quickly formed by bacteria enable a simple manipulation with the sample solution. Insoluble Fe(III in the feldspars sample could be enzymatically dissolved as Fe3+ and also reduced to soluble Fe2+ by silicate bacteria of Bacillus spp. This metal was efficiently removed from the feldspars sample as documented by a Fe2O3 decrease (from 0.29 % to 0.12 % after bioleaching in the conical flask and by a Fe2O3 decrease (from 0.29 % to 0.19 % after bioleaching in the percolate column. Bioleaching of Fe was more effective in the conical flask. Iron-bearing minerals can be easily removed by magnetic separation, but ultra fine iron particles are difficult to treat by conventional mineral processing methods. Thus bioleaching is an attractive alternative for effective removal of iron minerals. The removal of iron with the whiteness increase should give a product, which is fit for industrial ceramic applications.

Impact of solvent extraction organics on adsorption and bioleaching of A. ferrooxidans and L. ferriphilum

Science.gov (United States)

Hualong, Yu; Xiaorong, Liu

2017-04-01

Copper solvent extraction entrained and dissoluted organics (SX organics) in the raffinate during SX operation can contaminated chalcopyrite ores and influence bioleaching efficiency by raffinate recycling. The adsorption and bioleaching of A. ferrooxidans and L. ferriphilum with contaminated ores were investigated. The results showed that, A. ferrooxidans and L. ferriphilum cells could adsorb quickly on minerals, the adsorption rate on contaminated ores were 83% and 60%, respectively, larger than on uncontaminated ores. However, in the bioleaching by the two kinds of acid bacterias, contaminated ores presented a lower bioleaching efficiency.

Bioleaching of heavy metals from sewage sludge by Acidithiobacillus thiooxidans. A comparative study

Energy Technology Data Exchange (ETDEWEB)

Wen, Ye-Ming; Wang, Qing-Ping; Chen, Zu-Liang [Fujian Normal Univ., Fuzhou (China). School of Environmental Science and Engineering; Tang, Caixian [La Trobe Univ., Melbourne, VIC (Australia). Dept. of Agricultural Sciences

2012-06-15

To understand the bioleaching of metals from sludge by Acidithiobacillus thiooxidans, the aims of this study were to evaluate the experimental conditions affecting the efficiency of removal of the metals, including solids concentration, initial pH, sulfur concentration and inoculum level were examined, and following the bioleaching mechanism was proposed. Materials and methods: A. thiooxidans were isolated from collected sludge samples containing bacteria from Fuzhou Jingshan sewage treatment plant, and identification of bacteria by sequencing the 16 s rDNA gene sequences. Conditions affecting the bioleaching and application were conducted by batch experiments. The analysis of Cr, Cu, Pb, and Zn was carried out using an atomic absorption spectrophotometer, and the pH and oxidation-reduction potential (ORP) were measured using a pH meter and an ORP meter. The results show that a high metal leaching efficiency was achieved at low solid concentrations due to decreases in buffering capacity. In addition, the best conditions of the bioleaching included 2 % (w/{nu}) solid concentration, 5.0 gL{sup -1} sulfur concentration, and 10 % ({nu}/{nu}) inoculum concentration, where the removal efficiencies of Cr, Cu, Pb, and Zn in sewage sludge was 43.6 %, 96.2 %, 41.6 %, and 96.5 %, respectively. We found that the bioleaching of Zn was governed by direct and indirect mechanisms, while the bioleaching of Cu, Pb, and Cr was mainly dominated by the bioleaching indirect mechanism. After processing with the proposed techniques, the heavy metals in the sewage sludge did meet the requirement of the national standards. (orig.)

Application of a mixed culture of adapted acidophilic bacteria in two-step bioleaching of spent lithium-ion laptop batteries

Science.gov (United States)

Heydarian, Ahmad; Mousavi, Seyyed Mohammad; Vakilchap, Farzane; Baniasadi, Mahsa

2018-02-01

The rapid increase in the production of electrical and electronic equipment, along with higher consumption of these products, has caused defective and obsolete equipment to accumulate in the environment. In this research, bioleaching of spent lithium-ion batteries (LIBs) used in laptops is carried out under two-step condition based on the bacterial activities of a mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. First, the best inoculum ratio of two acidophilic bacteria for the mixed culture is obtained. Next, adaptation is carried out successfully and the solid-to-liquid ratio reaches 40 g L-1. Response surface methodology is utilized to optimize the effective variables of initial pH, iron sulfate and sulfur concentrations. The maximum recovery of metal is about 99.2% for Li, 50.4% for Co and 89.4% for Ni under optimum conditions of 36.7 g L-1 iron sulfate concentration, 5.0 g L-1 sulfur concentration and initial pH of 1.5 for the best inoculum ratio of 3/2. Results of FE-SEM, XRD and FTIR analysis before and after bioleaching confirm that bacterial activity is a promising and effective route for metal recovery from spent LIBs. Toxicity assessment tests demonstrate the suitability of the bioleached residual as a nonhazardous material that meets environmental limitations for safe disposal.

Control of indigenous pathogenic bacteria in seafood

DEFF Research Database (Denmark)

Huss, Hans Henrik

1997-01-01

The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

Experimental study on bio-leaching of high sulphuric acid consumption uranium ore by adding sulphide

International Nuclear Information System (INIS)

Meng Yunsheng; Zheng Ying; Liu Hui; Cheng Hao; Zhou Lei; Liu Chao; Fan Baotuan; Li Jianhua

2012-01-01

In order to decrease acid consumption and increase leaching rate, an experiment on bio-leach-ing of low grade uranium ore by adding sulphide was done. Compared with conventional leaching method, the leaching rate of uranium is improved by 3% and the leaching period was reduced to 60 days from 90 days by bio-leaching method of adding sulphide. In order to decrease acid consumption with bio-leaching by adding sulphide obviously, robust bacteria to sulphide should be chosen. (authors)

Chemoorganotrophic Bioleaching of Olivine for Nickel Recovery

Directory of Open Access Journals (Sweden)

Yi Wai Chiang

2014-06-01

Full Text Available Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement in the fungal growth rate, to the promotion of particle degradation, and to the detachment of the stagnant biofilm around the particles. Furthermore, ultrasonic conditioning enhanced the selectivity of A. niger for nickel over iron to a value of 3.5. Pre-carbonating the olivine mineral, to enhance mineral liberation and change metal speciation, was also attempted, but did not result in improvement as a consequence of the mild pH of chemoorganotrophic bioleaching.

The influence of metal speciation in combustion waste on the efficiency of Cu, Pb, Zn, Cd, Ni and Cr bioleaching in a mixed culture of sulfur-oxidizing and biosurfactant-producing bacteria.

Science.gov (United States)

Karwowska, Ewa; Wojtkowska, Małgorzata; Andrzejewska, Dorota

2015-12-15

Metal leachability from ash and combustion slag is related to the physico-chemical properties, including their speciation in the waste. Metals speciation is an important factor that influences the efficiency of metal bioleaching from combustion wastes in a mixed culture of acidophilic and biosurfactant-producing bacteria. It was observed that individual metals tended to occur in different fractions, which reflects their susceptibility to bioleaching. Cr and Ni were readily removed from wastes when present with a high fraction bound to carbonates. Cd and Pb where not effectively bioleached when present in high amounts in a fraction bound to organic matter. The best bioleaching results were obtained for power plant slag, which had a high metal content in the exchangeable, bound to carbonates and bound to Fe and Mg oxides fractions- the metal recovery percentage for Zn, Cu and Ni from this waste exceeded 90%. Copyright © 2015 Elsevier B.V. All rights reserved.

Short communication: Adverse effect of surface-active reagents on the bioleaching of pyrite and chalcopyrite by Thiobacillus ferrooxidans.

Science.gov (United States)

Huerta, G; Escobar, B; Rubio, J; Badilla-Ohlbaum, R

1995-09-01

Oxidation of Fe(II) iron and bioleaching of pyrite and chalcopyrite by Thiobacillus ferrooxidans was adversely affected by isopropylxanthate, a flotation agent, and by LIX 984, a solvent-extraction agent, each at ≤ 1 g/l. The reagents/l were adsorbed on the bacterial surface, decreasing the bacteria's development and preventing biooxidation. Both reagents inhibited the bioleaching of pyrite and LIX 984 also inhibited the bioleaching of chalcopyrite.

Zinc bioleaching from an iron concentrate using Acidithiobacillus ferrooxidans strain from Hercules Mine of Coahuila, Mexico

Science.gov (United States)

Núñez-Ramírez, Diola Marina; Solís-Soto, Aquiles; López-Miranda, Javier; Pereyra-Alférez, Benito; Rutiaga-Quiñónes, Miriam; Medina-Torres, Luis; Medrano-Roldán, Hiram

2011-10-01

The iron concentrate from Hercules Mine of Coahuila, Mexico, which mainly contained pyrite and pyrrhotite, was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans ( A. ferrooxidans) to determine the ability of these bacteria on the leaching of zinc. The native bacteria were isolated from the iron concentrate of the mine. The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values, pulp density, and the ferrous sulfate concentration on the bioleaching process. The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A. ferrooxidans, which is enriched with a 9K Silverman medium under the optimum conditions of pH 2.0, 20 g/L pulp density, and 40 g/L FeSO4, increases the zinc extraction considerably observed by monitoring during15 d, i.e., the zinc concentration has a decrease of about 95% in the iron concentrate.

Continued Multicolumns Bioleaching for Low Grade Uranium Ore at a Certain Uranium Deposit

Directory of Open Access Journals (Sweden)

Gongxin Chen

2016-01-01

Full Text Available Bioleaching has lots of advantages compared with traditional heap leaching. In industry, bioleaching of uranium is still facing many problems such as site space, high cost of production, and limited industrial facilities. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains high fluoride. The analysis of chemical composition of ore shows that the grade of uranium is 0.208%, which is lower than that of other deposits. However, the fluoride content (1.8% of weight is greater than that of other deposits. This can be toxic for bacteria growth in bioleaching progress. In our continued multicolumns bioleaching experiment, the uranium recovery (89.5% of 4th column is greater than those of other columns in 120 days, as well as the acid consumption (33.6 g/kg. These results indicate that continued multicolumns bioleaching technology is suitable for leaching this type of ore. The uranium concentration of PLS can be effectively improved, where uranium recovery can be enhanced by the iron exchange system. Furthermore, this continued multicolumns bioleaching system can effectively utilize the remaining acid of PLS, which can reduce the sulfuric acid consumption. The cost of production of uranium can be reduced and this benefits the environment too.

Comparative study on the selective chalcopyrite bioleaching of a molybdenite concentrate with mesophilic and thermophilic bacteria.

Science.gov (United States)

Romano, P; Blázquez, M L; Alguacil, F J; Muñoz, J A; Ballester, A; González, F

2001-03-01

This study evaluates different bioleaching treatments of a molybdenite concentrate using mesophilic and thermophilic bacterial cultures. Further studies on the chemical leaching and the electrochemical behavior of the MoS(2) concentrate were carried out. Bioleaching tests showed a progressive removal of chalcopyrite from the molybdenite concentrate with an increase in temperature. Chemical leaching tests support the idea of an indirect attack of the concentrate. Electrochemical tests indicate that chalcopyrite dissolution is favored when molybdenite is present. Therefore, this type of bioleaching treatment could be applied to purify molybdenite flotation concentrates by selectively dissolving chalcopyrite.

Progress in bioleaching: part B: applications of microbial processes by the minerals industries.

Science.gov (United States)

Brierley, Corale L; Brierley, James A

2013-09-01

This review presents developments and applications in bioleaching and mineral biooxidation since publication of a previous mini review in 2003 (Olson et al. Appl Microbiol Biotechnol 63:249-257, 2003). There have been discoveries of newly identified acidophilic microorganisms that have unique characteristics for effective bioleaching of sulfidic ores and concentrates. Progress has been made in understanding and developing bioleaching of copper from primary copper sulfide minerals, chalcopyrite, covellite, and enargite. These developments point to low oxidation-reduction potential in concert with thermophilic bacteria and archaea as a potential key to the leaching of these minerals. On the commercial front, heap bioleaching of nickel has been commissioned, and the mineral biooxidation pretreatment of sulfidic-refractory gold concentrates is increasingly used on a global scale to enhance precious metal recovery. New and larger stirred-tank reactors have been constructed since the 2003 review article. One biooxidation-heap process for pretreatment of sulfidic-refractory gold ores was also commercialized. A novel reductive approach to bioleaching nickel laterite minerals has been proposed.

A combination of bioleaching and bioprecipitation for deep removal of contaminating metals from dredged sediment

Energy Technology Data Exchange (ETDEWEB)

Fang Di, E-mail: dfang@ouc.edu.cn [Department of Environmental Engineering, Ocean University of China, Qingdao 266100 (China); State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang Ruichang [Department of Environmental Engineering, Ocean University of China, Qingdao 266100 (China); Zhou Lixiang [Department of Environmental Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Li Jie [Department of Environmental Engineering, Ocean University of China, Qingdao 266100 (China)

2011-08-15

Highlights: {yields} Bioleaching-bioprecipitation can deeply cleanup sediment-borne metal contaminants. {yields} Bioleaching results in a sufficient solubilisation of sediment-borne metals. {yields} Bioprecipitation removes most of solubilised metals from sediment leachate at pH 3.7. {yields} Bioremoval of soluble Zn, Cu and Cr is due to the formation of ZnS, Cu{sub 2}S and CrOOH. {yields} Alkalization of bioleached sediment by Ca(OH){sub 2} excludes the risk of re-acidification. - Abstract: A linked microbial process comprising bioleaching with sulfate-oxidizing bacteria and bioprecipitation with sulfate-reducing bacteria operating sequentially was investigated to deeply remove contaminating metals from dredged sediment. The results showed that sediment bioleaching resulted in a sharp decrease in sediment pH from an initial pH {approx}7.6 to pH {approx}2.5 within 10-20 days, approximately 65% of the main heavy metals present (Zn + Cu + Cr) were solubilized, and most of the unsolubilized metals existed in residual form of sediment. The acidic leachate that resulted from sediment bioleaching was efficiently stripped of metal sulfates using a bioprecipitation reactor when challenged with influent as low as pH {approx}3.7. More than 99% of Zn{sup 2+}, 99% of Cu{sup 2+} and 90% of Cr{sup 3+} were removed from the leachate, respectively, due to the formation of ZnS, Cu{sub 2}S and CrOOH precipitates, as confirmed by SEM-EDS and XRD detection. It was also found that alkalization of bioleached sediment using Ca(OH){sub 2} excluded the risk of sediment re-acidification. The ability of the combined process developed in this study to deeply remove heavy metals in insoluble sulfides or hydroxides forms makes it particularly attractive for the treatment of different types of metal contaminants.

A combination of bioleaching and bioprecipitation for deep removal of contaminating metals from dredged sediment

International Nuclear Information System (INIS)

Fang Di; Zhang Ruichang; Zhou Lixiang; Li Jie

2011-01-01

Highlights: → Bioleaching-bioprecipitation can deeply cleanup sediment-borne metal contaminants. → Bioleaching results in a sufficient solubilisation of sediment-borne metals. → Bioprecipitation removes most of solubilised metals from sediment leachate at pH 3.7. → Bioremoval of soluble Zn, Cu and Cr is due to the formation of ZnS, Cu 2 S and CrOOH. → Alkalization of bioleached sediment by Ca(OH) 2 excludes the risk of re-acidification. - Abstract: A linked microbial process comprising bioleaching with sulfate-oxidizing bacteria and bioprecipitation with sulfate-reducing bacteria operating sequentially was investigated to deeply remove contaminating metals from dredged sediment. The results showed that sediment bioleaching resulted in a sharp decrease in sediment pH from an initial pH ∼7.6 to pH ∼2.5 within 10-20 days, approximately 65% of the main heavy metals present (Zn + Cu + Cr) were solubilized, and most of the unsolubilized metals existed in residual form of sediment. The acidic leachate that resulted from sediment bioleaching was efficiently stripped of metal sulfates using a bioprecipitation reactor when challenged with influent as low as pH ∼3.7. More than 99% of Zn 2+ , 99% of Cu 2+ and 90% of Cr 3+ were removed from the leachate, respectively, due to the formation of ZnS, Cu 2 S and CrOOH precipitates, as confirmed by SEM-EDS and XRD detection. It was also found that alkalization of bioleached sediment using Ca(OH) 2 excluded the risk of sediment re-acidification. The ability of the combined process developed in this study to deeply remove heavy metals in insoluble sulfides or hydroxides forms makes it particularly attractive for the treatment of different types of metal contaminants.

Bioleaching mechanism of heavy metals in the mixture of contaminated soil and slag by using indigenous Penicillium chrysogenum strain F1

International Nuclear Information System (INIS)

Deng, Xinhui; Chai, Liyuan; Yang, Zhihui; Tang, Chongjian; Wang, Yangyang; Shi, Yan

2013-01-01

Highlights: ► We use Penicillium chrysogenum growth experiment data to fit Gompertz model. ► We compared the removal efficiencies of bioleaching with chemical bioleaching. ► The morphology and resistant mechanism of P. chrysogenum were preliminary examined. ► Glucose oxidase activity produced by P. chrysogenum during bioleaching was studied. -- Abstract: The ability and bioleaching mechanism of heavy metals by Penicillium chrysogenum in soils contaminated with smelting slag were examined in this study. Batch experiments were performed to investigate the growth kinetics of P. chrysogenum, organic acids production and to compare the removal efficiencies of heavy metals between bioleaching with P. chrysogenum and chemical organic acids. The results showed that the bioleaching had higher removals than chemical leaching, and the removal percentages of Cd, Cu, Pb, Zn, Mn and Cr reached up to 74%, 59%, 24%, 55%, 57% and 25%, respectively. Removal efficiencies of heavy metals (15.41 mg/50 mL) by bioleaching were higher than chemical leaching with 0.5% of citric acid (15.15 mg/50 mL), oxalic acid (8.46 mg/50 mL), malic acid (11.35 mg/50 mL) and succinic acid (10.85 mg/50 mL). The results of transmission electron microscope (TEM) showed that no damage was obviously observed on the surface of the living cell except for thinner cell wall, discontinuous plasma membrane, compartmentalized lumen and concentrated cytoplasm during bioleaching process. The activity of extracellular glucose oxidase (GOD) produced by P. chrysogenum is influenced severely by the multi-heavy metal ions. The result implied that P. chrysogenum can be used to remove heavy metals from polluted soil and smeltery slag

Bioleaching mechanism of heavy metals in the mixture of contaminated soil and slag by using indigenous Penicillium chrysogenum strain F1

Energy Technology Data Exchange (ETDEWEB)

Deng, Xinhui [College of Metallurgical Science and Engineering, Central South University (China); College of Packing and Material Engineering, Hunan University of Technology (China); Chai, Liyuan, E-mail: liyuan.chai@yahoo.com [College of Metallurgical Science and Engineering, Central South University (China); Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution (China); Yang, Zhihui; Tang, Chongjian [College of Metallurgical Science and Engineering, Central South University (China); Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution (China); Wang, Yangyang; Shi, Yan [College of Metallurgical Science and Engineering, Central South University (China)

2013-03-15

Highlights: ► We use Penicillium chrysogenum growth experiment data to fit Gompertz model. ► We compared the removal efficiencies of bioleaching with chemical bioleaching. ► The morphology and resistant mechanism of P. chrysogenum were preliminary examined. ► Glucose oxidase activity produced by P. chrysogenum during bioleaching was studied. -- Abstract: The ability and bioleaching mechanism of heavy metals by Penicillium chrysogenum in soils contaminated with smelting slag were examined in this study. Batch experiments were performed to investigate the growth kinetics of P. chrysogenum, organic acids production and to compare the removal efficiencies of heavy metals between bioleaching with P. chrysogenum and chemical organic acids. The results showed that the bioleaching had higher removals than chemical leaching, and the removal percentages of Cd, Cu, Pb, Zn, Mn and Cr reached up to 74%, 59%, 24%, 55%, 57% and 25%, respectively. Removal efficiencies of heavy metals (15.41 mg/50 mL) by bioleaching were higher than chemical leaching with 0.5% of citric acid (15.15 mg/50 mL), oxalic acid (8.46 mg/50 mL), malic acid (11.35 mg/50 mL) and succinic acid (10.85 mg/50 mL). The results of transmission electron microscope (TEM) showed that no damage was obviously observed on the surface of the living cell except for thinner cell wall, discontinuous plasma membrane, compartmentalized lumen and concentrated cytoplasm during bioleaching process. The activity of extracellular glucose oxidase (GOD) produced by P. chrysogenum is influenced severely by the multi-heavy metal ions. The result implied that P. chrysogenum can be used to remove heavy metals from polluted soil and smeltery slag.

Characterization of lactic acid bacteria isolated from indigenous dahi ...

African Journals Online (AJOL)

Diversity and density of lactic acid bacteria from indigenous dahi were studied by the determination of morphological, cultural, physiological and biochemical characteristics. A total of 143 isolates were identified phenotypically and divided into three genera: Lactobacillus, Lactococcus and Streptococcus.

Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate

Science.gov (United States)

Bobadilla Fazzini, Roberto A.; Levican, Gloria

2010-01-01

The nature of the mineral–bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743–2747, 1998). On this respect, despite Acidithiobacilli—a ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell Fact 4(1):13, 2005)—has long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788–789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492–493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome. This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase. Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate. Electronic supplementary material The online version of this article (doi:10.1007/s00253-010-3063-8) contains supplementary material, which is available to authorized users. PMID:21191788

Contribution of increased mutagenesis to the evolution of pollutants-degrading indigenous bacteria

Science.gov (United States)

Ilmjärv, Tanel; Naanuri, Eve; Kivisaar, Maia

2017-01-01

Bacteria can rapidly evolve mechanisms allowing them to use toxic environmental pollutants as a carbon source. In the current study we examined whether the survival and evolution of indigenous bacteria with the capacity to degrade organic pollutants could be connected with increased mutation frequency. The presence of constitutive and transient mutators was monitored among 53 pollutants-degrading indigenous bacterial strains. Only two strains expressed a moderate mutator phenotype and six were hypomutators, which implies that constitutively increased mutability has not been prevalent in the evolution of pollutants degrading bacteria. At the same time, a large proportion of the studied indigenous strains exhibited UV-irradiation-induced mutagenesis, indicating that these strains possess error-prone DNA polymerases which could elevate mutation frequency transiently under the conditions of DNA damage. A closer inspection of two Pseudomonas fluorescens strains PC20 and PC24 revealed that they harbour genes for ImuC (DnaE2) and more than one copy of genes for Pol V. Our results also revealed that availability of other nutrients in addition to aromatic pollutants in the growth environment of bacteria affects mutagenic effects of aromatic compounds. These results also implied that mutagenicity might be affected by a factor of how long bacteria have evolved to use a particular pollutant as a carbon source. PMID:28777807

Sulfobacillus thermosulfidooxidans strain Cutipay enhances chalcopyrite bioleaching under moderate thermophilic conditions in the presence of chloride ion.

Science.gov (United States)

Bobadilla-Fazzini, Roberto A; Cortés, Maria Paz; Maass, Alejandro; Parada, Pilar

2014-12-01

Currently more than 90% of the world's copper is obtained through sulfide mineral processing. Among the copper sulfides, chalcopyrite is the most abundant and therefore economically relevant. However, primary copper sulfide bioleaching is restricted due to high ionic strength raffinate solutions and particularly chloride coming from the dissolution of ores. In this work we describe the chalcopyrite bioleaching capacity of Sulfobacillus thermosulfidooxidans strain Cutipay (DSM 27601) previously described at the genomic level (Travisany et al. (2012) Draft genome sequence of the Sulfobacillus thermosulfidooxidans Cutipay strain, an indigenous bacterium isolated from a naturally extreme mining environment in Northern Chile. J Bacteriol 194:6327-6328). Bioleaching assays with the mixotrophic strain Cutipay showed a strong increase in copper recovery from chalcopyrite concentrate at 50°C in the presence of chloride ion, a relevant inhibitory element present in copper bioleaching processes. Compared to the abiotic control and a test with Sulfobacillus acidophilus DSM 10332, strain Cutipay showed an increase of 42 and 69% in copper recovery, respectively, demonstrating its high potential for chalcopyrite bioleaching. Moreover, a genomic comparison highlights the presence of the 2-Haloacid dehalogenase predicted-protein related to a potential new mechanism of chloride resistance in acidophiles. This novel and industrially applicable strain is under patent application CL 2013-03335.

Bioleaching of multiple metals from contaminated sediment by moderate thermophiles.

Science.gov (United States)

Gan, Min; Jie, Shiqi; Li, Mingming; Zhu, Jianyu; Liu, Xinxing

2015-08-15

A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of metals from lead-zinc mine tailings using bioleaching and followed by sulfide precipitation.

Science.gov (United States)

Ye, Maoyou; Li, Guojian; Yan, Pingfang; Ren, Jie; Zheng, Li; Han, Dajian; Sun, Shuiyu; Huang, Shaosong; Zhong, Yujian

2017-10-01

Mine tailings often contain significant amounts of metals and sulfide, many traditional operations used to minerals was not as good as those currently available. This study investigated metals removal from lead-zinc mine tailings using bioleaching and followed by sulfide precipitation. Metals were dissolved from the tailings by the bacteria in a bioleaching reactor. During a 10% pulp density bioleaching experiment, approximately 0.82% Pb, 97.38% Zn, and 71.37% Fe were extracted after 50 days. With the pulp density of 10% and 20%, the dissolution of metals followed shrinking core kinetic model. Metals (Pb, Zn, and Fe) present in the pregnant bioleaching leachate. Metals were next precipitated as a sulfide phase using sodium sulfide (Na 2 S). Metal precipitations were selectively and quantitatively produced from the bioleaching leachate by adding Na 2 S. More than 99% of the zinc and 75% of the iron was precipitated using 25 g/L Na 2 S in the bioleaching leachate. The results in the study were to provide useful information for recovering or removing metals from lead-zinc mine tailings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent.

Science.gov (United States)

Chen, Peng; Xu, Ruixiang; Yan, Lei; Wu, Zhengrong; Wei, Yan; Zhao, Wenbin; Wang, Xin; Xie, Qinjian; Li, Hongyu

2017-05-22

Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (As 4 S 4 ). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.

Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent

Directory of Open Access Journals (Sweden)

Peng Chen

Full Text Available Abstract Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese. It contains over 90% tetra-arsenic tetrasulfide (As4S4. Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans. Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.

Microbial leaching of iron from pyrite by moderate thermophile chemolithotropic bacteria

International Nuclear Information System (INIS)

Ilyas, S.; Niazi, S.B.

2007-01-01

The present work was aimed at studying the bioleachability of iron from pyrite by the selected moderately thermophilic strains of acidophilic chemolithotrophic and acidophilic heterotrophic bacteria. These included Sulfobacillus thermosulfidooxidans (chemolithotroph) and an un-identified strain of acidophilic heterotroph (code 6A1TSB) isolated from local environments. As compared to inoculated flasks, dissolution of metal (due to acid leaching) was significantly low in the un-inoculated control flasks in all the experiments in ore. A decrease in the bioleaching activity was observed at the later stages of bioleaching of metal from ore. Among the strategies adopted to enhance the metal leaching rates, a mixed consortium of the metal adapted cultures of the above-mentioned bacteria was found to exhibit the maximum metal leaching efficiency. In all the flasks where high metal leaching rates were observed, concomitantly biomass production rates were also high indicating high growth rates. It showed that the metal bioleaching capability of the bacteria was associated with their growth. Pyrite contained 42% iron. (author)

Treatment of high-salinity chemical wastewater by indigenous bacteria--bioaugmented contact oxidation.

Science.gov (United States)

Li, Qiang; Wang, Mengdi; Feng, Jun; Zhang, Wei; Wang, Yuanyuan; Gu, Yanyan; Song, Cunjiang; Wang, Shufang

2013-09-01

A 90 m(3) biological contact oxidation system in chemical factory was bioaugmented with three strains of indigenous salt-tolerant bacteria. These three strains were screened from contaminative soil in situ. Their activity of growth and degradation was investigated with lab-scale experiments. Their salt-tolerant mechanism was confirmed to be compatible-solutes strategy for moderately halophilic bacteria, with amino acid and betaine playing important roles. The running conditions of the system were recorded for 150 days. The indigenous bacteria had such high suitability that the reactor got steady rapidly and the removal of COD maintained above 90%. It was introduced that biofilm fragments in sedimentation tank were inversely flowed to each reaction tank, and quantitative PCR demonstrated that this process could successfully maintain the bacterial abundance in the reaction tanks. In addition, the T-RFLP revealed that bioaugmented strains dominated over others in the biofilm. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bioleaching of vanadium from barren stone coal and its effect on the transition of vanadium speciation and mineral phase

Science.gov (United States)

Wang, Xin; Lin, Hai; Dong, Ying-bo; Li, Gan-yu

2018-03-01

This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial pH value, initial Fe2+ concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield (H2SO4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11wt% greater than the chemical leaching yield. The Community Bureau of Reference (BCR) sequential extraction results revealed that 88.62wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44wt%. The X-ray diffraction (XRD) and Fourier transform infrared (FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.

Hydrodynamic Study Of Column Bioleaching Processes

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Sadowski Zygmunt

2015-06-01

Full Text Available The modelling of flow leaching solution through the porous media has been considered. The heap bioleaching process can be tested using the column experimental equipment. This equipment was employed to the hydrodynamic studies of copper ore bioleaching. The copper ore (black shale ore with the support, inertial materials (glass small balls and polyethylene beads was used to the bioleaching tests. The packed beds were various composition, the ore/support ratio was changed. The correlation between the bed porosity and bioleaching kinetics, and copper recovery was investigated.

Impact of chemical oxidation on indigenous bacteria and mobilization of nutrients and subsequent bioremediation of crude oil-contaminated soil.

Science.gov (United States)

Xu, Jinlan; Deng, Xin; Cui, Yiwei; Kong, Fanxing

2016-12-15

Fenton pre-oxidation provides nutrients to promote bioremediation. However, the effects of the indigenous bacteria that remain following Fenton oxidation on nutrient mobilization and subsequent bioremediation remain unclear. Experiments were performed with inoculation with native bacteria and foreign bacteria or without inoculation after four regimens of stepwise pre-oxidations. The effects of the indigenous bacteria remaining after stepwise oxidation on nutrient mobilization and subsequent bioremediation over 80 days were investigated. After stepwise Fenton pre-oxidation at a low H 2 O 2 concentration (225×4), the remaining indigenous bacterial populations reached their peak (4.8±0.17×10 6 CFU/g), the nutrients were mobilized rapidly, and the subsequent bioremediation of crude oil was improved (biodegradation efficiency of 35%). However, after stepwise Fenton pre-oxidation at a high H 2 O 2 concentration (450×4), only 3.6±0.16×10 3 CFU/g of indigenous bacteria remained, and the indigenous bacteria that degrade C 15 -C 30 alkanes were inhibited. The nutrient mobilization was then highly limited, and only 19% of total petroleum hydrocarbon was degraded. Furthermore, the recovery period after the low H 2 O 2 concentration stepwise Fenton pre-oxidation (225×4) was less than 20 days, which was 20-30 days shorter than with the other pre-oxidation treatments. Therefore, stepwise Fenton pre-oxidation at a low H 2 O 2 concentration protects indigenous bacterial populations and improves the nutrient mobilization and subsequent bioremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

Bioleaching of ilmenite and basalt in the presence of iron-oxidizing and iron-scavenging bacteria

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Navarrete, Jesica U.; Cappelle, Ian J.; Schnittker, Kimberlin; Borrok, David M.

2013-04-01

Bioleaching has been suggested as an alternative to traditional mining techniques in extraterrestrial environments because it does not require extensive infrastructure and bulky hardware. In situ bioleaching of silicate minerals, such as those found on the moon or Mars, has been proposed as a feasible alternative to traditional extraction techniques that require either extreme heat and/or substantial chemical treatment. In this study, we investigated the biotic and abiotic leaching of basaltic rocks (analogues to those found on the moon and Mars) and the mineral ilmenite (FeTiO3) in aqueous environments under acidic (pH ˜ 2.5) and circumneutral pH conditions. The biological leaching experiments were conducted using Acidithiobacillus ferrooxidans, an iron (Fe)-oxidizing bacteria, and Pseudomonas mendocina, an Fe-scavenging bacteria. We found that both strains were able to grow using the Fe(II) derived from the tested basaltic rocks and ilmenite. Although silica leaching rates were the same or slightly less in the bacterial systems with A. ferrooxidans than in the abiotic control systems, the extent of Fe, Al and Ti released (and re-precipitated in new solid phases) was actually greater in the biotic systems. This is likely because the Fe(II) leached from the basalt was immediately oxidized by A. ferrooxidans, and precipitated into Fe(III) phases which causes a change in the equilibrium of the system, i.e. Le Chatelier's principle. Iron(II) in the abiotic experiment was allowed to build up in solution which led to a decrease in its overall release rate. For example, the percentage of Fe, Al and Ti leached (dissolved + reactive mineral precipitates) from the Mars simulant in the A. ferrooxidans experimental system was 34, 41 and 13% of the total Fe, Al and Ti in the basalt, respectively, while the abiotic experimental system released totals of only 11, 25 and 2%. There was, however, no measurable difference in the amounts of Fe and Ti released from ilmenite in the

The shift of microbial communities and their roles in sulfur and iron cycling in a copper ore bioleaching system

Science.gov (United States)

Niu, Jiaojiao; Deng, Jie; Xiao, Yunhua; He, Zhili; Zhang, Xian; van Nostrand, J. D.; Liang, Yili; Deng, Ye; Liu, Xueduan; Yin, Huaqun

2016-10-01

Bioleaching has been employed commercially to recover metals from low grade ores, but the production efficiency remains to be improved due to limited understanding of the system. This study examined the shift of microbial communities and S&Fe cycling in three subsystems within a copper ore bioleaching system: leaching heap (LH), leaching solution (LS) and sediment under LS. Results showed that both LH and LS had higher relative abundance of S and Fe oxidizing bacteria, while S and Fe reducing bacteria were more abundant in the Sediment. GeoChip analysis showed a stronger functional potential for S0 oxidation in LH microbial communities. These findings were consistent with measured oxidation activities to S0 and Fe2+, which were highest by microbial communities from LH, lower by those from LS and lowest form Sediment. Moreover, phylogenetic molecular ecological network analysis indicated that these differences might be related to interactions among microbial taxa. Last but not the least, a conceptual model was proposed, linking the S&Fe cycling with responsible microbial populations in the bioleaching systems. Collectively, this study revealed the microbial community and functional structures in all three subsystems of the copper ore, and advanced a holistic understanding of the whole bioleaching system.

The effect of bioleaching on sewage sludge pyrolysis.

Science.gov (United States)

Chen, Zhihua; Hu, Mian; Cui, Baihui; Liu, Shiming; Guo, Dabin; Xiao, Bo

2016-02-01

The effects of bioleaching on sewage sludge pyrolysis were studied. Sewage sludge was treated by bioleaching with solid concentrations of 6% (w/v), 8% (w/v), 10% (w/v). Results showed that bioleaching treatment could modify the physicochemical properties of sewage sludge and enhance the metals removal. The optimum removal efficiencies of heavy metals were achieved with solid concentration of 6% (w/v) bioleaching treatment: Cu, 73.08%; Zn, 78.67%; Pb, 24.65%; Cd, 79.46%. The characterization results of thermogravimetric analysis (TGA) showed that the bioleached sewage sludge with a 6% (w/v) solid concentration treatment was the easiest to decompose. Pyrolytic experiments of bioleached sewage sludge were performed in a laboratory-scale fixed bed reactor. Results indicated that bioleaching treatment greatly influenced the product yields and gas composition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison Analysis of Coal Biodesulfurization and Coal's Pyrite Bioleaching with Acidithiobacillus ferrooxidans

Science.gov (United States)

Hong, Fen-Fen; He, Huan; Liu, Jin-Yan; Tao, Xiu-Xiang; Zheng, Lei; Zhao, Yi-Dong

2013-01-01

Acidithiobacillus ferrooxidans (A. ferrooxidans) was applied in coal biodesulfurization and coal's pyrite bioleaching. The result showed that A. ferrooxidans had significantly promoted the biodesulfurization of coal and bioleaching of coal's pyrite. After 16 days of processing, the total sulfur removal rate of coal was 50.6%, and among them the removal of pyritic sulfur was up to 69.9%. On the contrary, after 12 days of processing, the coal's pyrite bioleaching rate was 72.0%. SEM micrographs showed that the major pyrite forms in coal were massive and veinlets. It seems that the bacteria took priority to remove the massive pyrite. The sulfur relative contents analysis from XANES showed that the elemental sulfur (28.32%) and jarosite (18.99%) were accumulated in the biotreated residual coal. However, XRD and XANES spectra of residual pyrite indicated that the sulfur components were mainly composed of pyrite (49.34%) and elemental sulfur (50.72%) but no other sulfur contents were detected. Based on the present results, we speculated that the pyrite forms in coal might affect sulfur biooxidation process. PMID:24288464

Bioleaching of a low grade sphalerite concentrate produced from tailings flotation

International Nuclear Information System (INIS)

Mehrabani, J. V.; Shafaei, S. Z.; Noaparast, M.; Mousavi, S. M.

2016-01-01

In this research, the zinc extraction from a low grade zinc concentrate produced from the accumulated flotation tailings was investigated using the bio leaching process. Zinc content was initially upgraded to 11.97% through flotation process. Bio leaching experiments were designed and carried out by a mixed culture of Acidithiobacillus ferro oxidans, Acidithiobacillus thio oxidans, Leptospirilium ferro oxidans, as well as a mixed moderate thermophile bacteria in the shake flasks. The effect of two bacteria types, the indigenous bacteria accompanied by concentrate sample and added mixture of bacteria, were evaluated. The term of indigenous bacteria refers to the bacteria which initially exists in the natural concentrate sample. The results showed that more than 87% and 94% of Zn was dissolved in the bio leaching condition of mesophile and moderate thermophile bacteria, respectively. Comparing the bio leaching and leaching tests indicate that mesophile bacteria improves the Zn extraction by 36%, in which the contribution of concentrate indigenous bacteria (test condition of non-inoculation) and added mesophile mixed bacteria were equal to 34% and 66%, respectively. In addition, moderate thermophile bacteria improves the sphalerite leaching up to 38% in which contribution of the concentrate indigenous bacteria and added moderate thermophile bacteria were about 50% separately.

Present and future of bioleaching in developing countries

OpenAIRE

Acevedo, Fernando

2002-01-01

Nowadays bioleaching occupies an increasingly important place among the available mining technologies. Today bioleaching is no longer a promising technology but an actual economical alternative for treating specific mineral ores. An important number of the current large-scale bioleaching operations are located in developing countries. This situation is determined by the fact that several developing countries have significant mineral reserves and by the characteristics of bioleaching that make...

Comparison Analysis of Coal Biodesulfurization and Coal’s Pyrite Bioleaching with Acidithiobacillus ferrooxidans

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Fen-Fen Hong

2013-01-01

Full Text Available Acidithiobacillus ferrooxidans (A. ferrooxidans was applied in coal biodesulfurization and coal’s pyrite bioleaching. The result showed that A. ferrooxidans had significantly promoted the biodesulfurization of coal and bioleaching of coal’s pyrite. After 16 days of processing, the total sulfur removal rate of coal was 50.6%, and among them the removal of pyritic sulfur was up to 69.9%. On the contrary, after 12 days of processing, the coal’s pyrite bioleaching rate was 72.0%. SEM micrographs showed that the major pyrite forms in coal were massive and veinlets. It seems that the bacteria took priority to remove the massive pyrite. The sulfur relative contents analysis from XANES showed that the elemental sulfur (28.32% and jarosite (18.99% were accumulated in the biotreated residual coal. However, XRD and XANES spectra of residual pyrite indicated that the sulfur components were mainly composed of pyrite (49.34% and elemental sulfur (50.72% but no other sulfur contents were detected. Based on the present results, we speculated that the pyrite forms in coal might affect sulfur biooxidation process.

Bioleaching of copper oxide ore by Pseudomonas aeruginosa

Science.gov (United States)

Shabani, M. A.; Irannajad, M.; Azadmehr, A. R.; Meshkini, M.

2013-12-01

Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bacterium that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows: particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1:80. Under these conditions, 53% of copper was extracted.

Presentation on mechanisms and applications of chalcopyrite and pyrite bioleaching in biohydrometallurgy - a presentation.

Science.gov (United States)

Tao, Huang; Dongwei, Li

2014-12-01

This review outlines classic and current research, scientific documents and research achievements in bioleaching, particularly in respect of the bioleaching of chalcopyrite and pyrite. The diversity and commonality of the microbial leaching process can be easily studied through comparing the bioleaching mechanism and the application of these two metal sulfides. The crystal, electronic and surface structures of chalcopyrite and pyrite are summarized in detail in this paper. It determines the specific and complicated interaction pathways, kinetics of the atmospheric/aqueous oxidation, and the control process of bioleaching of the minerals as the precondition. Bioleaching of metal sulfides is performed by a diverse group of microorganisms and microbial communities. The species of the bacteria which have a significant effect on leaching ores are miraculously diverse. The newly identified acidophilic microorganisms with unique characteristics for efficient bioleaching of sulfidic minerals are increasing sharply. The cell-to-cell communication mechanisms, which are still implicit, elusive and intangible at present day, have gradually become a research hotspot. The different mineralogy characteristics and the acid solubility of the metal sulfides (e.g., chalcopyrite and pyrite) cause two different dissolution pathways, the thiosulfate and the polysulfide pathways. The bioleaching mechanisms are categorized by contact (an electrostatic attachment) and noncontact (planktonic) process, with emphasis on the produce of extracellular polymeric substances and formation of biofilm on the surface of the metal sulfides in this paper. The division of the direct and indirect effect are not adopted due to the redox chain, the reduction of the ferric iron and oxidation of the ferrous iron. The molecular oxygen is reduced by the electrons extracted from the specific metal sulfide, via a redox chain forming a supercomplex spanning the periplasmic space and connecting both outer and inner

Use of large pieces of printed circuit boards for bioleaching to avoid 'precipitate contamination problem' and to simplify overall metal recovery.

Science.gov (United States)

Adhapure, N N; Dhakephalkar, P K; Dhakephalkar, A P; Tembhurkar, V R; Rajgure, A V; Deshmukh, A M

2014-01-01

Very recently bioleaching has been used for removing metals from electronic waste. Most of the research has been targeted to using pulverized PCBs for bioleaching where precipitate formed during bioleaching contaminates the pulverized PCB sample and making the overall metal recovery process more complicated. In addition to that, such mixing of pulverized sample with precipitate also creates problems for the final separation of non metallic fraction of PCB sample. In the present investigation we attempted the use of large pieces of printed circuit boards instead of pulverized sample for removal of metals. Use of large pieces of PCBs for bioleaching was restricted due to the chemical coating present on PCBs, the problem has been solved by chemical treatment of PCBs prior to bioleaching. In short,•Large pieces of PCB can be used for bioleaching instead of pulverized PCB sample.•Metallic portion on PCBs can be made accessible to bacteria with prior chemical treatment of PCBs.•Complete metal removal obtained on PCB pieces of size 4 cm × 2.5 cm with the exception of solder traces. The final metal free PCBs (non metallic) can be easily recycled and in this way the overall recycling process (metallic and non metallic part) of PCBs becomes simple.

Copper Bioleaching in China: Review and Prospect

OpenAIRE

Shenghua Yin; Leiming Wang; Eugie Kabwe; Xun Chen; Rongfu Yan; Kai An; Lei Zhang; Aixiang Wu

2018-01-01

The commercial application of copper bioleaching, an environmentally-friendly approach for low-grade and secondary mineral resources recycling, has increased worldwide since the 2000s. As the world’s second-largest economic entity and the largest developing country, China has the largest demand for metal resources, significantly advancing the theory and industrial technology of copper bioleaching. This paper reviews the exploration and application of copper bioleaching in China. Two typical b...

Quantitative monitoring of microbial species during bioleaching of a copper concentrate

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Sabrina Hedrich

2016-12-01

Full Text Available Monitoring of the microbial community in bioleaching processes is essential in order to control process parameters and enhance the leaching efficiency. Suitable methods are, however, limited as they are usually not adapted to bioleaching samples and often no taxon-specific assays are available in the literature for these types of consortia. Therefore, our study focused on the development of novel quantitative real-time PCR (qPCR assays for the quantification of Acidithiobacillus caldus, Leptospirillum ferriphilum, Sulfobacillus thermosulfidooxidans and Sulfobacillus benefaciens and comparison of the results with data from other common molecular monitoring methods in order to evaluate their accuracy and specificity. Stirred tank bioreactors for the leaching of copper concentrate, housing a consortium of acidophilic, moderately-thermophilic bacteria, relevant in several bioleaching operations, served as a model system. The microbial community analysis via qPCR allowed a precise monitoring of the evolution of total biomass as well as abundance of specific species. Data achieved by the standard fingerprinting methods, terminal restriction fragment length polymorphism (T-RFLP and capillary electrophoresis single strand conformation polymorphism (CE-SSCP on the same samples followed the same trend as qPCR data. The main added value of qPCR was, however, to provide quantitative data for each species whereas only relative abundance could be deduced from T-RFLP and CE-SSCP profiles. Additional value was obtained by applying two further quantitative methods which do not require nucleic acid extraction, total cell counting after SYBR Green staining and metal sulfide oxidation activity measurements via microcalorimetry. Overall, these complementary methods allow for an efficient quantitative microbial community monitoring in various bioleaching operations.

Quantitative Monitoring of Microbial Species during Bioleaching of a Copper Concentrate.

Science.gov (United States)

Hedrich, Sabrina; Guézennec, Anne-Gwenaëlle; Charron, Mickaël; Schippers, Axel; Joulian, Catherine

2016-01-01

Monitoring of the microbial community in bioleaching processes is essential in order to control process parameters and enhance the leaching efficiency. Suitable methods are, however, limited as they are usually not adapted to bioleaching samples and often no taxon-specific assays are available in the literature for these types of consortia. Therefore, our study focused on the development of novel quantitative real-time PCR (qPCR) assays for the quantification of Acidithiobacillus caldus, Leptospirillum ferriphilum, Sulfobacillus thermosulfidooxidans , and Sulfobacillus benefaciens and comparison of the results with data from other common molecular monitoring methods in order to evaluate their accuracy and specificity. Stirred tank bioreactors for the leaching of copper concentrate, housing a consortium of acidophilic, moderately thermophilic bacteria, relevant in several bioleaching operations, served as a model system. The microbial community analysis via qPCR allowed a precise monitoring of the evolution of total biomass as well as abundance of specific species. Data achieved by the standard fingerprinting methods, terminal restriction fragment length polymorphism (T-RFLP) and capillary electrophoresis single strand conformation polymorphism (CE-SSCP) on the same samples followed the same trend as qPCR data. The main added value of qPCR was, however, to provide quantitative data for each species whereas only relative abundance could be deduced from T-RFLP and CE-SSCP profiles. Additional value was obtained by applying two further quantitative methods which do not require nucleic acid extraction, total cell counting after SYBR Green staining and metal sulfide oxidation activity measurements via microcalorimetry. Overall, these complementary methods allow for an efficient quantitative microbial community monitoring in various bioleaching operations.

Use of large pieces of printed circuit boards for bioleaching to avoid ‘precipitate contamination problem’ and to simplify overall metal recovery

Science.gov (United States)

Adhapure, N.N.; Dhakephalkar, P.K.; Dhakephalkar, A.P.; Tembhurkar, V.R.; Rajgure, A.V.; Deshmukh, A.M.

2014-01-01

Very recently bioleaching has been used for removing metals from electronic waste. Most of the research has been targeted to using pulverized PCBs for bioleaching where precipitate formed during bioleaching contaminates the pulverized PCB sample and making the overall metal recovery process more complicated. In addition to that, such mixing of pulverized sample with precipitate also creates problems for the final separation of non metallic fraction of PCB sample. In the present investigation we attempted the use of large pieces of printed circuit boards instead of pulverized sample for removal of metals. Use of large pieces of PCBs for bioleaching was restricted due to the chemical coating present on PCBs, the problem has been solved by chemical treatment of PCBs prior to bioleaching. In short,•Large pieces of PCB can be used for bioleaching instead of pulverized PCB sample.•Metallic portion on PCBs can be made accessible to bacteria with prior chemical treatment of PCBs.•Complete metal removal obtained on PCB pieces of size 4 cm × 2.5 cm with the exception of solder traces. The final metal free PCBs (non metallic) can be easily recycled and in this way the overall recycling process (metallic and non metallic part) of PCBs becomes simple. PMID:26150951

Impact of solvent extraction organics on bioleaching by Acidithiobacillus ferrooxidans

Science.gov (United States)

Yu, Hualong; Liu, Xiaorong; Shen, Junhui; Chi, Daojie

2017-03-01

Solvent extraction organics (SX organics) entrained and dissoluted in the raffinate during copper SX operation, can impact bioleaching in case of raffinate recycling. The influence of SX organics on bioleaching process by Acidithiobacillus ferrooxidans (At. ferrooxidans) has been investigated. The results showed that, cells of At. ferrooxidans grew slower with contaminated low-grade chalcopyrite ores in shaken flasks bioleaching, the copper bioleaching efficiency reached 15%, lower than that of 24% for uncontaminated minerals. Obviously, the SX organics could adsorb on mineral surface and hinder its contact with bacterials, finanlly lead to the low bioleaching efficiency.

Arsenic biotransformation and release by bacteria indigenous to arsenic contaminated groundwater.

Science.gov (United States)

Paul, Dhiraj; Kazy, Sufia K; Banerjee, Tirtha Das; Gupta, Ashok K; Pal, Taraknath; Sar, Pinaki

2015-01-01

Arsenic (As) biotransformation and release by indigenous bacteria from As rich groundwater was investigated. Metabolic landscape of 173 bacterial isolates indicated broad catabolic repertoire including abundance of As(5+) reductase activity and abilities in utilizing wide ranges of organic and inorganic respiratory substrates. Abundance of As homeostasis genes and utilization of hydrocarbon as carbon/electron donor and As(5+) as electron acceptor were noted within the isolates. Sediment microcosm study (for 300 days) showed a pivotal role of metal reducing facultative anaerobic bacteria in toxic As(3+) release in aqueous phase. Inhabitant bacteria catalyze As transformation and facilitate its release through a cascade of reactions including mineral bioweathering and As(5+) and/or Fe(3+) reduction activities. Compared to anaerobic incubation with As(5+) reducing strains, oxic state and/or incubation with As(3+) oxidizing bacteria resulted in reduced As release, thus indicating a strong role of such condition or biocatalytic mechanism in controlling in situ As contamination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioleaching of spent Ni-Cd batteries by continuous flow system: Effect of hydraulic retention time and process load

International Nuclear Information System (INIS)

Zhao Ling; Yang Dong; Zhu Nanwen

2008-01-01

Spent Ni-Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0-4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni 0 ) were obtained separately in different acidity (pH 2.5-3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni-Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1 L d -1 and HRT was 3 days

Bioleaching of spent Ni-Cd batteries by continuous flow system: effect of hydraulic retention time and process load.

Science.gov (United States)

Zhao, Ling; Yang, Dong; Zhu, Nan-Wen

2008-12-30

Spent Ni-Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0-4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni0) were obtained separately in different acidity (pH 2.5-3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni-Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1Ld(-1) and HRT was 3 days.

Bioleaching of spent Ni-Cd batteries by continuous flow system: Effect of hydraulic retention time and process load

Energy Technology Data Exchange (ETDEWEB)

Zhao Ling; Yang Dong [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhu Nanwen [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)], E-mail: nwzhu@sina.com

2008-12-30

Spent Ni-Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0-4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni{sup 0}) were obtained separately in different acidity (pH 2.5-3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni-Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1 L d{sup -1} and HRT was 3 days.

Bioleaching of low-grade uranium ore using Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Pal, S.; Das, T.; Sukla, L.B.; Roy Chaudhury, G.; Pradhan, D.

2010-01-01

Bioleaching of uranium was carried out with Turamdih ore sample procured from Uranium Corporation of India Limited, Jaduguda. The bacterial strain that was used in the leaching experiments was isolated from the Jaduguda mine water sample. Efficiency of bioleaching was studied by varying parameters like pulp density and initial ferrous concentration as source of energy. It is observed that the efficiency of bioleaching was 49% at 10% pulp density (w/v) and initial pH 2.0. Addition of external has no effect on efficiency of bioleaching showing domination of direct leaching mechanism over indirect. (author)

Copper bioleaching from after-flotation waste using microfungi

Directory of Open Access Journals (Sweden)

Ewelina Kasińska-Pilut

2005-11-01

Full Text Available The aim of the research presented is an analysis of ways of utilizing microfloral autochthonous organisms from the after-flotation waste of the Gilow stockpile in order to bioleach copper. The alkaline character of the environment disables the use of the traditional processes of acid bioleaching, because of both the economical and environmental aspects. A research of the bioleaching process of the after-flotation waste was conducted using microfungi of the Aspergillus niger species, which dominate in the autochthonous environment. The metabolism of these microfungi, connected with the production of large amounts of organic acids, allowed to conceptualize their usage in the biohydrometalurgy copper processes. After isolating in a pure culture and multiplying the microfungal biomass Aspergillus niger, the experiments began. Weighed samples of the waste were covered with a selective medium and then inoculated with the microfungal biomass, playing the role of the bioleaching agent. After thirty days of incubation, the end product was chemically analyzed, showing effects of the conducted copper bioleaching process (81,23–87,98 %.

Isolation and identification of indigenous lactic acid bacteria from North Sumatra river buffalo milk

OpenAIRE

Heni Rizqiati; Cece Sumantr; Ronny Rachman Noor; E. Damayanthi; E. I. Rianti

2015-01-01

Buffalo milk is a source of various lactic acid bacteria (LAB) which is potential as culture starter as well as the probiotic. This study was conducted to isolate and identify LAB from indigenous North Sumatra river buffalo milk. Lactic acid bacteria was isolated and grown in medium De Man Rogosa Sharpe Agar (MRSA). The isolation was conducted to obtain pure isolate. The identification of LAB was studied in terms of morphology, physiology, biochemistry and survival on low pH. Morphology test...

Does bioleaching represent a biotechnological strategy for remediation of contaminated sediments?

Energy Technology Data Exchange (ETDEWEB)

Fonti, Viviana, E-mail: v.fonti@univpm.it; Dell' Anno, Antonio; Beolchini, Francesca

2016-09-01

Bioleaching is a consolidated biotechnology in the mining industry and in bio-hydrometallurgy, where microorganisms mediate the solubilisation of metals and semi-metals from mineral ores and concentrates. Bioleaching also has the potential for ex-situ/on-site remediation of aquatic sediments that are contaminated with metals, which represent a key environmental issue of global concern. By eliminating or reducing (semi-)metal contamination of aquatic sediments, bioleaching may represent an environmentally friendly and low-cost strategy for management of contaminated dredged sediments. Nevertheless, the efficiency of bioleaching in this context is greatly influenced by several abiotic and biotic factors. These factors need to be carefully taken into account before selecting bioleaching as a suitable remediation strategy. Here we review the application of bioleaching for sediment bioremediation, and provide a critical view of the main factors that affect its performance. We also discuss future research needs to improve bioleaching strategies for contaminated aquatic sediments, in view of large-scale applications. - Highlights: • Bioleaching may represent a sustainable strategy for contaminated dredged sediments • The performance is greatly influenced by several abiotic and biotic factors • Geochemical characteristics and metal partitioning have a key role • Sulphide minerals in the sediment are a favorable element • Microorganisms other than Fe/S oxidisers may open new perspectives.

Does bioleaching represent a biotechnological strategy for remediation of contaminated sediments?

International Nuclear Information System (INIS)

Fonti, Viviana; Dell'Anno, Antonio; Beolchini, Francesca

2016-01-01

Bioleaching is a consolidated biotechnology in the mining industry and in bio-hydrometallurgy, where microorganisms mediate the solubilisation of metals and semi-metals from mineral ores and concentrates. Bioleaching also has the potential for ex-situ/on-site remediation of aquatic sediments that are contaminated with metals, which represent a key environmental issue of global concern. By eliminating or reducing (semi-)metal contamination of aquatic sediments, bioleaching may represent an environmentally friendly and low-cost strategy for management of contaminated dredged sediments. Nevertheless, the efficiency of bioleaching in this context is greatly influenced by several abiotic and biotic factors. These factors need to be carefully taken into account before selecting bioleaching as a suitable remediation strategy. Here we review the application of bioleaching for sediment bioremediation, and provide a critical view of the main factors that affect its performance. We also discuss future research needs to improve bioleaching strategies for contaminated aquatic sediments, in view of large-scale applications. - Highlights: • Bioleaching may represent a sustainable strategy for contaminated dredged sediments • The performance is greatly influenced by several abiotic and biotic factors • Geochemical characteristics and metal partitioning have a key role • Sulphide minerals in the sediment are a favorable element • Microorganisms other than Fe/S oxidisers may open new perspectives

Enhanced bioleaching efficiency of metals from E-wastes driven by biochar

Energy Technology Data Exchange (ETDEWEB)

Wang, Shuhua; Zheng, Yue; Yan, Weifu; Chen, Lixiang [CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Dummi Mahadevan, Gurumurthy [CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); Zhao, Feng, E-mail: fzhao@iue.ac.cn [CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China)

2016-12-15

Electronic wastes (E-wastes) contain a huge amount of valuable metals that are worth recovering. Bioleaching has attracted widespread attention as an environment-friendly and low-cost technology for the recycling of E-wastes. To avoid the disadvantages of being time-consuming or having a relatively low efficiency, biochar with redox activity was used to enhance bioleaching efficiency of metals from a basic E-waste (i.e., printed circuit boards in this study). The role of biochar was examined through three basic processes: Carbon-mediated, Sulfur-mediated and Iron-mediated bioleaching pathways. Although no obvious enhancement of bioleaching performance was observed in the C-mediated and S-mediated systems, Fe-mediated bioleaching was significantly promoted by the participation of biochar, and its leaching time was decreased by one-third compared with that of a biochar-free system. By mapping the dynamic concentration of Fe(II) and Cu(II), biochar was proved to facilitate the redox action between Fe(II) to Fe(III), which resulted in effective leaching of Cu. Two dominant functional species consisting of Alicyclobacillus spp. and Sulfobacillus spp. may cooperate in the Fe-mediated bioleaching system, and the ratio of these two species was regulated by biochar for enhancing the efficiency of bioleaching. Hence, this work provides a method to improve bioleaching efficiency with low-cost solid redox media.

Enhanced bioleaching efficiency of metals from E-wastes driven by biochar

International Nuclear Information System (INIS)

Wang, Shuhua; Zheng, Yue; Yan, Weifu; Chen, Lixiang; Dummi Mahadevan, Gurumurthy; Zhao, Feng

2016-01-01

Electronic wastes (E-wastes) contain a huge amount of valuable metals that are worth recovering. Bioleaching has attracted widespread attention as an environment-friendly and low-cost technology for the recycling of E-wastes. To avoid the disadvantages of being time-consuming or having a relatively low efficiency, biochar with redox activity was used to enhance bioleaching efficiency of metals from a basic E-waste (i.e., printed circuit boards in this study). The role of biochar was examined through three basic processes: Carbon-mediated, Sulfur-mediated and Iron-mediated bioleaching pathways. Although no obvious enhancement of bioleaching performance was observed in the C-mediated and S-mediated systems, Fe-mediated bioleaching was significantly promoted by the participation of biochar, and its leaching time was decreased by one-third compared with that of a biochar-free system. By mapping the dynamic concentration of Fe(II) and Cu(II), biochar was proved to facilitate the redox action between Fe(II) to Fe(III), which resulted in effective leaching of Cu. Two dominant functional species consisting of Alicyclobacillus spp. and Sulfobacillus spp. may cooperate in the Fe-mediated bioleaching system, and the ratio of these two species was regulated by biochar for enhancing the efficiency of bioleaching. Hence, this work provides a method to improve bioleaching efficiency with low-cost solid redox media.

Enhanced bioleaching efficiency of metals from E-wastes driven by biochar.

Science.gov (United States)

Wang, Shuhua; Zheng, Yue; Yan, Weifu; Chen, Lixiang; Dummi Mahadevan, Gurumurthy; Zhao, Feng

2016-12-15

Electronic wastes (E-wastes) contain a huge amount of valuable metals that are worth recovering. Bioleaching has attracted widespread attention as an environment-friendly and low-cost technology for the recycling of E-wastes. To avoid the disadvantages of being time-consuming or having a relatively low efficiency, biochar with redox activity was used to enhance bioleaching efficiency of metals from a basic E-waste (i.e., printed circuit boards in this study). The role of biochar was examined through three basic processes: Carbon-mediated, Sulfur-mediated and Iron-mediated bioleaching pathways. Although no obvious enhancement of bioleaching performance was observed in the C-mediated and S-mediated systems, Fe-mediated bioleaching was significantly promoted by the participation of biochar, and its leaching time was decreased by one-third compared with that of a biochar-free system. By mapping the dynamic concentration of Fe(II) and Cu(II), biochar was proved to facilitate the redox action between Fe(II) to Fe(III), which resulted in effective leaching of Cu. Two dominant functional species consisting of Alicyclobacillus spp. and Sulfobacillus spp. may cooperate in the Fe-mediated bioleaching system, and the ratio of these two species was regulated by biochar for enhancing the efficiency of bioleaching. Hence, this work provides a method to improve bioleaching efficiency with low-cost solid redox media. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling of uranium bioleaching by Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Rashidi, A.; Safdari, J.; Roosta-Azad, R.; Zokaei-Kadijani, S.

2012-01-01

Highlights: ► A mathematical model for the mesophilic bioleaching of uraninite is introduced. ► New rate expressions are used for the iron precipitation and uranium leaching rates. ► Good fits of the model are obtained, while the values of the parameters are within the range expected. ► The model can be applied to other bioleaching processes under the same conditions. - Abstract: In this paper, a mathematical model for the mesophilic bioleaching of uraninite is developed. The case of constant temperature, pH, and initial ore concentration is considered. The model is validated by comparing the calculated and measured values of uranium extraction, ferric and ferrous iron in solution, and cell concentration. Good fits of the model were obtained, while the values of the parameters were within the range expected. New rate expressions were used for the iron precipitation and uranium leaching rates. The rates of chemical leaching and ferric precipitation are related to the ratio of ferric to ferrous in solution. The fitted parameters can be considered applicable only to this study. In contrast, the model equation is general and can be applied to bioleaching under the same conditions.

[Sewage sludge conditioning by bioleaching-dual PAC and PAM addition].

Science.gov (United States)

Liu, Chang-Geng; Zhang, Pan-Yue; Zeng, Guang-Ming; Liu, Yong-Gang

2010-09-01

Bioleaching-dual polyaluminum chloride (PAC) and polyacrylamide (PAM) addition was used to condition sewage sludge. The results showed that FeSO4 x 7H2O addition improved the bioleaching rate obviously with a fixed sulfur power dosage of 3 g x L(-1); when the FeSO4 x 7H2O dosage was 8 g x L(-1), the bioleaching lasted 1.5 d to decrease the sludge pH below 2. Bioleaching improved the sludge dewaterability significantly with a specific resistance to filtration (SRF) reduction of 77.52% from 6.45 x 10(10)s2 x g(-10 to 1.45 x 10(10)s2 x g(-1), but the bioleached sludge was still difficult to be dewatered. After adjusting the bioleached sludge pH to 6, PAC and PAM were used to enhance conditioning of the bioleached sludge. The results indicated that the optimal dosage was 200 mg x L(-1) for PAC or 50 mg x L(-1) for PAM when single chemical was used. When PAC and PAM were dually used, the optimal dosages of PAC and PAM were 100 mg x L(-1) and 25 mg x L(-1), respectively; SRF and moisture of sludge cake reduced to 2.02 x 10(8) s2 x g(-1) and 74.81%, respectively, showing good dewaterability of the treated sludge. Compared with the single use of PAC and PAM, the dual use of PAC and PAM showed the advantages of lower cost and better conditioning effect.

In situ characterization of natural pyrite bioleaching using electrochemical noise technique

Science.gov (United States)

Chen, Guo-bao; Yang, Hong-ying; Li, Hai-jun

2016-02-01

An in situ characterization technique called electrochemical noise (ECN) was used to investigate the bioleaching of natural pyrite. ECN experiments were conducted in four active systems (sulfuric acid, ferric-ion, 9k culture medium, and bioleaching solutions). The ECN data were analyzed in both the time and frequency domains. Spectral noise impedance spectra obtained from power spectral density (PSD) plots for different systems were compared. A reaction mechanism was also proposed on the basis of the experimental data analysis. The bioleaching system exhibits the lowest noise resistance of 0.101 MΩ. The bioleaching of natural pyrite is considered to be a bio-battery reaction, which distinguishes it from chemical oxidation reactions in ferric-ion and culture-medium (9k) solutions. The corrosion of pyrite becomes more severe over time after the long-term testing of bioleaching.

Metal removal from Municipal Solid Waste Incineration fly ash: A comparison between chemical leaching and bioleaching.

Science.gov (United States)

Funari, V; Mäkinen, J; Salminen, J; Braga, R; Dinelli, E; Revitzer, H

2017-02-01

Bio- and hydrometallurgical experimental setups at 2-l reactor scale for the processing of fly ash from municipal waste incinerators were explored. We aimed to compare chemical H 2 SO 4 leaching and bioleaching; the latter involved the use of H 2 SO 4 and a mixed culture of acidophilic bacteria. The leaching yields of several elements, including some of those considered as critical (Mg, Co, Ce, Cr, Ga, Nb, Nd, Sb and Sm), are provided. At the end of the experiments, both leaching methods resulted in comparable yields for Mg and Zn (>90%), Al and Mn (>85%), Cr (∼65%), Ga (∼60%), and Ce (∼50%). Chemical leaching showed the best yields for Cu (95%), Fe (91%), and Ni (93%), whereas bioleaching was effective for Nd (76%), Pb (59%), and Co (55%). The two leaching methods generated solids of different quality with respect to the original material as we removed and significantly reduced the metals amounts, and enriched solutions where metals can be recovered for example as mixed salts for further treatment. Compared to chemical leaching the bioleaching halved the use of H 2 SO 4 , i.e., a part of agent costs, as a likely consequence of bio-produced acid and improved metal solubility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bacteria associated with human saliva are major microbial components of Ecuadorian indigenous beers (chicha

Directory of Open Access Journals (Sweden)

Ana L. Freire

2016-04-01

Full Text Available Indigenous beers (chicha are part of the indigenous culture in Ecuador. The fermentation process of these beers probably relies on microorganisms from fermented substrates, environment and human microbiota. We analyzed the microbiota of artisanal beers (including a type of beer produced after chewing boiled cassava using bacterial culture and 16S ribosomal RNA (rRNA gene-based tag-encoded FLX amplicon pyrosequencing (bTEFAP. Surprisingly, we found that Streptococcus salivarius and Streptococcus mutans (part of the human oral microbiota were among the most abundant bacteria in chewed cassava and in non-chewed cassava beers. We also demonstrated that S. salivarius and S. mutans (isolated from these beers could proliferate in cassava mush. Lactobacillus sp. was predominantly present in most types of Ecuadorian chicha.

Electrochemical Applications in Metal Bioleaching.

Science.gov (United States)

Tanne, Christoph Kurt; Schippers, Axel

2017-12-10

Biohydrometallurgy comprises the recovery of metals by biologically catalyzed metal dissolution from solids in an aqueous solution. The application of this kind of bioprocessing is described as "biomining," referring to either bioleaching or biooxidation of sulfide metal ores. Acidophilic iron- and sulfur-oxidizing microorganisms are the key to successful biomining. However, minerals such as primary copper sulfides are recalcitrant to dissolution, which is probably due to their semiconductivity or passivation effects, resulting in low reaction rates. Thus, further improvements of the bioleaching process are recommendable. Mineral sulfide dissolution is based on redox reactions and can be accomplished by electrochemical technologies. The impact of electrochemistry on biohydrometallurgy affects processing as well as analytics. Electroanalysis is still the most widely used electrochemical application in mineralogical research. Electrochemical processing can contribute to bioleaching in two ways. The first approach is the coupling of a mineral sulfide to a galvanic partner or electrocatalyst (spontaneous electron transfer). This approach requires only low energy consumption and takes place without technical installations by the addition of higher redox potential minerals (mostly pyrite), carbonic material, or electrocatalytic ions (mostly silver ions). Consequently, the processed mineral (often chalcopyrite) is preferentially dissolved. The second approach is the application of electrolytic bioreactors (controlled electron transfer). The electrochemical regulation of electrolyte properties by such reactors has found most consideration. It implies the regulation of ferrous and ferric ion ratios, which further results in optimized solution redox potential, less passivation effects, and promotion of microbial activity. However, many questions remain open and it is recommended that reactor and electrode designs are improved, with the aim of finding options for simplified

Development of bioleaching: proteomics and genomics approach in metals extraction process

OpenAIRE

M. Azizur Rahman

2016-01-01

Microbes are key components of the structure and function of bioleaching process. Increasing consciousness of the role of microbes has led to a quick growth of descriptive and investigational studies of their abundance and activities. However, the detail information of complex functional molecules contain in promising microbes which are very important for understanding microbial processes in bioleaching, are lacking. Therefore, molecular functions of microbes in the bioleaching process are ve...

Indigenous bacteria and bacterial metabolic products in the gastrointestinal tract of broiler chickens.

Science.gov (United States)

Rehman, Habib Ur; Vahjen, Wilfried; Awad, Wageha A; Zentek, Jürgen

2007-10-01

The gastrointestinal tract is a dynamic ecosystem containing a complex microbial community. In this paper, the indigenous intestinal bacteria and the microbial fermentation profile particularly short chain fatty acids (SCFA), lactate, and ammonia concentrations are reviewed. The intestinal bacterial composition changes with age. The bacterial density of the small intestine increases with age and comprises of lactobacilli, streptococci, enterobacteria, fusobacteria and eubacteria. Strict anaerobes (anaerobic gram-positive cocci, Eubacterium spp., Clostridium spp., Lactobacillus spp., Fusobacterium spp. and Bacteroides) are predominating caecal bacteria in young broilers. Data from culture-based studies showed that bifidobacteria could not be isolated from young birds, but were recovered from four-week-old broilers. Caecal lactobacilli accounted for 1.5-24% of the caecal bacteria. Gene sequencing of caecal DNA extracts showed that the majority of bacteria belonged to Clostridiaceae. Intestinal bacterial community is influenced by the dietary ingredients, nutrient levels and physical structure of feed. SCFA and other metabolic products are affected by diet formulation and age. Additional studies are required to know the bacterial metabolic activities together with the community analysis of the intestinal bacteria. Feed composition and processing have great potential to influence the activities of intestinal bacteria towards a desired direction in order to support animal health, well-being and microbial safety of broiler meat.

Comparative Genomics Unravels the Functional Roles of Co-occurring Acidophilic Bacteria in Bioleaching Heaps

Science.gov (United States)

Zhang, Xian; Liu, Xueduan; Liang, Yili; Xiao, Yunhua; Ma, Liyuan; Guo, Xue; Miao, Bo; Liu, Hongwei; Peng, Deliang; Huang, Wenkun; Yin, Huaqun

2017-01-01

The spatial-temporal distribution of populations in various econiches is thought to be potentially related to individual differences in the utilization of nutrients or other resources, but their functional roles in the microbial communities remain elusive. We compared differentiation in gene repertoire and metabolic profiles, with a focus on the potential functional traits of three commonly recognized members (Acidithiobacillus caldus, Leptospirillum ferriphilum, and Sulfobacillus thermosulfidooxidans) in bioleaching heaps. Comparative genomics revealed that intra-species divergence might be driven by horizontal gene transfer. These co-occurring bacteria shared a few homologous genes, which significantly suggested the genomic differences between these organisms. Notably, relatively more genes assigned to the Clusters of Orthologous Groups category [G] (carbohydrate transport and metabolism) were identified in Sulfobacillus thermosulfidooxidans compared to the two other species, which probably indicated their mixotrophic capabilities that assimilate both organic and inorganic forms of carbon. Further inspection revealed distinctive metabolic capabilities involving carbon assimilation, nitrogen uptake, and iron-sulfur cycling, providing robust evidence for functional differences with respect to nutrient utilization. Therefore, we proposed that the mutual compensation of functionalities among these co-occurring organisms might provide a selective advantage for efficiently utilizing the limited resources in their habitats. Furthermore, it might be favorable to chemoautotrophs' lifestyles to form mutualistic interactions with these heterotrophic and/or mixotrophic acidophiles, whereby the latter could degrade organic compounds to effectively detoxify the environments. Collectively, the findings shed light on the genetic traits and potential metabolic activities of these organisms, and enable us to make some inferences about genomic and functional differences that might

Comparative Genomics Unravels the Functional Roles of Co-occurring Acidophilic Bacteria in Bioleaching Heaps

Directory of Open Access Journals (Sweden)

Xian Zhang

2017-05-01

Full Text Available The spatial-temporal distribution of populations in various econiches is thought to be potentially related to individual differences in the utilization of nutrients or other resources, but their functional roles in the microbial communities remain elusive. We compared differentiation in gene repertoire and metabolic profiles, with a focus on the potential functional traits of three commonly recognized members (Acidithiobacillus caldus, Leptospirillum ferriphilum, and Sulfobacillus thermosulfidooxidans in bioleaching heaps. Comparative genomics revealed that intra-species divergence might be driven by horizontal gene transfer. These co-occurring bacteria shared a few homologous genes, which significantly suggested the genomic differences between these organisms. Notably, relatively more genes assigned to the Clusters of Orthologous Groups category [G] (carbohydrate transport and metabolism were identified in Sulfobacillus thermosulfidooxidans compared to the two other species, which probably indicated their mixotrophic capabilities that assimilate both organic and inorganic forms of carbon. Further inspection revealed distinctive metabolic capabilities involving carbon assimilation, nitrogen uptake, and iron-sulfur cycling, providing robust evidence for functional differences with respect to nutrient utilization. Therefore, we proposed that the mutual compensation of functionalities among these co-occurring organisms might provide a selective advantage for efficiently utilizing the limited resources in their habitats. Furthermore, it might be favorable to chemoautotrophs' lifestyles to form mutualistic interactions with these heterotrophic and/or mixotrophic acidophiles, whereby the latter could degrade organic compounds to effectively detoxify the environments. Collectively, the findings shed light on the genetic traits and potential metabolic activities of these organisms, and enable us to make some inferences about genomic and functional

Bioleaching of heavy metal polluted sediment: influence of temperature and oxygen. Pt. 1

Energy Technology Data Exchange (ETDEWEB)

Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, 01062 Dresden (Germany); Zehnsdorf, A. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Umwelt- und Biotechnologisches Zentrum, Permoserstrasse 15, 04318 Leipzig (Germany); Goersch, K.; Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, 04318 Leipzig (Germany)

2006-08-15

A remediation process for heavy metal polluted sediment has previously been developed in which the heavy metals are removed from the sediment by solid-bed bioleaching using elemental sulfur (S{sup 0}): the added S{sup 0} is oxidized by the indigenous microbes to sulfuric acid that dissolves the heavy metals which are finally extracted by percolating water. In this process, the temperature is a factor crucially affecting the rate of S{sup 0} oxidation and metal solubilization. Here, the effect of temperature on the kinetics of S{sup 0} oxidation has been studied: oxidized Weisse Elster River sediment (dredged near Leipzig, Germany) was mixed with 2 % S{sup 0}, suspended in water and then leached at various temperatures. The higher the temperature was, the faster the S{sup 0} oxidized, and the more rapid the pH decreased. But temperatures above 35 C slowed down S{sup 0} oxidation, and temperatures above 45 C let the process - after a short period of acidification to pH 4.5 - stagnate. The latter may be explained by the presence of both neutrophilic to less acidophilic thermotolerant bacteria and acidophilic thermosensitive bacteria. Within 42 days, nearly complete S{sup 0} oxidation and maximum heavy metal solubilization only occurred at 30 to 45 C. The measured pH(t) courses were used to model the rate of S{sup 0} oxidation depending on the temperature using an extended Arrhenius equation. Since molecular oxygen is another factor highly influencing the activity of S{sup 0}-oxidizing bacteria, the effect of dissolved O{sub 2} (controlled by the O{sub 2} content in the gas supplied) on S{sup 0} oxidation was studied in suspension: the indigenous S{sup 0}-oxidizing bacteria reacted quite tolerant to low O{sub 2} concentrations; the rate of S{sup 0} oxidation - measured as the specific O{sub 2} consumption - was not affected until the O{sub 2} content of the suspension was below 0.05 mg/L, i.e., the S{sup 0}-oxidizing bacteria showed a high affinity to O{sub 2} with a

Soil burial method for plastic degradation performed by Pseudomonas PL-01, Bacillus PL-01, and indigenous bacteria

Science.gov (United States)

Shovitri, Maya; Nafi'ah, Risyatun; Antika, Titi Rindi; Alami, Nur Hidayatul; Kuswytasari, N. D.; Zulaikha, Enny

2017-06-01

Lately, plastic bag is becoming the most important pollutant for environment since it is difficult to be naturally degraded due to it consists of long hydrocarbon polymer chains. Our previous study indicated that our pure isolate Pseudomonas PL-01 and Bacillus PL-01 could degrade about 10% plastic bag. This present study was aimed to find out whether Pseudomonas PL01 and Bacillus PL01 put a positive effect to indigenous bacteria from marginal area in doing plastic degradation with a soil burial method. Beach sand was used as a representative marginal area, and mangrove sediment was used as a comparison. Plastics were submerged into unsterile beach sand with 10% of Pseudomonas PL-01 or Bacillus PL-01 containing liquid minimal salt medium (MSM) separately, while other plastics were submerged into unsterile mangrove sediments. After 4, 8, 12 and 16 weeks, their biofilm formation on their plastic surfaces and plastic degradation were measured. Results indicated that those 2 isolates put positive influent on biofilm formation and plastic degradation for indigenous beach sand bacteria. Bacillus PL-01 put higher influent than Pseudomonas PL-01. Plastic transparent was preferable degraded than black and white plastic bag `kresek'. But anyhow, indigenous mangrove soil bacteria showed the best performance in biofilm formation and plastic degradation, even without Pseudomonas PL-01 or Bacillus PL-01 addition. Fourier Transform Infrared (FTIR) analysis complemented the results; there were attenuated peaks with decreasing peaks transmittances. This FTIR peaks indicated chemical functional group changes happened among the plastic compounds after 16 weeks incubation time.

Exploration of indigenous bacteria in an intensive aquaculture system of African catfish (Clarias sp.) in Banyuwangi, Indonesia

Science.gov (United States)

Prayogo; Rahardja, B. S.; Asshanti, A. N.; Dewi, N. N.; Santanumurti, M. B.

2018-04-01

Intensive African catfish culture in tarpaulin pond was popular in Banyuwangi, Indonesia since the government supported the fisheries sector. Unfortunately, the failure of African catfish culture still occurred since the waste from fish metabolite process and feed residue decreased the water quality. Bacteria in the water could be the solution to increase the success rate of aquaculture by improving the water quality. This study purpose was to obtained indigenous bacteria in intensive aquaculture system of African catfish to improve water quality. This study successfully isolated bacteria contained with amylase, protease and lipase characteristic. Isolated bacteria in this study were identified as Pseudomonas pseudomallei (97.81%), Bacillus subtilis (95.81%) and Pseudomonas stutzeri (61.21%).

Investigation of Acidithiobacillus ferrooxidans in pure and mixed-species culture for bioleaching of Theisen sludge from former copper smelting.

Science.gov (United States)

Klink, C; Eisen, S; Daus, B; Heim, J; Schlömann, M; Schopf, S

2016-06-01

The aim of this study was to investigate the potential of bioleaching for the treatment of an environmentally hazardous waste, a blast-furnace flue dust designated Theisen sludge. Bioleaching of Theisen sludge was investigated at acidic conditions with Acidithiobacillus ferrooxidans in pure and mixed-species culture with Acidiphilium. In shaking-flask experiments, bioleaching parameters (pH, redox potential, zinc extraction from ZnS, ferrous- and ferric-iron concentration) were controlled regularly. The analysis of the dissolved metals showed that 70% zinc and 45% copper were extracted. Investigations regarding the arsenic and antimony species were performed. When iron ions were lacking, animonate (Sb(V)) and total arsenic concentration were highest in solution. The bioleaching approach was scaled up in stirred-tank bioreactors resulting in higher leaching efficiency of valuable trace elements. Concentrations of dissolved antimony were approx. 23 times, and of cobalt, germanium, and rhenium three times higher in comparison to shaking-flask experiments, when considering the difference in solid load of Theisen sludge. The extraction of base and trace metals from Theisen sludge, despite of its high content of heavy metals and organic compounds, was feasible with iron-oxidizing acidophilic bacteria. In stirred-tank bioreactors, the mixed-species culture performed better. To the best of our knowledge, this study is the first providing an appropriate biological technology for the treatment of Theisen sludge to win valuable elements. © 2016 The Society for Applied Microbiology.

Omics on bioleaching: current and future impacts.

Science.gov (United States)

Martinez, Patricio; Vera, Mario; Bobadilla-Fazzini, Roberto A

2015-10-01

Bioleaching corresponds to the microbial-catalyzed process of conversion of insoluble metals into soluble forms. As an applied biotechnology globally used, it represents an extremely interesting field of research where omics techniques can be applied in terms of knowledge development, but moreover in terms of process design, control, and optimization. In this mini-review, the current state of genomics, proteomics, and metabolomics of bioleaching and the major impacts of these analytical methods at industrial scale are highlighted. In summary, genomics has been essential in the determination of the biodiversity of leaching processes and for development of conceptual and functional metabolic models. Proteomic impacts are mostly related to microbe-mineral interaction analysis, including copper resistance and biofilm formation. Early steps of metabolomics in the field of bioleaching have shown a significant potential for the use of metabolites as industrial biomarkers. Development directions are given in order to enhance the future impacts of the omics in biohydrometallurgy.

Bacteria heap leaching test of a uranium ore

International Nuclear Information System (INIS)

Liu Hui; Liu Jinhui; Wu Weirong; Han Wei

2008-01-01

Column bioleaching test of a uranium ore was carried out. The optimum acidity, spraying intensity, spray-pause time ratio were determined. The potential, Fe and U concentrations in the leaching process were investigated. The effect of bacteria column leaching was compared with that of acid column leaching. The results show that bacteria column leaching can shorten leaching cycle, and the leaching rate of uranium increases by 9.7%. (authors)

Current scenario of chalcopyrite bioleaching: a review on the recent advances to its heap-leach technology.

Science.gov (United States)

Panda, Sandeep; Akcil, Ata; Pradhan, Nilotpala; Deveci, Haci

2015-11-01

Chalcopyrite is the primary copper mineral used for production of copper metal. Today, as a result of rapid industrialization, there has been enormous demand to profitably process the low grade chalcopyrite and "dirty" concentrates through bioleaching. In the current scenario, heap bioleaching is the most advanced and preferred eco-friendly technology for processing of low grade, uneconomic/difficult-to-enrich ores for copper extraction. This paper reviews the current status of chalcopyrite bioleaching. Advanced information with the attempts made for understanding the diversity of bioleaching microorganisms; role of OMICs based research for future applications to industrial sectors and chemical/microbial aspects of chalcopyrite bioleaching is discussed. Additionally, the current progress made to overcome the problems of passivation as seen in chalcopyrite bioleaching systems have been conversed. Furthermore, advances in the designing of heap bioleaching plant along with microbial and environmental factors of importance have been reviewed with conclusions into the future prospects of chalcopyrite bioleaching. Copyright © 2015 Elsevier Ltd. All rights reserved.

Degradation and utilization of polycyclic aromatic hydrocarbons by indigenous soil bacteria

International Nuclear Information System (INIS)

Stetzenbach, L.D.A.

1986-01-01

The persistence of industrially derived polycyclic aromatic hydrocarbons in the subsurface may be significantly affected by the metabolism of soil bacteria. This study was conducted to determine the ability of indigenous soil bacteria to decrease the concentration of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, anthracene, and pyrene) and to utilize the compounds as a substrate for growth. Soil cores from petroleum contaminated and noncontaminated sites contained 10 5 -10 7 viable microorganisms per gram dryweight of soil. Gram negative rod-shaped bacteria predominated. Decreases in the concentration of the four polycyclic aromatic hydrocarbons were observed during incubation with bacterial isolates in aqueous suspension by the use of high performance liquid chromatography. Corresponding increases in bacterial numbers indicated utilization of the compounds as a carbon source. Soil samples from the contaminated sites contained greater numbers of bacteria utilizing anthracene and pyrene than soil samples from uncontaminated sites. Degradation rates of the four polycyclic aromatic hydrocarbons were related to the compound, its concentration, and the bacterium. Biodegradation of pyrene was positively correlated with the presence of oxygen. Pyrene was biodegraded by an Acinetobacter sp. under aerobic conditions but not under anaerobic or microaerophilic conditions. Studies with radiolabeled 14 C-anthracene demonstrated utilization of the labeled carbon as a source of carbon by viable bacterial cells in aqueous suspension. Incorporation of 14 C into cellular biomass however was not observed during incubation of 14 C-anthracene in soil

Effect of bioleaching on hydrogen-rich gas production by steam gasification of sewage sludge

International Nuclear Information System (INIS)

Li, Hanhui; Chen, Zhihua; Huo, Chan; Hu, Mian; Guo, Dabin; Xiao, Bo

2015-01-01

Highlights: • Bioleaching can modify the physicochemical property of sewage sludge. • The enhancement is mainly hydrogen. • Bioleaching can enhance the gas production in gasification of sewage sludge. • Study provides an insight for future application of bioleached sewage sludge. - Abstract: Effect of bioleaching on hydrogen-rich gas production by steam gasification of sewage sludge was carried out in a lab-scale fixed-bed reactor. The influence of sewage sludge solids concentrations (6–14% (w/v) in 2% increments) during the bioleaching process and reactor temperature (600–900 °C in 100 °C increments) on gasification product yields and gas composition were studied. Characterization of samples showed that bioleaching treatment, especially in 6% (w/v) sludge solids concentration, led to metal removal effectively and modifications in the physicochemical property of sewage sludge which was favored for gasification. The maximum gas yield (49.4%) and hydrogen content (46.4%) were obtained at 6% (w/v) sludge solids concentration and reactor temperature of 900 °C. Sewage sludge after the bioleaching treatment may be a feasible feedstock for hydrogen-rich gas product.

A New Heterotrophic Strain for Bioleaching of Low Grade Complex Copper Ore

Directory of Open Access Journals (Sweden)

Kaijian Hu

2016-02-01

Full Text Available A new heterotrophic strain, named Providencia sp. JAT-1, was isolated and used in bioleaching of low-grade complex copper ore. The strain uses sodium citrate as a carbon source and urea as a nitrogen source to produce ammonia. The optimal growth condition of the strain is 30 C, initial pH 8, sodium citrate 10 g/L and urea 20 g/L, under which the cell density and ammonia concentration in the medium reached a maximum of 4.83 × 108 cells/mL and 14 g/L, respectively. Ammonia produced by the strain is used as the main lixiviant in bioleaching. Bioleaching results revealed that higher strain growth led to a higher copper recovery, while higher pulp density will cause a greater inhibitory effect on strain growth and ammonia production. The copper extraction reached the highest value of 54.5% at the pulp density of 1%. Malachite, chrysocolla and chalcocite are easy to leach out in this bioleaching system while chalcopyrite is difficult. Results of comparative leaching experiments show that bioleaching using JAT-1 is superior to ammonia leaching at the same condition. The metabolites produced by the strain other than ammonia are also involved in bioleaching.

Bioleaching of heavy metal polluted sediment: influence of sediment properties. Pt. 2

Energy Technology Data Exchange (ETDEWEB)

Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, D-01062 Dresden (Germany); Zehnsdorf, A. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Umwelt- und Biotechnologisches Zentrum, Permoserstrasse 15, D-04318 Leipzig (Germany); Hoffmann, P.; Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany)

2006-08-15

A remediation process for heavy metal polluted sediment has previously been developed, in which the heavy metals are removed from the sediment by solid-bed bioleaching using sulfuric acid as a leaching agent arising from added elemental sulfur (S{sup 0}). This process has been engineered with Weisse Elster River sediment (dredged near Leipzig, Germany), as an example. Here, six heavy metal polluted sediments originating from various bodies of water in Germany were subjected to bioleaching to evaluate the applicability of the developed process on sediment of different nature: each sediment was mixed with 2 % S{sup 0}, suspended in water and then leached under identical conditions. The buffer characteristics of each sediment were mainly governed by its carbonate and Ca content, i.e., by its geological background, the redox potential and oxidation state depended on its pre-treatment (e.g., on land disposal), while the pH value was influenced by both. The added S{sup 0} was quickly oxidized by the indigenous microbes even in slightly alkaline sediment. The microbially generated H{sub 2}SO{sub 4} accumulated in the aqueous phase and was in part precipitated as gypsum. Significant acidification and heavy metal solubilization only occurred with sediment poor in buffer substances. With the exception of one sediment, the behavior in bioleaching correlated well with the behavior in titration with H{sub 2}SO{sub 4}. Since the content in carbonate seemed to be the most important factor deciding on the leachability of a sediment, oxic Weisse Elster River sediment was mixed with 2 % S{sup 0} and 0 to 100 g/kg of ground limestone to simulate various buffer capacities, suspended in water and then leached. The lime did not inhibit microbial S{sup 0} oxidation but generated a delay in acidification due to neutralization of formed H{sub 2}SO{sub 4}, where the pH only started to decrease when the lime was completely consumed. The more lime the sediment contained, the longer this lag

Indigenous opportunistic bacteria inhabit mammalian gut-associated lymphoid tissues and share a mucosal antibody-mediated symbiosis.

Science.gov (United States)

Obata, Takashi; Goto, Yoshiyuki; Kunisawa, Jun; Sato, Shintaro; Sakamoto, Mitsuo; Setoyama, Hiromi; Matsuki, Takahiro; Nonaka, Kazuhiko; Shibata, Naoko; Gohda, Masashi; Kagiyama, Yuki; Nochi, Tomonori; Yuki, Yoshikazu; Fukuyama, Yoshiko; Mukai, Akira; Shinzaki, Shinichiro; Fujihashi, Kohtaro; Sasakawa, Chihiro; Iijima, Hideki; Goto, Masatoshi; Umesaki, Yoshinori; Benno, Yoshimi; Kiyono, Hiroshi

2010-04-20

The indigenous bacteria create natural cohabitation niches together with mucosal Abs in the gastrointestinal (GI) tract. Here we report that opportunistic bacteria, largely Alcaligenes species, specifically inhabit host Peyer's patches (PPs) and isolated lymphoid follicles, with the associated preferential induction of antigen-specific mucosal IgA Abs in the GI tract. Alcaligenes were identified as the dominant bacteria on the interior of PPs from naïve, specific-pathogen-free but not from germ-free mice. Oral transfer of intratissue uncultured Alcaligenes into germ-free mice resulted in the presence of Alcaligenes inside the PPs of recipients. This result was further supported by the induction of antigen-specific Ab-producing cells in the mucosal (e.g., PPs) but not systemic compartment (e.g., spleen). The preferential presence of Alcaligenes inside PPs and the associated induction of intestinal secretory IgA Abs were also observed in both monkeys and humans. Localized mucosal Ab-mediated symbiotic immune responses were supported by Alcaligenes-stimulated CD11c(+) dendritic cells (DCs) producing the Ab-enhancing cytokines TGF-beta, B-cell-activating factor belonging to the TNF family, and IL-6 in PPs. These CD11c(+) DCs did not migrate beyond the draining mesenteric lymph nodes. In the absence of antigen-specific mucosal Abs, the presence of Alcaligenes in PPs was greatly diminished. Thus, indigenous opportunistic bacteria uniquely inhabit PPs, leading to PP-DCs-initiated, local antigen-specific Ab production; this may involve the creation of an optimal symbiotic environment on the interior of the PPs.

Genomic and metagenomic challenges and opportunities for bioleaching: a mini-review.

Science.gov (United States)

Cárdenas, Juan Pablo; Quatrini, Raquel; Holmes, David S

2016-09-01

High-throughput genomic technologies are accelerating progress in understanding the diversity of microbial life in many environments. Here we highlight advances in genomics and metagenomics of microorganisms from bioleaching heaps and related acidic mining environments. Bioleaching heaps used for copper recovery provide significant opportunities to study the processes and mechanisms underlying microbial successions and the influence of community composition on ecosystem functioning. Obtaining quantitative and process-level knowledge of these dynamics is pivotal for understanding how microorganisms contribute to the solubilization of copper for industrial recovery. Advances in DNA sequencing technology provide unprecedented opportunities to obtain information about the genomes of bioleaching microorganisms, allowing predictive models of metabolic potential and ecosystem-level interactions to be constructed. These approaches are enabling predictive phenotyping of organisms many of which are recalcitrant to genetic approaches or are unculturable. This mini-review describes current bioleaching genomic and metagenomic projects and addresses the use of genome information to: (i) build metabolic models; (ii) predict microbial interactions; (iii) estimate genetic diversity; and (iv) study microbial evolution. Key challenges and perspectives of bioleaching genomics/metagenomics are addressed. Copyright © 2016 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.

Draft genome sequence of chloride-tolerant Leptospirillum ferriphilum Sp-Cl from industrial bioleaching operations in northern Chile.

Science.gov (United States)

Issotta, Francisco; Galleguillos, Pedro A; Moya-Beltrán, Ana; Davis-Belmar, Carol S; Rautenbach, George; Covarrubias, Paulo C; Acosta, Mauricio; Ossandon, Francisco J; Contador, Yasna; Holmes, David S; Marín-Eliantonio, Sabrina; Quatrini, Raquel; Demergasso, Cecilia

2016-01-01

Leptospirillum ferriphilum Sp-Cl is a Gram negative, thermotolerant, curved, rod-shaped bacterium, isolated from an industrial bioleaching operation in northern Chile, where chalcocite is the major copper mineral and copper hydroxychloride atacamite is present in variable proportions in the ore. This strain has unique features as compared to the other members of the species, namely resistance to elevated concentrations of chloride, sulfate and metals. Basic microbiological features and genomic properties of this biotechnologically relevant strain are described in this work. The 2,475,669 bp draft genome is arranged into 74 scaffolds of 74 contigs. A total of 48 RNA genes and 2,834 protein coding genes were predicted from its annotation; 55 % of these were assigned a putative function. Release of the genome sequence of this strain will provide further understanding of the mechanisms used by acidophilic bacteria to endure high osmotic stress and high chloride levels and of the role of chloride-tolerant iron-oxidizers in industrial bioleaching operations.

Effects of pyrite and sphalerite on population compositions, dynamics and copper extraction efficiency in chalcopyrite bioleaching process.

Science.gov (United States)

Xiao, Yunhua; Liu, Xueduan; Dong, Weiling; Liang, Yili; Niu, Jiaojiao; Gu, Yabing; Ma, Liyuan; Hao, Xiaodong; Zhang, Xian; Xu, Zhen; Yin, Huaqun

2017-07-01

This study used an artificial microbial community with four known moderately thermophilic acidophiles (three bacteria including Acidithiobacillus caldus S1, Sulfobacillus thermosulfidooxidans ST and Leptospirillum ferriphilum YSK, and one archaea, Ferroplasma thermophilum L1) to explore the variation of microbial community structure, composition, dynamics and function (e.g., copper extraction efficiency) in chalcopyrite bioleaching (C) systems with additions of pyrite (CP) or sphalerite (CS). The community compositions and dynamics in the solution and on the ore surface were investigated by real-time quantitative PCR (qPCR). The results showed that the addition of pyrite or sphalerite changed the microbial community composition and dynamics dramatically during the chalcopyrite bioleaching process. For example, A. caldus (above 60%) was the dominant species at the initial stage in three groups, and at the middle stage, still dominated C group (above 70%), but it was replaced by L. ferriphilum (above 60%) in CP and CS groups; at the final stage, L. ferriphilum dominated C group, while F. thermophilum dominated CP group on the ore surface. Furthermore, the additions of pyrite or sphalerite both made the increase of redox potential (ORP) and the concentrations of Fe 3+ and H + , which would affect the microbial community compositions and copper extraction efficiency. Additionally, pyrite could enhance copper extraction efficiency (e.g., improving around 13.2% on day 6) during chalcopyrite bioleaching; on the contrary, sphalerite restrained it.

Bioleaching of rare earth elements from monazite sand.

Science.gov (United States)

Brisson, Vanessa L; Zhuang, Wei-Qin; Alvarez-Cohen, Lisa

2016-02-01

Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Paecilomyces spp. strain WE3-F. Although monazite also contains the radioactive element Thorium, bioleaching by these fungi preferentially solubilized rare earth elements over Thorium, leaving the Thorium in the solid residual. Adjustments in growth media composition improved bioleaching performance measured as rare earth release. Cell-free spent medium generated during growth of A. terreus strain ML3-1 and Paecilomyces spp. strain WE3-F in the presence of monazite leached rare earths to concentrations 1.7-3.8 times those of HCl solutions of comparable pH, indicating that compounds exogenously released by these organisms contribute substantially to leaching. Organic acids released by the organisms included acetic, citric, gluconic, itaconic, oxalic, and succinic acids. Abiotic leaching with laboratory prepared solutions of these acids was not as effective as bioleaching or leaching with cell-free spent medium at releasing rare earths from monazite, indicating that compounds other than the identified organic acids contribute to leaching performance. © 2015 Wiley Periodicals, Inc.

Impact of the microscale distribution of a Pseudomonas strain introduced into soil on potential contacts with indigenous bacteria

DEFF Research Database (Denmark)

Dechesne, Arnaud; Pallud, C.; Bertolla, F.

2005-01-01

Soil bioaugmentation is a promising approach in soil bioremediation and agriculture. Nevertheless, our knowledge of the fate and activity of introduced bacteria in soil and thus of their impact on the soil environment is still limited. The microscale spatial distribution of introduced bacteria has...... rarely been studied, although it determines the encounter probability between introduced cells and any components of the soil ecosystem and thus plays a role in the ecology of introduced bacteria. For example, conjugal gene transfer from introduced bacteria to indigenous bacteria requires cell......-to-cell contact, the probability of which depends on their spatial distribution. To quantitatively characterize the microscale distribution of an introduced bacterial population and its dynamics, a gfp-tagged derivative of Pseudomonas putida KT2440 was introduced by percolation in repacked soil columns. Initially...

Experiences and Future Challenges of Bioleaching Research in South Korea

Directory of Open Access Journals (Sweden)

Danilo Borja

2016-12-01

Full Text Available This article addresses the state of the art of bioleaching research published in South Korean Journals. Our research team reviewed the available articles registered in the Korean Citation Index (KCI, Korean Journal Database addressing the relevant aspects of bioleaching. We systematically categorized the target metal sources as follows: mine tailings, electronic waste, mineral ores and metal concentrates, spent catalysts, contaminated soil, and other materials. Molecular studies were also addressed in this review. The classification provided in the present manuscript details information about microbial species, parameters of operation (e.g., temperature, particle size, pH, and process length, and target metals to compare recoveries among the bioleaching processes. The findings show an increasing interest in the technology from research institutes and mineral processing-related companies over the last decade. The current research trends demonstrate that investigations are mainly focused on determining the optimum parameters of operations for different techniques and minor applications at the industrial scale, which opens the opportunity for greater technological developments. An overview of bioleaching of each metal substrate and opportunities for future research development are also included.

The Control of Microcystis spp. Bloom by Combining Indigenous Denitrifying Bacteria From Sutami Reservoir with Fimbristylis globulosa and Vetiveria zizanoides

Directory of Open Access Journals (Sweden)

Bayu Agung Prahardika

2013-04-01

Full Text Available The purpose of this research is to know the ability of polyculture macrophyte (Fimbristylis globulosa and Vetiveria zizanoides and the combination of both with consortium of indigenous denitrifying bacteria from Sutami reservoir that was added by Microcystis spp. or not to reduce the concentration of nitrate, dissolved phosphate and the carrying capacity of Microcystis spp. The experiment was done in a medium filled up with Sutami reservoir water enriched with 16 ppm of nitrate and 0.4 ppm of phosphate. The denitrifying bacteria used in this research were DR-14, DU-27-1, DU-30-1, DU-30-2, TA-8 and DU-27-4 isolated from Sutami reservoir. The treatments were incubated within 15 days. Microcystis spp. abundance was calculated every day, but the measurement of the concentration of nitrate and dissolved phosphate was done every six days. The results showed that both treatment and the combination of both macrophytes with a consortium of denitrifying indigenous bacteria were added or not either Microcystis able to reduce nitrate at 99% and 93-99% orthophosphoric. The combination of macrophytes with denitrifying indigenous bacterial consortium from Sutami reservoir was able to inhibit the carrying capacity of Microcystis spp. highest up to 47.87%. They could also significantly reduce the abundance of Microcystis from 107 cells/mL in earlier days of the treatment into 0.35x104 cells/mL after fifteen days of incubation.

Bioleaching combined brine leaching of heavy metals from lead-zinc mine tailings: Transformations during the leaching process.

Science.gov (United States)

Ye, Maoyou; Yan, Pingfang; Sun, Shuiyu; Han, Dajian; Xiao, Xiao; Zheng, Li; Huang, Shaosong; Chen, Yun; Zhuang, Shengwei

2017-02-01

During the process of bioleaching, lead (Pb) recovery is low. This low recovery is caused by a problem with the bioleaching technique. This research investigated the bioleaching combination of bioleaching with brine leaching to remove heavy metals from lead-zinc mine tailings. The impact of different parameters were studied, including the effects of initial pH (1.5-3.0) and solid concentration (5-20%) for bioleaching, and the effects of sodium chloride (NaCl) concentration (10-200 g/L) and temperature (25 and 50 °C) for brine leaching. Complementary characterization experiments (Sequential extraction, X-ray diffractometer (XRD), scanning electronic microscope (SEM)) were also conducted to explore the transformation of tailings during the leaching process. The results showed that bioleaching efficiency was significantly influenced by initial pH and solid concentration. Approximately 85.45% of iron (Fe), 4.12% of Pb, and 97.85% of zinc (Zn) were recovered through bioleaching in optimum conditions. Increasing the brine concentration and temperature promoted lead recovery. Lead was recovered from the bioleaching residues at a rate of 94.70% at 25 °C and at a rate of 99.46% at 50 °C when the NaCl concentration was 150 g/L. The study showed that bioleaching significantly changed the speciation of heavy metals and the formation and surface morphology of tailings. The metals were mainly bound in stable fractions after bioleaching. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioleaching of nickel from spent petroleum catalyst using Acidithiobacillus thiooxidans DSM- 11478.

Science.gov (United States)

Sharma, Mohita; Bisht, Varsha; Singh, Bina; Jain, Pratiksha; Mandal, Ajoy K; Lal, Banwari; Sarma, Priyangshu M

2015-06-01

The present work deals with optimization of culture conditions and process parameters for bioleaching of spent petroleum catalyst collected from a petroleum refinery. The efficacy of Ni bioleaching from spent petroleum catalyst was determined using pure culture of Acidithiobacillus thiooxidans DSM- 11478. The culture conditions of pH, temperature and headspace volume to media volume ratio were optimized. EDX analysis was done to confirm the presence of Ni in the spent catalyst after roasting it to decoke its surface. The optimum temperature for A. thiooxidans DSM-11478 growth was found to be 32 degrees C. The enhanced recovery of nickel at very low pH was attributed to the higher acidic strength of sulfuric acid produced in the culture medium by the bacterium. During the bioleaching process, 89% of the Ni present in the catalyst waste could be successfully recovered in optimized conditions. This environment friendly bioleaching process proved efficient than the chemical method. Taking leads from the lab scale results, bioleaching in larger volumes (1, 5 and 10 L) was also performed to provide guidelines for taking up this technology for in situ industrial waste management.

Arsenopyrite and pyrite bioleaching: evidence from XPS, XRD and ICP techniques.

Science.gov (United States)

Fantauzzi, Marzia; Licheri, Cristina; Atzei, Davide; Loi, Giovanni; Elsener, Bernhard; Rossi, Giovanni; Rossi, Antonella

2011-10-01

In this work, a multi-technical bulk and surface analytical approach was used to investigate the bioleaching of a pyrite and arsenopyrite flotation concentrate with a mixed microflora mainly consisting of Acidithiobacillus ferrooxidans. X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and X-ray-induced Auger electron spectroscopy mineral surfaces investigations, along with inductively coupled plasma-atomic emission spectroscopy and carbon, hydrogen, nitrogen and sulphur determination (CHNS) analyses, were carried out prior and after bioleaching. The flotation concentrate was a mixture of pyrite (FeS(2)) and arsenopyrite (FeAsS); after bioleaching, 95% of the initial content of pyrite and 85% of arsenopyrite were dissolved. The chemical state of the main elements (Fe, As and S) at the surface of the bioreactor feed particles and of the residue after bioleaching was investigated by X-ray photoelectron and X-ray excited Auger electron spectroscopy. After bioleaching, no signals of iron, arsenic and sulphur originating from pyrite and arsenopyrite were detected, confirming a strong oxidation and the dissolution of the particles. On the surfaces of the mineral residue particles, elemental sulphur as reaction intermediate of the leaching process and precipitated secondary phases (Fe-OOH and jarosite), together with adsorbed arsenates, was detected. Evidence of microbial cells adhesion at mineral surfaces was also produced: carbon and nitrogen were revealed by CHNS, and nitrogen was also detected on the bioleached surfaces by XPS. This was attributed to the deposition, on the mineral surfaces, of the remnants of a bio-film consisting of an extra-cellular polymer layer that had favoured the bacterial action. © Springer-Verlag 2011

Dynamic of active microorganisms inhabiting a bioleaching industrial heap of low‐grade copper sulfide ore monitored by real‐time PCR and oligonucleotide prokaryotic acidophile microarray

Science.gov (United States)

Remonsellez, Francisco; Galleguillos, Felipe; Moreno‐Paz, Mercedes; Parro, Víctor; Acosta, Mauricio; Demergasso, Cecilia

2009-01-01

Summary The bioleaching of metal sulfide has developed into a very important industrial process and understanding the microbial dynamic is key to advancing commercial bioleaching operations. Here we report the first quantitative description of the dynamic of active communities in an industrial bioleaching heap. Acidithiobacillus ferrooxidans was the most abundant during the first part of the leaching cycle, while the abundance of Leptospirillum ferriphilum and Ferroplasma acidiphilum increased with age of the heap. Acidithiobacillus thiooxidans kept constant throughout the leaching cycle, and Firmicutes group showed a low and a patchy distribution in the heap. The Acidiphilium‐like bacteria reached their highest abundance corresponding to the amount of autotrophs. The active microorganisms in the leaching system were determined using two RNA‐based sensitive techniques. In most cases, the 16S rRNA copy numbers of At. ferrooxidans, L. ferriphilum, At. thiooxidans and F. acidiphilum, was concomitant with the DNA copy numbers, whereas Acidiphilium‐like bacteria and some Firmicutes members did not show a clear correlation between 16S rRNA accumulation and DNA copy numbers. However, the prokaryotic acidophile microarray (PAM) analysis showed active members of Alphaproteobacteria in all samples and of Sulfobacillus genus in older ones. Also, new active groups such as Actinobacteria and Acidobacterium genus were detected by PAM. The results suggest that changes during the leaching cycle in chemical and physical conditions, such as pH and Fe3+/Fe2+ ion rate, are primary factors shaping the microbial dynamic in the heap. PMID:21255296

Continued Multicolumns Bioleaching for Low Grade Uranium Ore at a Certain Uranium Deposit

OpenAIRE

Gongxin Chen; Zhanxue Sun; Yajie Liu

2016-01-01

Bioleaching has lots of advantages compared with traditional heap leaching. In industry, bioleaching of uranium is still facing many problems such as site space, high cost of production, and limited industrial facilities. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains high fluoride. The analysis of chemical composition of ore shows that the grade of uranium is 0.208%, which is lower than that of other deposits. Howev...

The transformation from anammox granules to deammonification granules in micro-aerobic system by facilitating indigenous ammonia oxidizing bacteria.

Science.gov (United States)

Wang, Xiaolong; Gao, Dawen

2018-02-01

Granular deammonification process is a good way to retain aerobic and anaerobic ammonia oxidizing bacteria (AOB and anammox bacteria) and exhaust flocculent nitrite oxidizing bacteria (NOB). In this study, to facilitate indigenous AOB growth on anammox granules, by stepwise reducing influent nitrite, anammox granules were effectively transformed into deammonification granules in a micro-aerobic EGSB in 100 days. Total nitrogen removal efficiency of 90% and nitrogen removal rate of 2.3 g N/L/d were reached at stable deammonification stage. High influent FA and limited oxygen supply contributed suppression for Nitrospira-like NOB. In transition stages, Proteobacteria and Chloroflexi were always dominated. Anammox abundance decreased, while AOB abundance grew fast. Anammox bacteria and AOB were dominated by Brocadia fulgida and Nitrosomonas europaea, respectively. Denitrification activity and bacteria existed although without influent organic. The final AOB abundance was about 4.55-13.8 times more than anammox bacteria abundance, with almost equal potential activities. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of heterotrophic microorganism Galactomyces sp. Z3 in improving pig slurry bioleaching.

Science.gov (United States)

Zhou, Jun; Zheng, Guanyu; Zhou, Lixiang; Liu, Fenwu; Zheng, Chaocheng; Cui, Chunhong

2013-01-01

The feasibility of removing heavy metals and eliminating pathogens from pig slurry through bioleaching involving the fungus Galactomyces sp. Z3 and two acidophilic thiobacillus (A. ferrooxidans LX5 and A. thiooxidans TS6) was investigated. It was found that the isolated pig slurry dissolved organic matter (DOM) degrader Z3 was identified as Galactomyces sp. Z3, which could grow well at pH 2.5-7 and degrade pig slurry DOM from 1973 to 942 mg/l within 48 h. During the successive multi-batch bioleaching systems, the co-inoculation of pig slurry degrader Galactomyces sp. Z3 and the two Acidithiobacillus species could improve pig slurry bioleaching efficiency compared to the single system without Galactomyces sp. Z3. The removal efficiency of Zn and Cu exceeded 94% and 85%, respectively. In addition, the elimination efficiencies of pathogens, including both total coliform and faecal coliform counts, exceeded 99% after bioleaching treatment. However, the counts of Galactomyces sp. Z3 decreased with the fall of pH and did not restore to the initial level during successive multi-batch bioleaching systems, and it is necessary to re-inoculate Galactomyces sp. Z3 cells into the bioleaching system to maintain its role in degrading pig slurry DOM. Therefore, a bioleaching technique involving both Galactomyces sp. Z3 and Acidithiobacillus species is an efficient method for removing heavy metals and eliminating pathogens from pig slurry.

Improvement of sludge dewaterability and removal of sludge-borne metals by bioleaching at optimum pH.

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Liu, Fenwu; Zhou, Lixiang; Zhou, Jun; Song, Xingwei; Wang, Dianzhan

2012-06-30

Bio-acidification caused by bio-oxidation of energy substances during bioleaching is widely known to play an important role in improving sludge-borne metals removal. Here we report that bioleaching also drastically enhances sludge dewaterability in a suitable pH level. To obtain the optimum initial concentrations of energy substances and pH values for sludge dewaterability during bioleaching, bio-oxidation of Fe(2+) and S(0) under co-inoculation with Acidithiobacillus thiooxidans TS6 and Acidothiobacillus ferrooxidans LX5 and their effects on sludge dewaterability and metals removal during sludge bioleaching were investigated. Results indicated that the dosage of energy substances with 2g/L S(0) and 2g/L Fe(2+) could obtain bio-oxidation efficiencies of up to 100% for Fe(2+) and 50% for S(0) and were the optimal dosages for sludge bioleaching. The removal efficiencies of sludge-borne Cu and Cr could reach above 85% and 40%, respectively, and capillary suction time (CST) of bioleached sludge decreased to as low as ∼10s from initial 48.9s for fresh sludge when sludge pH declined to ∼2.4 through bioleaching. These results confirm the potential of bioleaching as a novel method for improving sludge dewaterability as well as removal of metals. Copyright © 2012 Elsevier B.V. All rights reserved.

Co-Bioleaching of Chalcopyrite and Silver-Bearing Bornite in a Mixed Moderately Thermophilic Culture

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Congren Yang

2017-12-01

Full Text Available Chalcopyrite and bornite are two important copper minerals, and they often coexist. In this study, the co-bioleaching of chalcopyrite and silver-bearing bornite by mixed moderately thermophilic culture at 50 °C was investigated. The bioleaching results show that the extraction percentage of Cu for co-bioleaching of chalcopyrite (Ccp and silver-bearing bornite (Bn (Ccp/Bn = 3:1 was 94.6%. Compared to bioleaching of chalcopyrite or silver-bearing bornite alone, the Cu extraction percentage was greatly enhanced when they were bioleached together. The leaching residues were characterized by X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS. Silver-bearing bornite dissolved preferentially compared to chalcopyrite, due to galvanic interactions. Simultaneously, Ag+ was released from the silver-bearing bornite into solution. Ag2S formed on the surface because Cu and Fe in the chalcopyrite were replaced by Ag+, accelerating chalcopyrite dissolution and enrichment of Ag on the surface of the chalcopyrite.

Evolution of Sulfobacillus thermosulfidooxidans secreting alginate during bioleaching of chalcopyrite concentrate.

Science.gov (United States)

Yu, R-L; Liu, A; Liu, Y; Yu, Z; Peng, T; Wu, X; Shen, L; Liu, Y; Li, J; Liu, X; Qiu, G; Chen, M; Zeng, W

2017-06-01

To explore the distribution disciplinarian of alginate on the chalcopyrite concentrate surface during bioleaching. The evolution of Sulfobacillus thermosulfidooxidans secreting alginate during bioleaching of chalcopyrite concentrate was investigated through gas chromatography coupled with mass spectrometry (GC-MS) and confocal laser scanning microscope (CLSM), and the critical synthetic genes (algA, algC, algD) of alginate were analysed by real-time polymerase chain reaction (RT-PCR). The GC-MS analysis results indicated that there was a little amount of alginate formed on the mineral surface at the early stage, while increasing largely to the maximum value at the intermediate stage, and then kept a stable value at the end stage. The CLSM analysis of chalcopyrite slice showed the same variation trend of alginate content on the mineral surface. Furthermore, the RT-PCR results showed that during the early stage of bioleaching, the expressions of the algA, algC and the algD genes were all overexpressed. However, at the final stage, the algD gene expression decreased in a large scale, and the algA and algC decreased slightly. This expression pattern was attributed to the fact that algA and algC genes were involved in several biosynthesis reactions, but the algD gene only participated in the alginate biosynthesis and this was considered as the key gene to control alginate synthesis. The content of alginate on the mineral surface increased largely at the beginning of bioleaching, and remained stable at the end of bioleaching due to the restriction of algD gene expression. Our findings provide valuable information to explore the relationship between alginate formation and bioleaching of chalcopyrite. © 2017 The Society for Applied Microbiology.

Saline-water bioleaching of chalcopyrite with thermophilic, iron(II)- and sulfur-oxidizing microorganisms.

Science.gov (United States)

Watling, Helen R; Collinson, David M; Corbett, Melissa K; Shiers, Denis W; Kaksonen, Anna H; Watkin, Elizabeth L J

2016-09-01

The application of thermoacidophiles for chalcopyrite (CuFeS2) bioleaching in hot, acidic, saline solution was investigated as a possible process route for rapid Cu extraction. The study comprised a discussion of protective mechanisms employed for the survival and/or adaptation of thermoacidophiles to osmotic stress, a compilation of chloride tolerances for three genera of thermoacidophiles applied in bioleaching and an experimental study of the activities of three species in a saline bioleaching system. The data showed that the oxidation rates of iron(II) and reduced inorganic sulfur compounds (tetrathionate) were reduced in the presence of chloride levels well below chloride concentrations in seawater, limiting the applicability of these microorganisms in the bioleaching of CuFeS2 in saline water. Copyright © 2016. Published by Elsevier Masson SAS.

Bioleaching of multiple heavy metals from contaminated sediment by mesophile consortium.

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Gan, Min; Zhou, Shuang; Li, Mingming; Zhu, Jianyu; Liu, Xinxing; Chai, Liyuan

2015-04-01

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.

Lead pollution in a large, prairie-pothole lake (Rush Lake, WI, USA): Effects on abundance and community structure of indigenous sediment bacteria

International Nuclear Information System (INIS)

Grandlic, Christopher J.; Geib, Ian; Pilon, Renee; Sandrin, Todd R.

2006-01-01

Rush Lake (WI, USA), the largest prairie-pothole lake east of the Mississippi River, has been contaminated with lead pollution as a result of over 140 years of waterfowl hunting. We examined: (1) the extent of lead pollution in Rush Lake sediments and (2) whether lead pollution in Rush Lake is affecting the abundance and community structure of indigenous sediment bacteria. Sediment lead concentrations did not exceed 59 mg Pb kg -1 dry sediment. No relationship was observed between sediment lead concentration and the abundance of aerobic (P = 0.498) or anaerobic (P = 0.416) heterotrophic bacteria. Similarly, lead did not appear to affect bacterial community structure when considering both culturable and nonculturable community members. In contrast, the culturable fraction of sediment bacteria in samples containing 59 mg Pb kg -1 exhibited a unique community structure. While factors other than lead content likely play roles in determining bacterial community structure in the sediments of Rush Lake, these data suggest that the culturable fraction of sediment bacterial communities is affected by elevated lead levels. - Low levels of lead pollution in Rush Lake are not impinging upon the abundance of indigenous sediment bacteria, but may be affecting the community structure of the culturable fraction of these bacteria

Kinetics of Petroleum-Contaminated Soil Biodegraded by An Indigenous Bacteria Bacillus megaterium

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BAMBANG YUDONO

2010-12-01

Full Text Available Bioremediation of petroleum sludge was conducted by using land-farming method in micro scale and by applying an indigenous bacteria Bacillus megaterium The samples were from PT. Pertamina Musi Banyuasin district of South Sumatra. The research aim was to evaluate the performance of the bacteria in degrading petroleum sludge. The rate of the biodegradation process was determined by using differential method and the data analyses show that the reaction order is 0.74. Then, the rate of biodegradation constant was determined by using an integral method assuming that the biodegradation process was a first reaction order. From the calculation, it was revealed that the biodegradation reaction constant was 0.0204/day. The bioremediation-kinetics model is y = −0.0204X + 2.0365, and by using this model the bioremediation process could be ended after 99.83 days. The qualitative analysis was carried out by using GC-MS to investigate the components of compounds changed during the bioremediation process. The results show that the B. megaterium could degrade 99.32% of alkane compounds.

Bioleaching of copper from old flotation tailings samples (Copper Mine Bor, Serbia

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Stanković Srđan

2015-01-01

Full Text Available Bioleaching of samples taken from depths of 10, 15, and 20 meters from old flotation tailings of the Copper Mine Bor was conducted in shaken flasks using extremely acidic water of Lake Robuleas lixiviant. Yield of copper after five weeks of the bioleaching experiment was 68.34±1.21% for 15 m sample, 72.57±0.57% for 20 m sample and 97.78±5.50% for 10 m sample. The obtained results were compared to the results of acid leaching of the same samples and it was concluded that bioleaching was generally more efficient for the treatment of samples taken from depths of 10 m and 20 m. The content of pyrite in the 20 m sample, which contained the highest amount of this mineral, was reduced after bioleaching. Benefits of this approach are: recovery of substantial amounts of copper, reducing the environmental impact of flotation tailings and the application of abundant and free water from the Robule acidic lake as lixiviant. Results of the experiment showed that bioleaching can be more efficient than acid leaching for copper extraction from flotation tailings with higher sulfide contents. [Projekat Ministarstva nauke Republike Srbije, br. 176016 i br. 173048

Effects of activated carbon on reductive dechlorination of PCBs by organohalide respiring bacteria indigenous to sediments.

Science.gov (United States)

Kjellerup, B V; Naff, C; Edwards, S J; Ghosh, U; Baker, J E; Sowers, K R

2014-04-01

Polychlorinated biphenyls (PCBs) have accumulated in aquatic sediments due to their inherent chemical stability and their presence poses a risk due to their potential toxicity in humans and animals. Granular activated carbon (GAC) has been applied to PCB contaminated sediment sites to reduce the aqueous concentration by sequestration thus reducing the PCB exposure and toxicity to both benthic and aquatic organisms. However, it is not known how the reduction of PCB bioavailability by adsorption to GAC affects bacterial transformation of PCBs by indigenous organohalide respiring bacteria. In this study, the impact of GAC on anaerobic dechlorination by putative organohalide respiring bacteria indigenous to sediment from Baltimore Harbor was examined. It was shown that the average Cl/biphenyl after dehalogenation of Aroclor 1260 was similar between treatments with and without GAC amendment. However, GAC caused a substantial shift in the congener distribution whereby a smaller fraction of highly chlorinated congeners was more extensively dechlorinated to mono- through tri-chlorinated congeners compared to the formation of tri- through penta-chlorinated congeners in unamended sediment. The results combined with comparative sequence analysis of 16S rRNA gene sequences suggest that GAC caused a community shift to putative organohalide respiring phylotypes that coincided with more extensive dechlorination of ortho and unflanked chlorines. This shift in activity by GAC shown here for the first time has the potential to promote greater degradation in situ by promoting accumulation of less chlorinated congeners that are generally more susceptible to complete mineralization by aerobic PCB degrading bacteria. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synergistic bioleaching of chalcopyrite and bornite in the presence of Acidithiobacillus ferrooxidans.

Science.gov (United States)

Zhao, Hongbo; Wang, Jun; Hu, Minghao; Qin, Wenqing; Zhang, Yansheng; Qiu, Guanzhou

2013-12-01

Bioleaching of chalcopyrite and bornite in the presence of Acidithiobacillus ferrooxidans was carried out to investigate the influences between each other during bioleaching. Bioleaching results indicated that bornite accelerated the dissolution of chalcopyrite, and chalcopyrite also accelerated the dissolution of bornite, it could be described as a synergistic effect during bioleaching, this synergistic effect might be attributed to the galvanic effect between chalcopyrite and bornite, and to the relatively low solution potential as the addition of bornite. Significantly amount of elemental sulfur and jarosite formed on the minerals surface might be the main passivation film inhibiting the further dissolution, and the amount of elemental sulfur significantly increased with the addition of bornite. Results of electrochemical measurements indicated that the oxidation and reduction mechanisms of chalcopyrite and bornite were similar, the addition of bornite or chalcopyrite did not change the oxidative and reductive mechanisms, but increased the oxidation rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of bioleaching on the mechanical and chemical properties of waste rocks

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Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

2012-01-01

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride.

Science.gov (United States)

Wang, Buyun; Wang, Kai

2013-05-01

A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].

Science.gov (United States)

Liu, Fen-Wu; Zhou, Li-Xiang; Zhou, Jun; Jiang, Feng; Wang, Dian-Zhan

2011-07-01

To observe the bioleaching effect on sewage sludge dewaterability, three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume. Subsequently, the bioleached sludge was dewatered by using chamber filter press. The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1: 15 mixing ratio of bioleached sludge to raw sludge. The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial -134 mV to finial 507 mV. The specific resistance to filtration (SRF) of the tested sludge was decreased from original 1.00 x 10(13) m/kg to final 0.09 x 10(13) m/kg after bioleaching. For the subsequent two batch trials, the bioleaching process can be finished in 40 hours and 46 hours, respectively. Likewise, sludge SRF is also significantly decreased to 0.19 x 10(13) m/kg and 0.36 x 10(13) m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1:1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd, and 3rd batch experiments, respectively. The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours. It is found that the moisture of dewatered sludge cake can be reduced to 58%, and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor. In addition, it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%, but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process. Therefore, dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above. Therefore, bioleaching technique is of great engineering application for the treatment of sewage sludge.

Heap bioleaching of uranium from low-grade granite-type ore by mixed acidophilic microbes

International Nuclear Information System (INIS)

Xuegang Wang; Zhongkui Zhou

2017-01-01

We evaluated uranium bioleaching from low-grade, granite-type uranium ore using mixed acidophilic microbes from uranium mine leachate. A 4854-ton plant-scale heap bioleaching process achieved sustained leaching with a uranium leaching efficiency of 88.3% using a pH of 1.0-2.0 and an Fe"3"+ dosage of 3.0-5.5 g/L. Acid consumption amounted to 25.8 g H_2SO_4 kg"-"1 ore. Uranium bioleaching follows a diffusion-controlled kinetic model with a correlation coefficient of 0.9136. Almost all uranium was dissolved in aqueous solution, except those encapsulated in quartz particles. Therefore, heap bioleaching by mixed acidophilic microbes enables efficient, economical, large-scale recovery of uranium from low-grade ores. (author)

Bioleaching of valuable metals from spent lithium-ion mobile phone batteries using Aspergillus niger

Science.gov (United States)

Horeh, N. Bahaloo; Mousavi, S. M.; Shojaosadati, S. A.

2016-07-01

In this paper, a bio-hydrometallurgical route based on fungal activity of Aspergillus niger was evaluated for the detoxification and recovery of Cu, Li, Mn, Al, Co and Ni metals from spent lithium-ion phone mobile batteries under various conditions (one-step, two-step and spent medium bioleaching). The maximum recovery efficiency of 100% for Cu, 95% for Li, 70% for Mn, 65% for Al, 45% for Co, and 38% for Ni was obtained at a pulp density of 1% in spent medium bioleaching. The HPLC results indicated that citric acid in comparison with other detected organic acids (gluconic, oxalic and malic acid) had an important role in the effectiveness of bioleaching using A. niger. The results of FTIR, XRD and FE-SEM analysis of battery powder before and after bioleaching process confirmed that the fungal activities were quite effective. In addition, bioleaching achieved higher removal efficiency for heavy metals than the chemical leaching. This research demonstrated the great potential of bio-hydrometallurgical route to recover heavy metals from spent lithium-ion mobile phone batteries.

Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching.

Science.gov (United States)

Zheng, Guanyu; Zhou, Lixiang

2011-10-15

Four inorganic mineral nutrients including NH4+, K+, Mg2+ and soluble inorganic phosphate (Pi) were investigated to reveal the potential limiting nutrients for tannery sludge bioleaching process driven by Acidithiobacillus species, and the feasibility of supplementing the limiting nutrients to accelerate tannery sludge bioleaching was studied in the present study. It was found that the concentration of Pi was lower than 3.5 mg/L throughout the whole bioleaching process, which is the most probable restricting nutrient for tannery sludge bioleaching. Further experiments revealed that the deficiency of Pi could seriously influence the growth of Acidithiobacillus thiooxidans and lower its oxidization capacity for S0, and the limiting concentration of Pi for the growth of A. thiooxidans was 6 mg/L. The low concentration of soluble Pi in sludge matrix was resulted from the extremely strong sorbing/binding capacity of tannery sludge for phosphate. The supplementation of more than 1.6 g/L KH2PO4 into tannery sludge bioleaching system could effectively stimulate the growth of Acidithiobacillus species, enhance Cr removal rate and further shorten tannery sludge bioleaching period from 10 days to 7 days. Therefore, inorganic phosphate supplementation is an effective and feasible method to accelerate tannery sludge bioleaching process, and the optimum dosage of KH2PO4 was 1.6 g/L for tannery sludge with 5.1% of total solids. Copyright © 2011 Elsevier Ltd. All rights reserved.

Feasibility of bioleaching combined with Fenton oxidation to improve sewage sludge dewaterability.

Science.gov (United States)

Liu, Changgeng; Zhang, Panyue; Zeng, Chenghua; Zeng, Guangming; Xu, Guoyin; Huang, Yi

2015-02-01

A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration (SRF) and moisture of sludge cake (MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge pH dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation. Meanwhile, the SRF declined from 6.45×10(10) to 2.07×10(10) s2/g, and MSC decreased from 91.42% to 87.66%. The bioleached sludge was further conditioned with Fenton oxidation. From an economical point of view, the optimal dosages of H2O2 and Fe2+ were 0.12 and 0.036 mol/L, respectively, and the optimal reaction time was 60 min. Under optimal conditions, SRF, volatile solids reduction, and MSC were 3.43×10(8) s2/g, 36.93%, and 79.58%, respectively. The stability and settleability of sewage sludge were both improved significantly. Besides, the results indicated that bioleaching-Fenton oxidation was more efficient in dewatering the sewage sludge than traditional Fenton oxidation. The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances-bound water and intercellular water. Copyright © 2014. Published by Elsevier B.V.

Separation of Metals From Spent Catalysts Waste by Bioleaching Process

OpenAIRE

Sirin Fairus, Tria Liliandini, M.Febrian, Ronny Kurniawan

2010-01-01

A kind of waste that hard to be treated is a metal containing solid waste. Leaching method is one thealternative waste treatment. But there still left an obstacle on this method, it is the difficulty to find theselective solvent for the type of certain metal that will separated. Bioleaching is one of the carry ablealternative waste treatments to overcome that obstacle. Bioleaching is a metal dissolving process orextraction from a sediment become dissolve form using microorganisms. On this met...

Genotypic characterization and safety assessment of lactic acid bacteria from indigenous African fermented food products

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Adimpong David B

2012-05-01

Full Text Available Abstract Background Indigenous fermented food products play an essential role in the diet of millions of Africans. Lactic acid bacteria (LAB are among the predominant microbial species in African indigenous fermented food products and are used for different applications in the food and biotechnology industries. Numerous studies have described antimicrobial susceptibility profiles of LAB from different parts of the world. However, there is limited information on antimicrobial resistance profiles of LAB from Africa. The aim of this study was to characterize 33 LAB previously isolated from three different African indigenous fermented food products using (GTG5-based rep-PCR, sequencing of the 16S rRNA gene and species-specific PCR techniques for differentiation of closely related species and further evaluate their antibiotic resistance profiles by the broth microdilution method and their haemolytic activity on sheep blood agar plates as indicators of safety traits among these bacteria. Results Using molecular biology based methods and selected phenotypic tests such as catalase reaction, CO2 production from glucose, colonies and cells morphology, the isolates were identified as Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus ghanensis, Lactobacillus plantarum, Lactobacillus salivarius, Leuconostoc pseudomesenteroides, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella confusa. The bacteria were susceptible to ampicillin, chloramphenicol, clindamycin and erythromycin but resistant to vancomycin, kanamycin and streptomycin. Variable sensitivity profiles to tetracycline and gentamicin was observed among the isolates with Lb. plantarum, Lb. salivarius, W. confusa (except strain SK9-5 and Lb. fermentum strains being susceptible to tetracycline whereas Pediococcus strains and Lb. ghanensis strains were resistant. For gentamicin, Leuc. pseudomesenteroides, Lb. ghanensis and Ped. acidilactici strains were resistant to 64�

Statistical optimization of gold recovery from difficult leachable sulphide minerals using bacteria

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Hussin A.M. [King Abdulaziz Univ., Jeddah (Saudi Arabia). Mining Engineering Dept.; El-Midany, Ayman A. [King Saud Univ., Riyadh (Saudi Arabia)

2012-07-01

Some of refractory gold ores represent one of the difficult processable ores due to fine dissemination and interlocking of the gold grains with the associated sulphide minerals. This makes it impossible to recover precious metals from sulphide matrices by direct cyanide leaching even at high consumption of cyanide solution. Research to solve this problem is numerous. Application of bacteria shows that, some types of bacteria have great affect on sulphides bio-oxidation and consequently facilitate the leaching process. In this paper, leaching of Saudi gold ore, from Alhura area, containing sulphides before cyanidation is studied to recover gold from such ores applying bacteria. The process is investigated using stirred reactor bio-leaching rather than heap bio-leaching. Using statistical analysis the main affecting variables under studied conditions were identified. The design results indicated that the dose of bacteria, retention time and nutrition K{sub 2}SO{sub 4} are the most significant parameters. The higher the bacterial dose and the bacterial nutrition, the better is the concentrate grade. Results show that the method is technically effective in gold recovery. A gold concentrate containing > 100 g/t gold was obtained at optimum conditions, from an ore containing < 2 g/t gold i.e., 10 ml bacterial dose, 6 days retention time, and 6.5 kg/t K{sub 2}SO{sub 4}as bacteria nutrition. (orig.)

Catalytic effect of light illumination on bioleaching of chalcopyrite.

Science.gov (United States)

Zhou, Shuang; Gan, Min; Zhu, Jianyu; Li, Qian; Jie, Shiqi; Yang, Baojun; Liu, Xueduan

2015-04-01

The influence of visible light exposure on chalcopyrite bioleaching was investigated using Acidithiobacillus ferrooxidans. The results indicated, in both shake-flasks and aerated reactors with 8500-lux light, the dissolved Cu was 91.80% and 23.71% higher, respectively, than that in the controls without light. The catalytic effect was found to increase bioleaching to a certain limit, then plateaued as the initial chalcopyrite concentration increased from 2% to 4.5%. Thus a balanced mineral concentration is highly amenable to bioleaching via offering increased available active sites for light adsorption while eschewing mineral aggregation and screening effects. Using semiconducting chalcopyrite, the light facilitated the reduction of Fe(3+) to Fe(2+) as metabolic substrates for A.ferrooxidans, leading to better biomass, lower pH and redox potential, which are conducive to chalcopyrite leaching. The light exposure on iron redox cycling was further confirmed by chemical leaching tests using Fe(3+), which exhibited higher Fe(2+) levels in the light-induced system. Copyright © 2015 Elsevier Ltd. All rights reserved.

The concomitant use of indigenous soil bacteria and fungi to enhance the bioremediation of refinery waste

Energy Technology Data Exchange (ETDEWEB)

Campos Carvalho, F.J.P. de [Universidade Federal do Parana, Curitiba (Brazil)

2001-07-01

Usually, the use of indigenous soil bacteria for the remediation of petroleum-contaminated soils was restricted to the biodegradation of low-molecular weight petroleum hydrocarbons such as gasoline, diesel, fuel oil and jet fuel. The advantage of using indigenous microorganisms is the minimization of the impact of the treatment on the microbial diversity. As a rule,these techniques are also well accepted by the public. Other studies have shown that fungi is successful for the bioremediation of heavier-weight contaminants. The concomitant transformation of low-molecular weight and heavier recalcitrant oil fractions to inorganic and humic form can be accomplished with the concomitant action of bacteria and fungi. The development of a soil biotreatment program using this concomitant technique was performed by PETROBRAS Petroleo Brasileiro S.A. - Refinaria Presidente Getulio Vargas in conjunction with the Universidade Federal do Parana. It resulted in a full-scale technology that allows the degradation of oil waste. Approximately two years of treatment are required to achieve the desired results. The use of standard analytical methods and bioindicators used on the treated soil indicated that the treated soil met the standards for agricultural soil quality. A recent oil spill occurred in Araucaria, Brazil and a bioremediation area was inoculated, and to date the results prove the beneficial effects to be derived from the use of inoculation. Some results were presented in table format. 3 tabs.

Recycling of spent nickel-cadmium batteries based on bioleaching process

International Nuclear Information System (INIS)

Zhu Nanwen; Zhang Lehua; Li Chunjie; Cai Chunguang

2003-01-01

Only 1-2 percent of discarded dry batteries are recovered in China. It is necessary to find an economic and environmentally friendly process to recycle dry batteries in this developing country. Bioleaching is one of the few techniques applicable for the recovery of the toxic metals from hazardous spent batteries. Its principle is the microbial production of sulphuric acid and simultaneous leaching of metals. In this study, a system consisting of a bioreactor, settling tank and leaching reactor was developed to leach metals from nickel-cadmium batteries. Indigenous thiobacilli, proliferated by using nutritive elements in sewage sludge and elemental sulphur as substrates, was employed in the bioreactor to produce sulphuric acid. The overflow from the bioreactor was conducted into the settling tank. The supernatant in the settling tank was conducted into the leaching reactor, which contained the anode and cathodic electrodes obtained from nickel-cadmium batteries. The results showed that this system was valid to leach metals from nickel-cadmium batteries, and that the sludge drained from the bottom of the settling tank could satisfy the requirements of environmental protection agencies regarding agricultural use

Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge.

Science.gov (United States)

Zhu, Yi; Zeng, Guangming; Zhang, Panyue; Zhang, Chang; Ren, Miaomiao; Zhang, Jiachao; Chen, Ming

2013-08-01

Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

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Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

2015-01-01

The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

Advances in bioleaching for recovery of metals and bioremediation of fuel ash and sewage sludge.

Science.gov (United States)

Gu, Tingyue; Rastegar, Seyed Omid; Mousavi, Seyyed Mohammad; Li, Ming; Zhou, Minghua

2018-08-01

Bioleaching has been successfully used in commercial metal mining for decades. It uses microbes to biosolubilize metal-containing inorganic compounds such as metal oxides and sulfides. There is a growing interest in using bioleaching for bioremediation of solid wastes by removing heavy metals from ash and sewage sludge. This review presents the state of the art in bioleaching research for recovery of metals and bioremediation of solid wastes. Various process parameters such as reaction time, pH, temperature, mass transfer rate, nutrient requirement, pulp density and particle size are discussed. Selections of more effective microbes are assessed. Pretreatment methods that enhance bioleaching are also discussed. Critical issues in bioreactor scale-up are analyzed. The potential impact of advances in biofilm and microbiome is explained. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bioleaching of incineration fly ash by Aspergillus niger - precipitation of metallic salt crystals and morphological alteration of the fungus.

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Xu, Tong-Jiang; Ramanathan, Thulasya; Ting, Yen-Peng

2014-09-01

This study examines the bioleaching of municipal solid waste incineration fly ash by Aspergillus niger , and its effect on the fungal morphology, the fate of the ash particles, and the precipitation of metallic salt crystals during bioleaching. The fungal morphology was significantly affected during one-step and two-step bioleaching; scanning electron microscopy revealed that bioleaching caused distortion of the fungal hyphae (with up to 10 μm hyphae diameter) and a swollen pellet structure. In the absence of the fly ash, the fungi showed a linear structure (with 2-4 μm hyphae diameter). Energy-dispersive X-ray spectroscopy and X-ray diffraction confirmed the precipitation of calcium oxalate hydrate crystals at the surface of hyphae in both one-step and two-step bioleaching. Calcium oxalate precipitation affects bioleaching via the weakening of the fly ash, thus facilitating the release of other tightly bound metals in the matrix.

Bioleaching of a low-grade nickel-copper sulfide by mixture of four thermophiles.

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Li, Shuzhen; Zhong, Hui; Hu, Yuehua; Zhao, Jiancun; He, Zhiguo; Gu, Guohua

2014-02-01

This study investigated thermophilic bioleaching of a low grade nickel-copper sulfide using mixture of four acidophilic thermophiles. Effects of 0.2g/L l-cysteine on the bioleaching process were further evaluated. It aimed at offering new alternatives for enhancing metal recoveries from nickel-copper sulfide. Results showed a recovery of 80.4% nickel and 68.2% copper in 16-day bioleaching without l-cysteine; while 83.7% nickel and 81.4% copper were recovered in the presence of l-cysteine. Moreover, nickel recovery was always higher than copper recovery. l-Cysteine was found contributing to lower pH value, faster microbial growth, higher Oxidation-Reduction Potential (ORP), higher zeta potential and absorbing on the sulfide surfaces through amino, carboxyl and sulfhydryl groups. X-ray Diffraction (XRD) patterns of leached residues showed generation of S, jarosite and ammoniojarosite. Denaturing Gradient Gel Electrophoresis (DGGE) results revealed that l-cysteine could have variant impacts on different microorganisms and changed the microbial community composition dramatically during nickel-copper sulfide bioleaching. Copyright © 2013 Elsevier Ltd. All rights reserved.

Copper Bioleaching in Chile

OpenAIRE

Juan Carlos Gentina; Fernando Acevedo

2016-01-01

Chile has a great tradition of producing and exporting copper. Over the last several decades, it has become the first producer on an international level. Its copper reserves are also the most important on the planet. However, after years of mineral exploitation, the ease of extracting copper oxides and ore copper content has diminished. To keep the production level high, the introduction of new technologies has become necessary. One that has been successful is bioleaching. Chile had the first...

[Effect of microbial nutrient concentration on improvement of municipal sewage sludge dewaterability through bioleaching].

Science.gov (United States)

Song, Yong-wei; Liu, Fen-wu; Zhou, Li-xiang

2012-08-01

In this study, shaking flask batch experiments and practical engineering application tests were performed to investigate the effect of microbial nutrient concentration on the dewaterability of municipal sewage sludge with 2%, 3%, 4% and 5% solid contents via bioleaching. Meanwhile, the changes of pH value and the utilization efficiency of microbial nutrients during bioleaching were analyzed in this study. The results showed that the pH value decreased gradually at the beginning and then maintained a stable state in the treatments with different solid contents, and the nutrients were completely used up by the microorganisms after 2 days of bioleaching. It was found that the SRF of 2%, 3%, 4%, 5% sludges decreased quickly and then rose gradually with the extension of bioleaching time. In addition, the higher solid content the greater the increase. It was determined that the optimum microbial nutrient dosage for sludge with solid content of 2%, 3%, 4% and 5% were 3.0 g x L(-1), 4.5 g x L(-1), 8.3 g x L(-1) and 12.8 g x L(-1) respectively. At this point, the lowest SRF of sludge with each solid content were 0.61 x 10(12) m x kg(-1), 1.22 x 10(12) m x kg(-1), 3.09 x 10(12) m x kg(-1) and 4.83 x 10(12) m x kg(-1), respectively. Through the engineering application, it was showed that diluting the solid content of sewage sludge from 5% to 3% before bioleaching was feasible. It could not only improve the dewaterability of bioleached sewage sludge (the SRF declined from 3.29 x 10(12) m x kg(-1) to 1.10 x 10(12) m x kg(-1)), but also shorten the sludge nutrient time (shortened from 4 days to 2.35 days) and reduce the operation costs. Therefore, the results of this study have important significance for the engineering application of bioleaching of municipal sewage sludge with high solid content.

Isolation and identification of indigenous lactic acid bacteria from North Sumatra river buffalo milk

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Heni Rizqiati

2015-06-01

Full Text Available Buffalo milk is a source of various lactic acid bacteria (LAB which is potential as culture starter as well as the probiotic. This study was conducted to isolate and identify LAB from indigenous North Sumatra river buffalo milk. Lactic acid bacteria was isolated and grown in medium De Man Rogosa Sharpe Agar (MRSA. The isolation was conducted to obtain pure isolate. The identification of LAB was studied in terms of morphology, physiology, biochemistry and survival on low pH. Morphology tests were conducted by Gram staining and cell forming; physiology tests were conducted for growing viability at pH 4.5 and temperature at 45oC; whereas biochemistry tests were conducted for CO2, dextran and NH3 productions. Determination of LAB species was conducted using Analytical Profile Index (API test CHL 50. Results of identification showed that 41 isolates were identified as LAB with Gram-positive, catalase-negative, rod and round shaped characteristics. Resistance test done to low pH (pH 2 for the lactic acid bacteria showed decrease of bacteria viability up to1.24±0.68 log cfu/ml. The resistant isolates at low pH were L12, L16, L17, L19, L20, M10, P8, S3, S19 and S20. Identification with API test CHL 50 for 10 isolates showed that four isolates were identified as Lactobacillus plantarum, L. brevis, L. pentosus and Lactococuslactis.

Influences of extracellular polymeric substances on the dewaterability of sewage sludge during bioleaching.

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Zhou, Jun; Zheng, Guanyu; Zhang, Xueying; Zhou, Lixiang

2014-01-01

Extracellular polymeric substances (EPS) play important roles in regulating the dewaterability of sludge. This study sought to elucidate the influence of EPS on the dewaterability of sludge during bioleaching process. Results showed that, in bioleaching system with the co-inoculation of Acidithiobacillus thiooxidans TS6 and Acidithiobacillus ferrooxidans LX5 (A. t+A. f system), the capillary suction time (CST) of sludge reduced from 255.9 s to 25.45 s within 48 h, which was obviously better than the controls. The correlation analysis between sludge CST and sludge EPS revealed that the sludge EPS significantly impacted the dewaterability of sludge. Sludge CST had correlation with protein content in slime and both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers, and the decrease of protein content in slime and decreases of both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers improved sludge dewaterability during sludge bioleaching process. Moreover, the low sludge pH (2.92) and the increasing distribution of Fe in the solid phase were another two factors responsible for the improvement of sludge dewaterability during bioleaching. This study suggested that during sludge bioleaching the growth of Acidithiobacillus species resulted in the decrease of sludge pH, the increasing distribution of Fe in the solid phase, and the decrease of EPS content (mainly including protein and/or polysaccharide) in the slime, TB-EPS, and Slime+LB+TB layers, all of which are helpful for sludge dewaterability enhancement.

Effect of sediment size on bioleaching of heavy metals from contaminated sediments of Izmir Inner Bay.

Science.gov (United States)

Guven, Duyusen E; Akinci, Gorkem

2013-09-01

The effect of sediment size on metals bioleaching from bay sediments was investigated by using fine (bioleaching. Microbial activity was provided with mixed cultures of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans. The bioleaching process was carried out in flask experiments for 48 days, by using 5% (W/V) of solid concentration in suspension. Bioleaching was found to be efficient for the removal of selected heavy metals from every size fraction of sediments, where the experiments with the smaller particles resulted in the highest solubilization ratios. At the end of the experimental period, Cr, Cu, Pb and Zn were solubilized to the ratios of 68%, 88%, 72%, and 91% from the fine sediment, respectively. Higher removal efficiencies can be explained by the larger surface area provided by the smaller particles. The changes in the chemical forms of metals were determined and most of the metal releases were observed from the reducible and organic fractions independent from grain size. Higher concentrations were monitored in the residual fraction after bioleaching period, suggesting they are trapped in this fraction, and cannot be solubilized under natural conditions.

Reagents and fractions impact on sulphide ore heap bioleaching at Smolnik mine

Science.gov (United States)

Oros, L. M.; Zavada, J.

2017-10-01

Mine Smolnik is one of the oldest sulphide ore mines in Europe and it is also an important part of bioleaching development. This paper follows previous attempts to extract residual metals from nearby heaps via variations in bioleaching reagents with regard to recent findings and needs in the related industry. Furthermore, economic and process relations between reagents and chosen heap fractions were also investigated in this case study.

Bioleaching of two different types of chalcopyrite by Acidithiobacillus ferrooxidans

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Dong, Ying-bo; Lin, Hai; Fu, Kai-bin; Xu, Xiao-fang; Zhou, Shan-shan

2013-02-01

Two different types of chalcopyrite (pyritic chalcopyrite and porphyry chalcopyrite) were bioleached with Acidithiobacillus ferrooxidans ATF6. The bioleaching of the pyritic chalcopyrite and porphyry chalcopyrite is quite different. The copper extraction reaches 46.96% for the pyritic chalcopyrite after 48-d leaching, but it is only 14.50% for the porphyry chalcopyrite. Proper amounts of initial ferrous ions can improve the efficiency of copper extraction for the two different types of chalcopyrite. The optimum dosage of ferrous ions for the pyritic chalcopyrite and porphyry chalcopyrite is different. The adsorption of ATF6 on the pyritic chalcopyrite and porphyry chalcopyrite was also studied in this paper. It is found that ATF6 is selectively adsorbed by the two different types of chalcopyrite; the higher adsorption onto the pyritic chalcopyrite than the porphyry chalcopyrite leads to the higher copper dissolution rate of the pyritic chalcopyrite. In addition, the zeta-potential of chalcopyrite before and after bioleaching further confirms that ATF6 is more easily adsorbed onto the pyritic chalcopyrite.

Characterization and uranium bioleaching performance of mixed iron- and sulfur-oxidizers versus iron-oxidizers

International Nuclear Information System (INIS)

Qian Li; Jing Sun; Dexin Ding; Qingliang Wang; Wenge Shi; Eming Hu; Xiaoyu Jiang; University of South China, Hengyang; Xingxing Wang

2017-01-01

In order to develop and apply mixed iron- and sulfur-oxidizers in uranium bioleaching, the characteristics of a mixed iron- and sulfur-oxidizing consortium (Consortium ISO) were comparatively investigated versus an iron-oxidizing consortium (Consortium IO). The results showed, the Consortium ISO exerted stronger oxidative ability and acid-producing ability than Consortium IO did. The synergy of sulfur-oxidizers and iron-oxidizers could change the structure and properties of the passivation substance, and work positively for eliminating the accumulation of passivation substance. In the bioleaching process, the uranium bioleaching experiments showed the recovery percentage of uranium reached 99.5% with Consortium ISO, 6.3% more than that of Consortium IO. (author)

Aplikasi Isolat Bakteri Indigenous Ubi Kayu Karet (Manihot glaziovii pada Fermentasi Pembuatan Mocaf

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K Kamsina

2017-12-01

Full Text Available Indigenous bacteria isolate of cassava rubber (Manihot glaziovii is an isolate of native bacteria which is available in rubber cassava tubers. Rubber cassava tuber is a cassava with a high content of cyanide acid (HCN. The study was aimed to see the ability of indigenous bacteria isolate of cassava cultivar rubber (BUG1 on mocaf making fermentation. This study used a completely randomized design with treatments (A addition of starter indigenous bacteria isolates of rubber variety (BUG1, (B without isolates, and (C without  fermentation. The resulting mocaf product was conducted a chemical tests consisted of moisture, ash, starch, acid degree, coarse fiber, and HCN content, while organoleptic tests consisted of color, aroma, and texture. The analysis results on the various treatments showed that the optimal treatment of mocaf flour produced was the addition of indigenous bacteria isolate starter of rubber variety (BUG1.ABSTRAKIsolat bakteri indigenous ubi kayu karet (Manihot glaziovii merupakan isolat bakteri asli yang berada dalam umbi ubi kayu karet. Ubi kayu kultivar  karet merupakan ubi kayu dengan kandungan asam sianida (HCN tinggi. Penelitian bertujuan untuk mempelajari kemampuan isolat bakteri indigenous ubi kayu kultivar karet (BUG1 pada fermentasi pembuatan mocaf. Penelitian ini menggunakan rancangan acak lengkap (RAL dengan perlakuan (A pemberian starter isolat bakteri indigenous varietas karet (BUG1, (B tanpa isolat, dan (C tanpa fermentasi. Terhadap produk mocaf  yang dihasilkan dilakukan uji kimia meliputi kadar air,  abu, pati, derajat asam, serat kasar, dan kadar HCN, sedangkan uji organoleptik meliputi warna, aroma, dan tekstur. Hasil analisis terhadap berbagai perlakuan menunjukkan perlakuan optimal untuk tepung mocaf  yang dihasilkan adalah pemberian starter isolat bakteri indigenous varietas karet (BUG1.

Bioleaching in batch tests for improving sludge dewaterability and metal removal using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans after cold acclimation.

Science.gov (United States)

Zhou, Qingyang; Gao, Jingqing; Li, Yonghong; Zhu, Songfeng; He, Lulu; Nie, Wei; Zhang, Ruiqin

2017-09-01

Bioleaching is a promising technology for removal of metals from sludge and improvement of its dewaterability. Most of the previous studies of bioleaching were focused on removal of metals; bioleaching in cold environments has not been studied extensively. In this study, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were acclimated at 15 °C and co-inoculated to explore the optimal conditions for improvement of sludge dewaterability and removal of metals by the sequencing batch reactors. The data show after 6 days of bioleaching at 15 °C, 89.6% of Zn, 72.8% of Cu and 39.4% of Pb were removed and the specific resistance to filtration (SRF) was reduced to ∼12%. In addition, the best conditions for bioleaching are an initial pH of 6, a 15% (v/v) inoculum concentration, and A. thiooxidans and A. ferrooxidans mixed in a ratio of 4:1. We found that bioleaching of heavy metals is closely related to final pH, while the sludge SRF is dominated by other factors. Bioleaching can be completed in 6 days, and the sludge dewaterability and removal of metals at 15 °C meet the requirements of most sewage treatment plants.

A copper-catalyzed bioleaching process for enhancement of cobalt dissolution from spent lithium-ion batteries

International Nuclear Information System (INIS)

Zeng, Guisheng; Deng, Xiaorong; Luo, Shenglian; Luo, Xubiao; Zou, Jianping

2012-01-01

Highlights: ► Catalytic ion was first applied to the bioleaching process of spent lithium-ion batteries. ► The bioleaching efficiency was great improved from 43.1% to 99.9% in the presence of copper ion. ► A new reaction model was proposed to explain the catalytic mechanism. - Abstract: A copper-catalyzed bioleaching process was developed to recycle cobalt from spent lithium-ion batteries (mainly LiCoO 2 ) in this paper. The influence of copper ions on bioleaching of LiCoO 2 by Acidithiobacillus ferrooxidans (A.f) was investigated. It was shown that almost all cobalt (99.9%) went into solution after being bioleached for 6 days in the presence of 0.75 g/L copper ions, while only 43.1% of cobalt dissolution was obtained after 10 days without copper ions. EDX, XRD and SEM analyses additionally confirmed that the cobalt dissolution from spent lithium-ion batteries could be improved in the presence of copper ions. The catalytic mechanism was investigated to explain the enhancement of cobalt dissolution by copper ions, in which LiCoO 2 underwent a cationic interchange reaction with copper ions to form CuCo 2 O 4 on the surface of the sample, which could be easily dissolved by Fe 3+ .

Bioleaching of incineration fly ash by Aspergillus niger – precipitation of metallic salt crystals and morphological alteration of the fungus

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Tong-Jiang Xu

2014-09-01

Full Text Available This study examines the bioleaching of municipal solid waste incineration fly ash by Aspergillus niger, and its effect on the fungal morphology, the fate of the ash particles, and the precipitation of metallic salt crystals during bioleaching. The fungal morphology was significantly affected during one-step and two-step bioleaching; scanning electron microscopy revealed that bioleaching caused distortion of the fungal hyphae (with up to 10 μm hyphae diameter and a swollen pellet structure. In the absence of the fly ash, the fungi showed a linear structure (with 2–4 μm hyphae diameter. Energy-dispersive X-ray spectroscopy and X-ray diffraction confirmed the precipitation of calcium oxalate hydrate crystals at the surface of hyphae in both one-step and two-step bioleaching. Calcium oxalate precipitation affects bioleaching via the weakening of the fly ash, thus facilitating the release of other tightly bound metals in the matrix.

Complete genome sequence of the bioleaching bacterium Leptospirillum sp. group II strain CF-1.

Science.gov (United States)

Ferrer, Alonso; Bunk, Boyke; Spröer, Cathrin; Biedendieck, Rebekka; Valdés, Natalia; Jahn, Martina; Jahn, Dieter; Orellana, Omar; Levicán, Gloria

2016-03-20

We describe the complete genome sequence of Leptospirillum sp. group II strain CF-1, an acidophilic bioleaching bacterium isolated from an acid mine drainage (AMD). This work provides data to gain insights about adaptive response of Leptospirillum spp. to the extreme conditions of bioleaching environments. Copyright © 2016 Elsevier B.V. All rights reserved.

Cr (VI) remediation by indigenous bacteria in soils contaminated by chromium-containing slag

International Nuclear Information System (INIS)

Chai Liyuan; Huang Shunhong; Yang Zhihui; Peng Bing; Huang Yan; Chen Yuehui

2009-01-01

Hexavalent chromium (Cr) is a toxic element causing serious environmental threat. Recently, more and more attention is paid to the bio-remediation of Cr (VI) in the contaminated soils. Cr (VI) remediation by indigenous bacteria in soils contaminated by chromium-containing slag at a steel-alloy factory in Hunan Province, China, was investigated in the present study. The results showed that when sufficient nutrients were amended into the contaminated soils, total Cr (VI) concentration declined from the initial value of 462.8 to 10 mg kg -1 at 10 days and the removal rate was 97.8%. Water soluble Cr (VI) decreased from the initial concentration of 383.8 to 1.7 mg kg -1 . Exchangeable Cr (VI) and carbonates-bound Cr (VI) were removed by 92.6% and 82.4%, respectively. Meanwhile, four Cr (VI) resistant bacterial strains were isolated from the soil under the chromium-containing slag. Only one strain showed a high ability for Cr (VI) reduction in liquid culture. This strain was identified as Pannonibacter phragmitetus sp. by gene sequencing of 16S rRNA. X-ray photoelectron spectroscope (XPS) analysis indicated that Cr (VI) was reduced into trivalent chromium. The results suggest that indigenous bacterial strains have potential application for Cr (VI) remediation in the soils contaminated by chromium-containing slag.

[Effect of different sludge retention time (SRT) on municipal sewage sludge bioleaching continuous plug flow reaction system].

Science.gov (United States)

Liu, Fen-Wu; Zhou, Li-Xiang; Zhou, Jun; Jiang, Feng; Wang, Dian-Zhan

2012-01-01

A plug-flow bio-reactor of 700 L working volume for sludge bioleaching was used in this study. The reactor was divided into six sections along the direction of the sludge movement. Fourteen days of continuous operation of sludge bioleaching with different sludge retention time (SRT) under the condition of 1.2 m3 x h(-1) aeration amount and 4 g x L(-1) of microbial nutritional substance was conducted. During sludge bioleaching, the dynamic changes of pH, DO, dewaterability (specific resistance to filtration, SRF) of sewage sludge in different sections were investigated in the present study. The results showed that sludge pH were maintained at 5.00, 3.00, 2.90, 2.70, 2.60 and 2.40 from section 1 to section 6 and the SRF of sludge was drastically decreased from initial 0.64 x 10(13) m x kg(-1) to the final 0.33 x 10(13) m x kg(-1) when bioleaching system reached stable at hour 72 with SRT 2.5d. In addition, the sludge pH were maintained at 5.10, 4.10, 3.20, 2.90, 2.70 and 2.60, the DO value were 0.43, 1.47, 3.29, 4.76, 5.75 and 5.88 mg x L(-1) from section 1 to section 6, and the SRF of sludge was drastically decreased from initial 0.56 x 10(13) to the final 0.20 x 10(13) m x kg(-1) when bioleaching system reached stable at hour 120 with SRT 2 d. The pH value was increased to 3.00 at section 6 at hour 48 h with SRT 1.25 d. The bioleaching system imbalanced in this operation conditions because of the utilization efficiency of microbial nutritional substance by Acidibacillus spp. was decreased. The longer sludge retention time, the easier bioleaching system reached stable. 2 d could be used as the optimum sludge retention time in engineering application. The bioleached sludge was collected and dewatered by plate-and-frame filter press to the moisture content of dewatered sludge cake under 60%. This study would provide the necessary data to the engineering application on municipal sewage sludge bioleaching.

Bioleaching of spent Zn-Mn or Ni-Cd batteries by Aspergillus species.

Science.gov (United States)

Kim, Min-Ji; Seo, Ja-Yeon; Choi, Yong-Seok; Kim, Gyu-Hyeok

2016-05-01

This research explores the recovery of metals from spent Zn-Mn or Ni-Cd batteries by a bioleaching using six Aspergillus species. Two different nutrients, malt extract and sucrose, were used to produce different types of organic acids. Oxalic acid and citric acid were shown to be the dominant organic acid in malt extract and sucrose media, respectively. In the bioleaching, the metal removal was higher in sucrose media than malt extract. All species, except A. niger KUC5254, showed more than 90% removal of metals from Zn-Mn battery. For Ni-Cd battery, more than 95% of metals was extracted by A. niger KUC5254 and A. tubingensis KUC5037. As a result, A. tubingensis KUC5037 which is a non-ochratoxigenic fungus was considered to have the greatest potential for improving the safety and efficiency of the bioleaching. Copyright © 2015 Elsevier Ltd. All rights reserved.

Indigenous endophytic seed bacteria promote seedling development and defend against fungal disease in browntop millet (Urochloa ramosa L.).

Science.gov (United States)

Verma, S K; White, J F

2018-03-01

This study was conducted to investigate indigenous seed endophyte effects on browntop millet seedling development. We report that seed-inhabiting bacterial endophytes are responsible for promoting seedling development, including stimulation of root hair formation, increasing root and shoot length growth and increasing photosynthetic pigment content of seedlings. Bacterial endophytes also improved resistance of seedlings to disease. A total of four endophytic bacteria were isolated from surface-sterilized seeds and identified by 16S rDNA sequencing as Curtobacterium sp. (M1), Microbacterium sp. (M2), Methylobacterium sp. (M3) and Bacillus amyloliquefaciens (M4). Removal of bacteria with streptomycin treatment from the seeds compromised seedling growth and development. When endophytes were reinoculated onto seeds, seedlings recovered normal development. Strains M3 and M4 were found to be most potent in promoting growth of seedlings. Bacteria were found to produce auxin, solubilize phosphate and inhibit fungal pathogens. Significant protection of seedlings from Fusarium infection was found using strain M4 in microcosm assays. The antifungal lipopeptide genes for surfactin and iturin were detected in M4; culture extracts of M4 showed a positive drop collapse result for surfactins. This study demonstrates that browntop millet seeds vector indigenous endophytes that are responsible for modulation of seedling development and protection of seedlings from fungal disease. This study is significant and original in that it is the first report of seed-inhabiting endophytes of browntop millet that influence seedling development and function in defence against soilborne pathogens. This study suggests that conservation and management of seed-vectored endophytes may be important in development of more sustainable agricultural practices. © 2017 The Society for Applied Microbiology.

Effect of particle-particle shearing on the bioleaching of sulfide minerals.

Science.gov (United States)

Chong, N; Karamanev, D G; Margaritis, A

2002-11-05

The biological leaching of sulfide minerals, used for the production of gold, copper, zinc, cobalt, and other metals, is very often carried out in slurry bioreactors, where the shearing between sulfide particles is intensive. In order to be able to improve the efficiency of the bioleaching, it is of significant importance to know the effect of particle shearing on the rate of leaching. The recently proposed concept of ore immobilization allowed us to study the effect of particle shearing on the rate of sulfide (pyrite) leaching by Thiobacillus ferrooxidans. Using this concept, we designed two very similar bioreactors, the main difference between which was the presence and absence of particle-particle shearing. It was shown that when the oxygen mass transfer was not the rate-limiting step, the rate of bioleaching in the frictionless bioreactor was 2.5 times higher than that in a bioreactor with particle friction (shearing). The concentration of free suspended cells in the frictionless bioreactor was by orders of magnitude lower than that in the frictional bioreactor, which showed that particle friction strongly reduces the microbial attachment to sulfide surface, which, in turn, reduces the rate of bioleaching. Surprisingly, it was found that formation of a layer of insoluble iron salts on the surface of sulfide particles is much slower under shearless conditions than in the presence of particle-particle shearing. This was explained by the effect of particle friction on liquid-solid mass transfer rate. The results of this study show that reduction of the particle friction during bioleaching of sulfide minerals can bring important advantages not only by increasing significantly the bioleaching rate, but also by increasing the rate of gas-liquid oxygen mass transfer, reducing the formation of iron precipitates and reducing the energy consumption. One of the efficient methods for reduction of particle friction is ore immobilization in a porous matrix. Copyright 2002

Vanadium Bioleaching Behavior by Acidithiobacillus ferrooxidans from a Vanadium-Bearing Shale

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Dunpei Wei

2018-01-01

Full Text Available This study investigated bioleaching behavior of vanadium from a vanadium-bearing shale using Acidithiobacillus ferrooxidans (A. ferrooxidans. Results showed a maximum recovery of 62% vanadium in 1.2-day bioleaching, which was 22.45% higher than the controls. Then, the vanadium leaching efficiency decreased significantly, only 24% of that was obtained on the tenth day. The vanadium extraction in 1.2 days was mainly attributed to the dissolution of vanadium in free oxides of shale. Fe3+ produced by A. ferrooxidans promoted the dissolution process. X-ray diffraction (XRD patterns of the leached residues confirmed the generation of jarosite. SEM-EDS analysis of the residues indicated that jarosite adsorbed on the shale and inhibited the further dissolution of vanadium. The relevance of V, Fe, S, O was quite good in the energy disperse X-ray spectrometry (EDS element mapping of jarosite, and acid-washing of the jarosite resulted in 31.6% of the vanadium in the precipitates desorption, indicating that the decrease of vanadium leaching efficiency in bioleaching process was caused by both adsorption and co-precipitation with jarosite.

A copper-catalyzed bioleaching process for enhancement of cobalt dissolution from spent lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zeng, Guisheng, E-mail: zengguisheng@hotmail.com [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Deng, Xiaorong [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian, E-mail: sllou@hnu.edu.cn [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Xubiao; Zou, Jianping [Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063 (China); School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

2012-01-15

Highlights: Black-Right-Pointing-Pointer Catalytic ion was first applied to the bioleaching process of spent lithium-ion batteries. Black-Right-Pointing-Pointer The bioleaching efficiency was great improved from 43.1% to 99.9% in the presence of copper ion. Black-Right-Pointing-Pointer A new reaction model was proposed to explain the catalytic mechanism. - Abstract: A copper-catalyzed bioleaching process was developed to recycle cobalt from spent lithium-ion batteries (mainly LiCoO{sub 2}) in this paper. The influence of copper ions on bioleaching of LiCoO{sub 2} by Acidithiobacillus ferrooxidans (A.f) was investigated. It was shown that almost all cobalt (99.9%) went into solution after being bioleached for 6 days in the presence of 0.75 g/L copper ions, while only 43.1% of cobalt dissolution was obtained after 10 days without copper ions. EDX, XRD and SEM analyses additionally confirmed that the cobalt dissolution from spent lithium-ion batteries could be improved in the presence of copper ions. The catalytic mechanism was investigated to explain the enhancement of cobalt dissolution by copper ions, in which LiCoO{sub 2} underwent a cationic interchange reaction with copper ions to form CuCo{sub 2}O{sub 4} on the surface of the sample, which could be easily dissolved by Fe{sup 3+}.

Impact of Molecular Hydrogen on Chalcopyrite Bioleaching by the Extremely Thermoacidophilic Archaeon Metallosphaera sedula▿

Science.gov (United States)

Auernik, Kathryne S.; Kelly, Robert M.

2010-01-01

Hydrogen served as a competitive inorganic energy source, impacting the CuFeS2 bioleaching efficiency of the extremely thermoacidophilic archaeon Metallosphaera sedula. Open reading frames encoding key terminal oxidase and electron transport chain components were triggered by CuFeS2. Evidence of heterotrophic metabolism was noted after extended periods of bioleaching, presumably related to cell lysis. PMID:20190092

Diversity, metabolic properties and arsenic mobilization potential of indigenous bacteria in arsenic contaminated groundwater of West Bengal, India.

Science.gov (United States)

Paul, Dhiraj; Kazy, Sufia K; Gupta, Ashok K; Pal, Taraknath; Sar, Pinaki

2015-01-01

Arsenic (As) mobilization in alluvial aquifers is caused by a complex interplay of hydro-geo-microbiological activities. Nevertheless, diversity and biogeochemical significance of indigenous bacteria in Bengal Delta Plain are not well documented. We have deciphered bacterial community compositions and metabolic properties in As contaminated groundwater of West Bengal to define their role in As mobilization. Groundwater samples showed characteristic high As, low organic carbon and reducing property. Culture-independent and -dependent analyses revealed presence of diverse, yet near consistent community composition mostly represented by genera Pseudomonas, Flavobacterium, Brevundimonas, Polaromonas, Rhodococcus, Methyloversatilis and Methylotenera. Along with As-resistance and -reductase activities, abilities to metabolize a wide range carbon substrates including long chain and polyaromatic hydrocarbons and HCO3, As3+ as electron donor and As5+/Fe3+ as terminal electron acceptor during anaerobic growth were frequently observed within the cultivable bacteria. Genes encoding cytosolic As5+ reductase (arsC) and As3+ efflux/transporter [arsB and acr3(2)] were found to be more abundant than the dissimilatory As5+ reductase gene arrA. The observed metabolic characteristics showed a good agreement with the same derived from phylogenetic lineages of constituent populations. Selected bacterial strains incubated anaerobically over 300 days using natural orange sand of Pleistocene aquifer showed release of soluble As mostly as As3+ along with several other elements (Al, Fe, Mn, K, etc.). Together with the production of oxalic acid within the biotic microcosms, change in sediment composition and mineralogy indicated dissolution of orange sand coupled with As/Fe reduction. Presence of arsC gene, As5+ reductase activity and oxalic acid production by the bacteria were found to be closely related to their ability to mobilize sediment bound As. Overall observations suggest that

Two-step bioleaching of copper and gold from discarded printed circuit boards (PCB).

Science.gov (United States)

Işıldar, Arda; van de Vossenberg, Jack; Rene, Eldon R; van Hullebusch, Eric D; Lens, Piet N L

2016-11-01

An effective strategy for environmentally sound biological recovery of copper and gold from discarded printed circuit boards (PCB) in a two-step bioleaching process was experimented. In the first step, chemolithotrophic acidophilic Acidithiobacillus ferrivorans and Acidithiobacillus thiooxidans were used. In the second step, cyanide-producing heterotrophic Pseudomonas fluorescens and Pseudomonas putida were used. Results showed that at a 1% pulp density (10g/L PCB concentration), 98.4% of the copper was bioleached by a mixture of A. ferrivorans and A. thiooxidans at pH 1.0-1.6 and ambient temperature (23±2°C) in 7days. A pure culture of P. putida (strain WCS361) produced 21.5 (±1.5)mg/L cyanide with 10g/L glycine as the substrate. This gold complexing agent was used in the subsequent bioleaching step using the Cu-leached (by A. ferrivorans and A. thiooxidans) PCB material, 44.0% of the gold was mobilized in alkaline conditions at pH 7.3-8.6, and 30°C in 2days. This study provided a proof-of-concept of a two-step approach in metal bioleaching from PCB, by bacterially produced lixiviants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of mineral constituents in the bioleaching of uranium from uraniferous sedimentary rock samples, Southwestern Sinai, Egypt

International Nuclear Information System (INIS)

Amin, Maisa M.; Elaassy, Ibrahim E.; El-Feky, Mohamed G.; Sallam, Abdel Sattar M.; Talaat, Mona S.; Kawady, Nilly A.

2014-01-01

Bioleaching, like Biotechnology uses microorganisms to extract metals from their ore materials, whereas microbial activity has an appreciable effect on the dissolution of toxic metals and radionuclides. Bioleaching of uranium was carried out with isolated fungi from uraniferous sedimentary rocks from Southwestern Sinai, Egypt. Eight fungal species were isolated from different grades of uraniferous samples. The bio-dissolution experiments showed that Aspergillus niger and Aspergillus terreus exhibited the highest leaching efficiencies of uranium from the studied samples. Through monitoring the bio-dissolution process, the uranium grade and mineralogic constituents of the ore material proved to play an important role in the bioleaching process. The tested samples asserted that the optimum conditions of uranium leaching are: 7 days incubation time, 3% pulp density, 30 °C incubation temperature and pH 3. Both fungi produced the organic acids, namely; oxalic, acetic, citric, formic, malonic, galic and ascorbic in the culture filtrate, indicating an important role in the bioleaching processes. - Highlights: • Aspergillus niger and Aspergillus terreus are the only isolates achieved highest leaching efficiency of uranium from the studied samples. • Bioleaching process directly related to variations in mineral constituents and uranium grades. • The optimum conditions of uranium bioleaching from its ores, were found to be 7 days, 3% pulp density, pH 3 and 30 °C. • A. niger and A. terreus organic acids play an important and effective role for uranium leaching process

Bioremediation of toxic substances by mercury resistant marine bacteria

Digital Repository Service at National Institute of Oceanography (India)

De, J.; Sarkar, A.; Ramaiah, N.

: ramaiah@nio.org Introduction: The principal goal of bioremediation is to enhance the natural biological-chemical transformations that render pollutants harmless as minerals and thus to provide a relief and, if feasible, a permanent solution...). The combination of soil bioleaching and bioprecipitation of the leached metals, by sulfate reducing bacteria, proved to be effective in removing and concentrating a range of metals, including Zn, Cu and Cd from metal-contaminated soils (White et al., 1998...

Enhancing sewage sludge dewaterability by bioleaching approach with comparison to other physical and chemical conditioning methods.

Science.gov (United States)

Liu, Fenwu; Zhou, Jun; Wang, Dianzhan; Zhou, Lixiang

2012-01-01

The sewage sludge conditioning process is critical to improve the sludge dewaterability prior to mechanical dewatering. Traditionally, sludge is conditioned by physical or chemical approaches, mostly with the addition of inorganic or organic chemicals. Here we report that bioleaching, an efficient and economical microbial method for the removal of sludge-borne heavy metals, also plays a significant role in enhancing sludge dewaterability. The effects of bioleaching and physical or chemical approaches on sludge dewaterability were compared. The conditioning result of bioleaching by Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans on sludge dewatering was investigated and compared with the effects of hydrothermal (121 degrees C for 2 hr), microwave (1050 W for 50 sec), ultrasonic (250 W for 2 min), and chemical conditioning (24% ferric chloride and 68% calcium oxide; dry basis). The results show that the specific resistance to filtration (SRF) or capillary suction time (CST) of sludge is decreased by 93.1% or 74.1%, respectively, after fresh sludge is conditioned by bioleaching, which is similar to chemical conditioning treatment with ferric chloride and calcium oxide but much more effective than other conditioning approaches including hydrothermal, microwave, and ultrasonic conditioning. Furthermore, after sludge dewatering, bioleached sludge filtrate contains the lowest concentrations of chroma (18 times), COD (542 mg/L), total N (TN, 300 mg/L), NH4(+)-N (208 mg/L), and total P (TP, 2 mg/L) while the hydrothermal process resulted in the highest concentration of chroma (660 times), COD (18,155 mg/L), TN (472 mg/L), NH4(+)-N (381 mg/L), and TP (191 mg/L) among these selected conditioning methods. Moreover, unlike chemical conditioning, sludge bioleaching does not result in a significant reduction of organic matter, TN, and TP in the resulting dewatered sludge cake. Therefore, considering sludge dewaterability and the chemical properties of sludge

Effects of stimulation of copper bioleaching on microbial community in vineyard soil and copper mining waste.

Science.gov (United States)

Andreazza, Robson; Okeke, Benedict C; Pieniz, Simone; Bortolon, Leandro; Lambais, Márcio R; Camargo, Flávio A O

2012-04-01

Long-term copper application in vineyards and copper mining activities cause heavy metal pollution sites. Such sites need remediation to protect soil and water quality. Bioremediation of contaminated areas through bioleaching can help to remove copper ions from the contaminated soils. Thus, the aim of this work was to evaluate the effects of different treatments for copper bioleaching in two diverse copper-contaminated soils (a 40-year-old vineyard and a copper mining waste) and to evaluate the effect on microbial community by applying denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA amplicons and DNA sequence analysis. Several treatments with HCl, H(2)SO(4), and FeSO(4) were evaluated by stimulation of bioleaching of copper in the soils. Treatments and extractions using FeSO(4) and H(2)SO(4) mixture at 30°C displayed more copper leaching than extractions with deionized water at room temperature. Treatment with H(2)SO(4) supported bioleaching of as much as 120 mg kg(-1) of copper from vineyard soil after 115 days of incubation. DGGE analysis of the treatments revealed that some treatments caused greater diversity of microorganisms in the vineyard soil compared to the copper mining waste. Nucleotide Blast of PCR-amplified fragments of 16S rRNA gene bands from DGGE indicated the presence of Rhodobacter sp., Silicibacter sp., Bacillus sp., Paracoccus sp., Pediococcus sp., a Myxococcales, Clostridium sp., Thiomonas sp., a firmicute, Caulobacter vibrioides, Serratia sp., and an actinomycetales in vineyard soil. Contrarily, Sphingomonas was the predominant genus in copper mining waste in most treatments. Paracoccus sp. and Enterobacter sp. were also identified from DGGE bands of the copper mining waste. Paracoccus species is involved in the copper bioleaching by sulfur oxidation system, liberating the copper bounded in the soils and hence promoting copper bioremediation. Results indicate that stimulation of bioleaching with a combination of FeSO(4

Remediation of heavy-metal contaminated sediments by means of bioleaching. Study: project results - economic efficiency - market assessment. Final report; Reinigung schwermetallbelasteter Sedimente durch Bioleaching. Studie: Projektergebnisse - Wirtschaftlichkeit - Marktbewertung. Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Loeser, C; Zehnsdorf, A; Hoffmann, P; Seidel, H; Schmerold, R

2002-07-01

Sediments in running and stationary waters continue to pose environmental as well as cost problems. In Saxonian waters alone some 3.7 million m{sup 3} of sediments mostly contaminated with heavy metals from mining or industrial activities are in need of remediation. For lack of practicable remediation methods excavated sediments nowadays are landfilled. However, due to its persisting hazard potential this solution is ecologically unsatisfactory. Exposure of these sediments to oxygen leads to microbial oxidation and acidification processes and hence partial solubilisation of heavy metals. If allowed to proceed uncontrolled this natural bioleaching process poses an environmental hazard. However, if accelerated artificially through activation of autochtonous sulphur oxidising bacteria (e.g. thiobacilli) it can be used to remediate sediments. The goal is to provide a semi-natural sediment decontamination process based on natural biological solubilisation potentials After decontamination, sediments can be returned to the materials cycle as soil substrates. The present process was developed using heavily contaminated sediments from the Weisse Elster region south of Leipzig as example material. For economic reasons it was decided to use a fixed-bed leaching process based on percolation. It proved necessary to use a multistage process. The laboratory and technical-scale experiments were dedicated to developing and implementing measures for faster metal solubilisation. [German] Gewaessersedimente sind ein bisher ungeloestes Umwelt- und Kostenproblem. Allein aus den Gewaessern Sachsens muessen ca. 3,7 Millionen m{sup 3} Sedimente beraeumt werden, diese sind zum grossen Teil mit Schwermetallen aus bergbaulichen und industriellen Aktivitaeten belastet. Gegenwaertig werden die ausgebaggerten Sedimente deponiert, da praktikable Sanierungsverfahren fehlen. Die Deoponierung ist wegen des weiter bestehenden Gefaehrdungspotentials keine oekologisch befriedigende Loesung. Kommen die

BIOREMEDIATION OF CONTAMINATED WASTE BY CADMIUM (Cd IN WATERS USING INDIGEN BACTERIUM WITH EX-SITU WAY

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Titik Wijayanti

2017-10-01

Full Text Available The bioremediation technique for a contaminated liquid waste of heavy metals using indigenous bacteria is a convenient alternative to steps continues to be developed. The research aims to find out the effectiveness of an indigenous bacterial consortium in bioremediation of contaminated liquid waste by cadmium by ex-situ. Experiments were arranged in RAL made in ex-situ where a liquid waste industry was given five treatments, namely control and four indigenous bacterial consortia (A, D, E, and J obtained from the isolation of bacteria originating from cadmium-contaminated of waste in Pasuruan district. Furthermore conducted observations of BOD5, COD, d.o. and Cd for seven days to find out the effectiveness of bioremediation. The results showed the four indigenous bacteria consortia have the bioremediation ability to reduce levels of cadmium, BOD5, COD, and increasing levels of DO. Indigenous bacterial consortia D has the best ability of liquid industrial waste bioremediation by ex-situ. Indigenous bacterial consortia J has the best of capacity reduction levels of cadmium, then the other of indigenous bacterial consortia.

Linking leach chemistry and microbiology of low-grade copper ore bioleaching at different temperatures

Science.gov (United States)

Jia, Yan; Sun, He-yun; Tan, Qiao-yi; Gao, Hong-shan; Feng, Xing-liang; Ruan, Ren-man

2018-03-01

The effects of temperature on chalcocite/pyrite oxidation and the microbial population in the bioleaching columns of a low-grade chalcocite ore were investigated in this study. Raffinate from the industrial bioleaching heap was used as an irrigation solution for columns operated at 20, 30, 45, and 60°C. The dissolution of copper and iron were investigated during the bioleaching processes, and the microbial community was revealed by using a high-throughput sequencing method. The genera of Ferroplasma, Acidithiobacillus, Leptospirillum, Acidiplasma, and Sulfobacillus dominated the microbial community, and the column at a higher temperature favored the growth of moderate thermophiles. Even though microbial abundance and activity were highest at 30°C, the column at a higher temperature achieved a much higher Cu leaching efficiency and recovery, which suggested that the promotion of chemical oxidation by elevated temperature dominated the dissolution of Cu. The highest pyrite oxidation percentage was detected at 45°C. Higher temperature resulted in precipitation of jarosite in columns, especially at 60°C. The results gave implications to the optimization of heap bioleaching of secondary copper sulfide in both enhanced chalcocite leaching and acid/iron balance, from the perspective of leaching temperature and affected microbial community and activity.

Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

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Mrazikova Anna

2015-06-01

Full Text Available Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al from printed circuit boards (PCBs. In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be 100, 92, 89 and 20% of Cu, Ni, Zn and Al, respectively. The mixed culture revealed higher bacterial stability. The main factor responsible for high metal recovery was the ability of the mixed culture to maintain the low pH during the whole process. The pure culture of A. thiooxidans had no significant effect on metal bioleaching from PCBs.

Bioleaching of nickel by Aspergillus humicola SKP102 isolated from Indian lateritic overburden

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Suchhanda Ghosh

2016-01-01

Full Text Available The lateritic deposits spread over the Eastern Ghats of Sukinda Valley, Odisha, India, produce a huge amount of overburden annually as a byproduct of chromite mining. This chromite mining overburden contains nickel, the only source of the metal in the country. During this study Aspergillus humicola SKP102, an indigenous fungus isolated from the mining overburden was employed for the leaching of nickel. About 53.89% of the nickel could be leached by the fungus when grown in batch mode using a Czapek dox medium containing 2% (w/v of the mining overburden. The parameters affecting bioleaching were optimized in order to grow the fungus and leach the metal. Of the different options of cheap carbon sources, straw infusion and molasses emerged as viable options for the growth of the fungus and the leaching of nickel. Two-step and indirect techniques were also used for this purpose, and they resulted in 53.09% and 65.04% Ni leaching respectively. Adding diluted sulfuric acid to the leaching medium resulted in 97.05% nickel recovery from the overburden pulp. A. humicola SKP102 could be a potential tool for leaching nickel from the mining overburden.

Effect of mineral constituents in the bioleaching of uranium from uraniferous sedimentary rock samples, Southwestern Sinai, Egypt.

Science.gov (United States)

Amin, Maisa M; Elaassy, Ibrahim E; El-Feky, Mohamed G; Sallam, Abdel Sattar M; Talaat, Mona S; Kawady, Nilly A

2014-08-01

Bioleaching, like Biotechnology uses microorganisms to extract metals from their ore materials, whereas microbial activity has an appreciable effect on the dissolution of toxic metals and radionuclides. Bioleaching of uranium was carried out with isolated fungi from uraniferous sedimentary rocks from Southwestern Sinai, Egypt. Eight fungal species were isolated from different grades of uraniferous samples. The bio-dissolution experiments showed that Aspergillus niger and Aspergillus terreus exhibited the highest leaching efficiencies of uranium from the studied samples. Through monitoring the bio-dissolution process, the uranium grade and mineralogic constituents of the ore material proved to play an important role in the bioleaching process. The tested samples asserted that the optimum conditions of uranium leaching are: 7 days incubation time, 3% pulp density, 30 °C incubation temperature and pH 3. Both fungi produced the organic acids, namely; oxalic, acetic, citric, formic, malonic, galic and ascorbic in the culture filtrate, indicating an important role in the bioleaching processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bioleaching of copper, aluminum, magnesium and manganese from ...

African Journals Online (AJOL)

The present study was done to check the bioleaching feasibility of brown shale for the recovery of copper (Cu), aluminum (Al), magnesium (Mg) and manganese (Mn) ions using Ganoderma lucidum. Different experimental parameters were optimized for the enhanced recovery of metals ions. Effect of different substrates like ...

Effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

Science.gov (United States)

Yu, Run-lan; Liu, Jing; Tan, Jian-xi; Zeng, Wei-min; Shi, Li-juan; Gu, Guo-hua; Qin, Wen-qing; Qiu, Guan-zhou

2014-04-01

The pH value plays an important role in the bioleaching of sulphide minerals. The effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans was investigated in different phases of bacterial growth during chalcopyrite bioleaching. It is found that extracellular polysaccharide secretion from the cells attached to chalcopyrite is more efficiently than that of the free cells in the bioleaching solution. Three factors, pH values, the concentration of soluble metal ions, and the bacterial growth and metabolism, affect extracellular polysaccharide secretion in the free cells, and are related to the bacterial growth phase. Extracellular polysaccharide secretion from the attached cells is mainly dependent on the pH value of the bacterial culture.

Growth of indigenous lactic acid bacteria Lactobacillus plantarum-pentosus T14 and Lactobacillus plantarum-pentosus T35 in kerandang (Canavalia virosa milk and changes of raffinose

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Rahayu, E. S.

2013-01-01

Full Text Available Aims: Kerandang (Canavalia virosa beans are good source of protein, yet predominantly kerandang foods are not widely accepted mainly because of their beany flavour the belief that they cause flatulence. The objectives of this research were to evaluate of viability of lactic acid bacteria from Indonesia indigenous fermented food in kerandang milk and its ability to metabolize indigestible oligossacharide raffinose.Methodology and results: Two strains of Indonesia indigenous lactic acid bacteria (LAB, namely Lactobacillus plantarum-pentosus T14 and Lactobacillus plantarum-pentosus T35 were used for fermentation of kerandang milk. The results showed that all strains of lactic acid bacteria possess the ability to grow and produce of lactic acid in kerandang milk, indicated that total acid (TA increase, pH decrease and their counts of LAB increase during fermentation period (0-24 h. The two strains of lactic acid bacteria were also able to metabolize raffinose into simple sugar (sucrose, glucose, fructose and galactose during fermentation at 37 °C, however the raffinose transformation by L. plantarum-pentosus T14 more ability than L. plantarum-pentosus T35. The metabolism of raffinose during fermentation by L. plantarum-pentosus T14 and L. plantarum-pentosus T35 were 98.23% and 48.98%, respectively.Conclusion, significance and impact of study: Kerandang milk fermented by lactic acid bacteria can decrease of saccharide raffinose cause of flatulence. Thus, lactic fermented of kerandang milk be safer for consumption.

Distribution of hydrocarbon-degrading bacteria in the soil environment and their contribution to bioremediation.

Science.gov (United States)

Fukuhara, Yuki; Horii, Sachie; Matsuno, Toshihide; Matsumiya, Yoshiki; Mukai, Masaki; Kubo, Motoki

2013-05-01

A real-time PCR quantification method for indigenous hydrocarbon-degrading bacteria (HDB) carrying the alkB gene in the soil environment was developed to investigate their distribution in soil. The detection limit of indigenous HDB by the method was 1 × 10(6) cells/g-soil. The indigenous HDB were widely distributed throughout the soil environment and ranged from 3.7 × 10(7) to 5.0 × 10(8) cells/g-soil, and the ratio to total bacteria was 0.1-4.3 %. The dynamics of total bacteria, indigenous HDB, and Rhodococcus erythropolis NDKK6 (carrying alkB R2) during bioremediation were analyzed. During bioremediation with an inorganic nutrient treatment, the numbers of these bacteria were slightly increased. The numbers of HDB (both indigenous bacteria and strain NDKK6) were gradually decreased from the middle stage of bioremediation. Meanwhile, the numbers of these bacteria were highly increased and were maintained during bioremediation with an organic nutrient. The organic treatment led to activation of not only the soil bacteria but also the HDB, so an efficient bioremediation was carried out.

Evaluation of Aliphatic and Aromatic Compounds Degradation by Indigenous Bacteria Isolated from Soil Contaminated with Petroleum

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Farhad Gilavand

2015-12-01

Full Text Available Background:  The major of this study was to isolate oil-degrading bacteria from soil contaminated with petroleum and examining the removal of hydrocarbons by these bacteria. Methods: Oil-degrading colonies were purified from the samples obtained of around Ahvaz oil wells. Organic matter degradation was investigated with 1 g of crude oil in basal salt medium (BSM as sole carbon source. The growth rate was determined through total protein assay and hydrocarbon consuming was measured through organic carbon oxidation and titration by dichromate as oxidizing agent. Results: Two potential isolates named S1 and S2 strains were screened and identified as Planococcus and Pseudomonas aeruginosa. As results for S1 and S2 could degrade 80.86 and 65.6% of olive oil, 59.6 and 35.33 of crude oil, while 32 and 26.15 % of coal tar were consumed during 14 days incubation. Conclusion: The results of this investigation showed these indigenous strains high capability to biodegradation at short time and are desirable alternatives for treatment of oil pollutants.

Insights into the Surface Transformation and Electrochemical Dissolution Process of Bornite in Bioleaching

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Hongbo Zhao

2018-04-01

Full Text Available In this work, density functional theory (DFT calculations, X-ray photoelectron spectroscopy (XPS and electrochemistry analysis were combined to analyze the electrochemical dissolution process of bornite during bioleaching. DFT calculations showed that bornite was a conductor with metallic conductivity. The formula of bornite may be (Cu+5Fe3+(S2−4 and the surface reconstruction of (111-S surface was discussed. Electrochemistry and XPS analysis showed that bornite tended to be directly oxidized with high conductivity when the potential was higher than 0.3 V vs. Ag/AgCl. Elemental sulfur (S0, FeOOH and CuS were the main intermediate species on the bornite surface during the oxidation process. The production of S0 and FeOOH on bornite surface can be significantly accelerated with increased redox potential, but no insoluble sulfate (SO42− formed on bornite surface in 0.3–0.65 V vs. Ag/AgCl. The oxidative dissolution of bornite was significantly accelerated with increasing redox potential, which was one important reason why mixed culture was more effective than single strains of A. caldus and L. ferriphilum in bornite bioleaching. The insoluble SO42− was formed mainly through the chemical reactions in solution and then covered the bornite surface in bioleaching. Based on the obtained results, a model for interpreting the dissolution process of bornite in bioleaching was proposed.

Bioleaching - an alternate uranium ore processing technology for India

International Nuclear Information System (INIS)

Abilash; Mehta, K.D.; Kumar, V.; Pandey, B.D.; Tamarakar, P.K.

2010-01-01

Meeting the feed supply of uranium fuel in the present and planned nuclear reactors calls for huge demand of uranium, which at the current rate of production, shows a mismatch. The processing methods at UCIL (DAE) needs to be modified/changed or re-looked into because of its very suitability in near future for low-index raw materials which are either unmined or stacked around if mined. There is practically no way to process tailings with still some values. Efforts were made to utilize such resources (low-index ore of Turamdih mines, containing 0.03% U 3 O 8 ) by NML in association with UCIL as a national endeavor. In this area, the R and D work showed the successful development of a bioleaching process from bench scale to lab scale columns and then finally to the India's first ever large scale column, from the view point of harnessing such a processing technology as an alternative for the uranium industry and nuclear sector in the country. The efforts culminated into the successful operation of large scale trials at the 2 ton level column uranium bioleaching that was carried out at the site of UCIL, Jaduguda yielding a maximum recovery of 69% in 60 days. This achievement is expected to pave the way for scaling up the activity to a 100T or even more heap bioleaching trials for realization of this technology, which needs to be carried out with the support of the nuclear sector in the country keeping in mind the national interest. (author)

Abundance and activity of oil-degrading and indigenous bacteria in sediment microcosms

International Nuclear Information System (INIS)

Araujo, R.; Molina, M.; Bachoon, D.

1995-01-01

The responses of bacterial community composition and degradation crude oil to applications of bioremediation products and plant detrital material were investigated in wetlands microcosms. The microcosms were constructed of sieved sediments and operated as tidal marshes. Products included nutrients, organisms, surfactants and combinations thereof; dried ground Spartina was the source of detrital material. Plate count and most probable-number techniques were used to enumerate microbial populations and GC/MS analysis of indicator petroleum hydrocarbons was used to assess oil degradation. Microbial communities were characterized by whole-genome hybridization and specific probes for bacterial groups, including Pseudomonas, Streptomycetes, Vibrio, and sulfate-reducing bacteria. Although the total microbial numbers were similar in all bioremediation treatments, the numbers of oil degraders increased two to three log units in the fertilizer and microbial-degrader-enriched treatments. Oil-degraders comprised the largest fraction of the total population in the treatment amended with microbial degraders, apparently at the expense of indigenous bacteria, as indicated by specific probes. Oil-degraders were also detected in the subsurface in all treatments except the controls. The extent of oil degradation was not consistent with bacterial numbers; only nutrient additions resulted in significantly enhanced degradation of oil. After 1 month of microcosm operation, oil-degraders had increased at least two orders of magnitude in sediment surface layers when oil was added alone or with Spartina detritus, although total bacterial numbers and the number of oil-degraders decreased to near initial levels by 2 months. The peak coincides with bacterial utilization of the alkane fraction of petroleum hydrocarbons

Catalytic potential of selected metal ions for bioleaching, and potential techno-economic and environmental issues: A critical review.

Science.gov (United States)

Pathak, Ashish; Morrison, Liam; Healy, Mark Gerard

2017-04-01

Bioleaching is considered to be a low-cost, eco-friendly technique for leaching valuable metals from a variety of matrixes. However, the inherent slow dissolution kinetics and low metal leaching yields have restricted its wider commercial applicability. Recent advancements in bio-hydrometallurgy have suggested that these critical issues can be successfully alleviated through the addition of a catalyst. The catalyzing properties of a variety of metals ions (Ag + , Hg ++ , Bi +++ , Cu ++ , Co ++ etc.) during bioleaching have been successfully demonstrated. In this article, the role and mechanisms of these metal species in catalyzing bioleaching from different minerals (chalcopyrite, complex sulfides, etc.) and waste materials (spent batteries) are reviewed, techno-economic and environmental challenges associated with the use of metals ions as catalysts are identified, and future prospectives are discussed. Based on the analysis, it is suggested that metal ion-catalyzed bioleaching will play a key role in the development of future industrial bio-hydrometallurgical processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential of bioleaching of arsenic from ash soils from site Zemianske Kostolany

International Nuclear Information System (INIS)

Slebodnikova, Z.; Petkova, K.; Molnarova, M.

2014-01-01

The essence of this work is to study bioleaching of potentially toxic elements, arsenic, using the filamentous fungus Asperillus niger. As a model locality was chosen Zemianske Kosto.any, which represents the heart of coal mining in Slovakia. Species A. niger was isolated from anthropogenic sediments with a high content of potentially toxic elements, especially arsenic. Filamentous fungus A. niger was put on soil samples from the site model. The aim of this work is to evaluate the potential of arsenic bioleaching using the three different soil samples for analysis (1 g, 10 g and 100 g). It was found that the most efficient leaching of arsenic was achieved with furnish at 1 g of the substrate. The highest portion of arsenic was released into the medium, values range from 131.75 μg.dm -3 to 1517.55 μg.dm -3 . At the furnish 10 g of soil were released lower amounts, from 69.77 μg.dm -3 to 553.45 μg.dm -3 . Lowest bioleaching efficiency was achieved with the furnish 100 g, values are from 38.02 μg.dm -3 to 254.07 μg.dm -3 . (authors)

Bioleaching of copper, cobalt and zinc from black shale by ...

African Journals Online (AJOL)

STORAGESEVER

2009-10-05

Oct 5, 2009 ... duce organic acid metabolites which include citric, oxalic and gluconic acids during ... acid metabolites like citric, oxalic, malic gluconic acids used for bioleaching of ..... polluted soils using oxalate. J. Water, Air, Soil Pollut.

Bioleaching of two different genetic types of chalcopyrite and their comparative mineralogical assessment.

Science.gov (United States)

Deng, Sha; Gu, Guohua; Ji, Jing; Xu, Baoke

2018-02-01

The bioleaching of two different genetic types of chalcopyrite by the moderate thermophile Sulfobacillus thermosulfidooxidans was investigated by leaching behaviors elucidation and their comparative mineralogical assessment. The leaching experiment showed that the skarn-type chalcopyrite (STC) revealed a much faster leaching rate with 33.34% copper extracted finally, while only 23.53% copper was bioleached for the porphyry-type chalcopyrite (PTC). The mineralogical properties were analyzed by XRD, SEM, XPS, and Fermi energy calculation. XRD indicated that the unit cell volume of STC was a little larger than that of PTC. SEM indicated that the surface of STC had more steps and ridges. XPS spectra showed that Cu(I) was the dominant species of copper on the surfaces of the two chalcopyrite samples, and STC had much more copper with lower Cu 2p 3/2 binding energy. Additionally, the Fermi energy of STC was much higher than that of PTC. These mineralogical differences were in good agreement with the bioleaching behaviors of chalcopyrite. This study will provide some new information for evaluating the oxidation kinetics of chalcopyrite.

Process controls for improving bioleaching performance of both Li and Co from spent lithium ion batteries at high pulp density and its thermodynamics and kinetics exploration.

Science.gov (United States)

Niu, Zhirui; Zou, Yikan; Xin, Baoping; Chen, Shi; Liu, Changhao; Li, Yuping

2014-08-01

Release of Co and Li from spent lithium ion batteries (LIBs) by bioleaching has attracted growing attentions. However, the pulp density was only 1% or lower, meaning that a huge quantity of media was required for bioleaching. In this work, bioleaching behavior of the spent LIBs at pulp densities ranging from 1% to 4% was investigated and process controls to improve bioleaching performance at pulp density of 2% were explored. The results showed that the pulp density exerted a considerable influence on leaching performance of Co and Li. The bioleaching efficiency decreased respectively from 52% to 10% for Co and from 80% to 37% for Li when pulp density rose from 1% to 4%. However, the maximum extraction efficiency of 89% for Li and 72% for Co was obtained at pulp density of 2% by process controls. Bioleaching of the spent LIBs has much greater potential to occur than traditional chemical leaching based on thermodynamics analysis. The product layer diffusion model described best bioleaching behavior of Co and Li. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bioleaching of UO22+ ions from a Romanian poor uranium ore

International Nuclear Information System (INIS)

Cecal, Al.; Popa, K.; Moraru, R.T.; Patachia, S.

2002-01-01

An experimental study on the bioleaching of a poor uranium ore by means of hydrophytic plants Lemna minor and Riccia fluitans, under various operating conditions is discussed. The maximum degree of bioleaching (42%) of the reduced uranium species to U(VI) has been attained for the ore-Lemna minor-alkaline carbonate solution system. The UO 2 2+ ions amount accumulated in the plants is negligible as compared to the dissolved quantity, owing to the ionic competition between uranyl ions and the cations necessary to the mineral nutrition. The X-ray diffraction patterns prove that the uranium species in pyrochlore mineral are completely oxidized to U(VI), while thucolite is only partially turned into UO 2 2+ ions, in the presence of living plants. (author)

Iron removal on feldspar by using Averrhoa bilimbii as bioleaching agent

Science.gov (United States)

Amin, Muhammad; Aji, Bramantyo B.; Supriyatna, Yayat Iman; Bahfie, Fathan

2017-01-01

Investigation of Averrhoa bilimbii as bioleaching agent was carried out. Parameters of leaching duration, acid concentration, and temperature were performed in iron removal process. Feldspar with sized 149 µm was diluted in 30 ml acid solution in order to reduce its iron content. The experimental results showed a good technical feasibility of the process which iron oxide content of feldspar was decreased from 2.24% to 0.29%. The lowest iron concentration remained was obtained after 5 hours of leaching treatment at 60 °C, and concentrated (100 vol%) Averrhoa bilimbii extract as bioleaching agent. SEM characterizations were carried out on the feldspar before and after the leaching treatment. The result shows that there were no significant effect of leaching process on the ore morphology.

The potential of amino acids in alkaliphilic bioleaching

International Nuclear Information System (INIS)

Barthen, Robert; Karimzadeh, Lotfallah; Gruendig, Marion; Franke, Karsten; Lippmann-Pipke, Johanna

2017-01-01

Bioleaching has become a major production process for copper contributing currently to around 15 % of the world wide copper production. However, non-sulfidic and/or complex ores are still not efficiently minable by conventional methods. In this study, we investigated the effect of copper complexing molecules such as amino acids on Cu"2"+ and S"2"- solubilization from covellite.

Bioleaching of serpentine group mineral by fungus Talaromyces flavus: application for mineral carbonation

Science.gov (United States)

Li, Z.; Lianwen, L.; Zhao, L.; Teng, H.

2011-12-01

Many studies of serpentine group mineral dissolution for mineral carbonation have been published in recent years. However, most of them focus mainly on either physical and chemical processes or on bacterial function, rather than fungal involvement in the bioleaching of serpentine group mineral. Due to the excessive costs of the magnesium dissolution process, finding a lower energy consumption method will be meaningful. A fungal strain Talaromyces flavus was isolated from serpentinic rock of Donghai (China). No study of its bioleaching ability is currently available. It is thus of great significance to explore the impact of T. flavus on the dissolution of serpentine group mineral. Serpentine rock-inhabiting fungi belonging to Acremonium, Alternaria, Aspergillus, Botryotinia, Cladosporium, Clavicipitaceae, Cosmospora, Fusarium, Monascus, Paecilomyces, Penicillium, Talaromyces, Trichoderma were isolated. These strains were chosen on the basis of resistance to magnesium and nickel characterized in terms of minimum inhibiting concentration (MIC). Specifically, the strain Talaromyces flavus has a high tolerance to both magnesium (1 mol/L) and nickel (10 mM/L), and we examine its bioleaching ability on serpentine group mineral. Contact and separation experiments (cut-off 8 000-14 000 Da), as well as three control experiments, were set up for 30 days. At least three repeated tests were performed for each individual experiment. The results of our experiments demonstrate that the bioleaching ability of T. flavus towards serpentine group mineral is evident. 39.39 wt% of magnesium was extracted from lizardite during the bioleaching period in the contact experiment, which showed a dissolution rate at about a constant 0.126 mM/d before reaching equilibrium in 13 days. The amount of solubilized Mg from chrysotile and antigorite were respectively 37.79 wt% and 29.78 wt% in the contact experiment. These results make clear the influence of mineral structure on mineral bioleaching

Horizontal gene transfer between bacteria.

Science.gov (United States)

Heuer, Holger; Smalla, Kornelia

2007-01-01

Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

Community dynamics of attached and free cells and the effects of attached cells on chalcopyrite bioleaching by Acidithiobacillus sp.

Science.gov (United States)

Yang, Hailin; Feng, Shoushuai; Xin, Yu; Wang, Wu

2014-02-01

The community dynamics of attached and free cells of Acidithiobacillus sp. were investigated and compared during chalcopyrite bioleaching process. In the mixed strains system, Acidithiobacillus ferrooxidans was the dominant species at the early stage while Acidithiobacillus thiooxidans owned competitive advantage from the middle stage to the end of bioprocess. Meanwhile, compared to A. ferrooxidans, more significant effects of attached cells on free biomass with A. thiooxidans were shown in either the pure or mixed strains systems. Moreover, the effects of attached cells on key chemical parameters were also studied in different adsorption-deficient systems. Consistently, the greatest reduction of key chemical ion was shown with A. thiooxidans and the loss of bioleaching efficiency was high to 50.5%. These results all demonstrated the bioleaching function of attached cells was more efficient than the free cells, especially with A. thiooxidans. These notable results would help us to further understand the chalcopyrite bioleaching. Copyright © 2013 Elsevier Ltd. All rights reserved.

Insights to the effects of free cells on community structure of attached cells and chalcopyrite bioleaching during different stages.

Science.gov (United States)

Feng, Shoushuai; Yang, Hailin; Wang, Wu

2016-01-01

The effects of free cells on community structure of attached cells and chalcopyrite bioleaching by Acidithiobacillus sp. during different stages were investigated. The attached cells of Acidithiobacillus thiooxidans owned the community advantage from 14thd to the end of bioprocess in the normal system. The community structure of attached cells was greatly influenced in the free cells-deficient systems. Compared to A. thiooxidans, the attached cells community of Acidithiobacillus ferrooxidans had a higher dependence on its free cells. Meanwhile, the analysis of key biochemical parameters revealed that the effects of free cells on chalcopyrite bioleaching in different stages were diverse, ranging from 32.8% to 64.3%. The bioleaching contribution of free cells of A. ferrooxidans in the stationary stage (8-14thd) was higher than those of A. thiooxidans, while the situation was gradually reversed in the jarosite passivation inhibited stage (26-40thd). These results may be useful in guiding chalcopyrite bioleaching. Copyright © 2015 Elsevier Ltd. All rights reserved.

The potential of amino acids in alkaliphilic bioleaching

Energy Technology Data Exchange (ETDEWEB)

Barthen, Robert; Karimzadeh, Lotfallah; Gruendig, Marion; Franke, Karsten; Lippmann-Pipke, Johanna [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactive Transport; Heim, J. [Technische Univ. Bergakademie Freiberg (Germany)

2017-06-01

Bioleaching has become a major production process for copper contributing currently to around 15 % of the world wide copper production. However, non-sulfidic and/or complex ores are still not efficiently minable by conventional methods. In this study, we investigated the effect of copper complexing molecules such as amino acids on Cu{sup 2+} and S{sup 2-} solubilization from covellite.

Responses of microbial community to pH stress in bioleaching of low grade copper sulfide.

Science.gov (United States)

Wang, Yuguang; Li, Kai; Chen, Xinhua; Zhou, Hongbo

2018-02-01

The microbial diversity and dynamics in the leachates and on the ore surfaces of different depth of the column were analyzed during bioleaching of low grade copper sulfide at different pH, after inoculation with the same inoculum containing mesophiles and moderate thermophiles. The results indicate that low pH was beneficial to enhance copper extraction. The highest copper extraction (86%) was obtained when pH was controlled at 1.0-1.5. The microbial structures on the ore surfaces were independent of community structures in the leachate, even at the top portion of column. Microbial richness and evenness increased with decreasing pH during bioleaching. pH had significant effects on microbial community structure in the leachate and on the mineral surface of different depth of the column. Leptospirillum ferriphilum accounted for the highest proportions of the community at most times when pH was operated during bioleaching, especially at the end of run. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sulfobacillus benefaciens sp. nov., an acidophilic facultative anaerobic Firmicute isolated from mineral bioleaching operations.

Science.gov (United States)

Johnson, D Barrie; Joulian, Catherine; d'Hugues, Patrick; Hallberg, Kevin B

2008-11-01

Gram-positive bacteria found as the sole Firmicutes present in two mineral bioleaching stirred tanks, and a third bacterium isolated from a heap leaching operation, were shown to be closely related to each other but distinct from characterized acidophilic iron- and sulfur-oxidizing bacteria of the genus Sulfobacillus, to which they were affiliated. One of the isolates (BRGM2) was shown to be a thermo-tolerant (temperature optimum 38.5 degrees C, and maximum 47 degrees C) obligate acidophile (pH optimum 1.5, and minimum 0.8), and also noted to be a facultative anaerobe, growing via ferric iron respiration in the absence of oxygen. Although isolates BRGM2 and TVK8 were able to metabolize many monomeric organic substrates, their propensity for autotrophic growth was found to be greater than that of Sulfobacillus thermosulfidooxidans and the related acidophile, Sb. acidophilus. Faster growth rates of the novel isolates in the absence of organic carbon was considered to be a major reason why they, rather than Sb. thermosulfidooxidans (which shared many physiological characteristics) more successfully exploited conditions in the stirred tanks. Based on their phylogenetic and phenotypic characteristics, the isolates are designated strains of the proposed novel species, Sulfobacillus benefaciens, with isolate BRGM2 nominated as the type strain.

Study of bioleaching under different hydraulic retention time for enhancing the dewaterability of digestate.

Science.gov (United States)

Li, Linshuai; Gao, Jingqing; Zhu, Songfeng; Li, Yonghong; Zhang, Ruiqin

2015-12-01

Dewatering of kitchen waste digestate is a key problem to solve so as to increase the application of kitchen waste after anaerobic digestion. In this study, the effects of bioleaching under different hydraulic retention time (HRT = 2, 2.5, and 3 days) on dewaterability of kitchen waste digestate were evaluated. A 12-stage plug flow bioreactor with 180 L working volume was used for digestate bioleaching. The bioleached digestate under different HRTs were collected and dewatered by plate-and-frame filter press. The results showed that the moisture contents of digestate cakes were 67.87 % at 2 days of HRT, 58.06 % at 2.5 days of HRT, and 54.45 % at 3 days of HRT, respectively, indicating the longer the HRT, the lower the moisture content of filter cake. Balanced between the cost and practical need, 2.5 days can be used as the HRT in engineering application. Under the condition of HRT of 2.5 days, the pH, specific resistance to filtration (SRF), capillary suction time (CST), and sedimentation rate of digestate changed from the initial values of 8.08, 210.6 s, 23.4 × 10(12) m kg(-1) and 10 % to 3.21, 32.7 s, 2.44 × 10(12) m kg(-1) and 76.8 %, respectively. Based on the observations above, the authors conclude that bioleaching technology is an effective method to enhance digestate dewaterability and reduce the cost of subsequent reutilization.

Seed-vectored endophytic bacteria modulate development of rice seedlings.

Science.gov (United States)

Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

2017-06-01

The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains

Directory of Open Access Journals (Sweden)

Jorge Enrique Madrigal-Arias

2015-09-01

Full Text Available In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE, this research evaluated the bioleaching efficiency of gold (Au, copper (Cu and nickel (Ni by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs and cellular phone printed circuit boards (PCBs. These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains.

Science.gov (United States)

Madrigal-Arias, Jorge Enrique; Argumedo-Delira, Rosalba; Alarcón, Alejandro; Mendoza-López, Ma Remedios; García-Barradas, Oscar; Cruz-Sánchez, Jesús Samuel; Ferrera-Cerrato, Ronald; Jiménez-Fernández, Maribel

2015-01-01

In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

Combination of bioleaching by gross bacterial biosurfactants and flocculation: A potential remediation for the heavy metal contaminated soils.

Science.gov (United States)

Yang, Zhihui; Shi, Wei; Yang, Weichun; Liang, Lifen; Yao, Wenbin; Chai, Liyuan; Gao, Shikang; Liao, Qi

2018-09-01

Combining bioleaching by the gross biosurfactants of Burkholderia sp. Z-90 and flocculation by poly aluminium chloride (PAC) was proposed to develop a potential environment-friendly and cost-effective technique to remediate the severely contaminated soils by heavy metals. The factors affecting soil bioleaching by the gross biosurfactants of Burkholderia sp. Z-90 were optimized. The results showed the optimal removing efficiencies of Zn, Pb, Mn, Cd, Cu, and As by the Burkholderia sp. Z-90 leachate were 44.0, 32.5, 52.2, 37.7, 24.1 and 31.6%, respectively at soil liquid ratio of 1:20 (w/v) for 5 d, which were more efficient than that by 0.1% of rhamnolipid. The amounts of the bioleached heavy metals by the Burkholderia sp. Z-90 leachate were higher than that by other biosurfactants in the previous studies, although the removal efficiencies of the metals by the leachate were relatively lower. It was suggested that more heavy metals caused more competitive to chelate with function groups of the gross biosurfactants and the metal removal efficiencies by biosurfactants in natural soils were lower than in the artificially contaminated soils. Moreover, the Burkholderia sp. Z-90 leachate facilitated the metals to be transformed to the easily migrating speciation fractions. Additional, the results showed that PAC was efficient in the following flocculation to remove heavy metals in the waste bio-leachates. Our study will provide support for developing a bioleaching technique model to remediate the soils extremely contaminated by heavy metals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Metagenome-scale analysis yields insights into the structure and function of microbial communities in a copper bioleaching heap.

Science.gov (United States)

Zhang, Xian; Niu, Jiaojiao; Liang, Yili; Liu, Xueduan; Yin, Huaqun

2016-01-19

Metagenomics allows us to acquire the potential resources from both cultivatable and uncultivable microorganisms in the environment. Here, shotgun metagenome sequencing was used to investigate microbial communities from the surface layer of low grade copper tailings that were industrially bioleached at the Dexing Copper Mine, China. A bioinformatics analysis was further performed to elucidate structural and functional properties of the microbial communities in a copper bioleaching heap. Taxonomic analysis revealed unexpectedly high microbial biodiversity of this extremely acidic environment, as most sequences were phylogenetically assigned to Proteobacteria, while Euryarchaeota-related sequences occupied little proportion in this system, assuming that Archaea probably played little role in the bioleaching systems. At the genus level, the microbial community in mineral surface-layer was dominated by the sulfur- and iron-oxidizing acidophiles such as Acidithiobacillus-like populations, most of which were A. ferrivorans-like and A. ferrooxidans-like groups. In addition, Caudovirales were the dominant viral type observed in this extremely environment. Functional analysis illustrated that the principal participants related to the key metabolic pathways (carbon fixation, nitrogen metabolism, Fe(II) oxidation and sulfur metabolism) were mainly identified to be Acidithiobacillus-like, Thiobacillus-like and Leptospirillum-like microorganisms, indicating their vital roles. Also, microbial community harbored certain adaptive mechanisms (heavy metal resistance, low pH adaption, organic solvents tolerance and detoxification of hydroxyl radicals) as they performed their functions in the bioleaching system. Our study provides several valuable datasets for understanding the microbial community composition and function in the surface-layer of copper bioleaching heap.

Metallic ions catalysis for improving bioleaching yield of Zn and Mn from spent Zn-Mn batteries at high pulp density of 10.

Science.gov (United States)

Niu, Zhirui; Huang, Qifei; Wang, Jia; Yang, Yiran; Xin, Baoping; Chen, Shi

2015-11-15

Bioleaching of spent batteries was often conducted at pulp density of 1.0% or lower. In this work, metallic ions catalytic bioleaching was used for release Zn and Mn from spent ZMBs at 10% of pulp density. The results showed only Cu(2+) improved mobilization of Zn and Mn from the spent batteries among tested four metallic ions. When Cu(2+) content increased from 0 to 0.8 g/L, the maximum release efficiency elevated from 47.7% to 62.5% for Zn and from 30.9% to 62.4% for Mn, respectively. The Cu(2+) catalysis boosted bioleaching of resistant hetaerolite through forming a possible intermediate CuMn2O4 which was subject to be attacked by Fe(3+) based on a cycle of Fe(3+)/Fe(2+). However, poor growth of cells, formation of KFe3(SO4)2(OH)6 and its possible blockage between cells and energy matters destroyed the cycle of Fe(3+)/Fe(2+), stopping bioleaching of hetaerolite. The chemical reaction controlled model fitted best for describing Cu(2+) catalytic bioleaching of spent ZMBs. Copyright © 2015 Elsevier B.V. All rights reserved.

Bioleaching of Arsenic-Rich Gold Concentrates by Bacterial Flora before and after Mutation

Directory of Open Access Journals (Sweden)

Xuehui Xie

2013-01-01

Full Text Available In order to improve the bioleaching efficiency of arsenic-rich gold concentrates, a mixed bacterial flora had been developed, and the mutation breeding method was adopted to conduct the research. The original mixed bacterial flora had been enrichedin acid mine drainage of Dexing copper mine, Jiangxi Province, China. It was induced by UV (ultraviolet, ultrasonic, and microwave, and their combination mutation. The most efficient bacterial flora after mutation was collected for further bioleaching of arsenic-rich gold concentrates. Results indicated that the bacterial flora after mutation by UV 60 s combined with ultrasonic 10 min had the best oxidation rate of ferrous, the biggest density of cells, and the most activity of total protein. During bioleaching of arsenic-rich gold concentrates, the density of the mutant bacterial cells reached to 1.13×108 cells/mL at 15 days, more than 10 times compared with that of the original culture. The extraction of iron reached to 95.7% after 15 days, increased by 9.9% compared with that of the original culture. The extraction of arsenic reached to 92.6% after 12 days, which was increased by 46.1%. These results suggested that optimum combined mutation could improve leaching ability of the bacterial flora more significantly.

Bioleaching of Arsenic-Rich Gold Concentrates by Bacterial Flora before and after Mutation

Science.gov (United States)

Xie, Xuehui; Yuan, Xuewu; Liu, Na; Chen, Xiaoguang; Abdelgadir, Awad; Liu, Jianshe

2013-01-01

In order to improve the bioleaching efficiency of arsenic-rich gold concentrates, a mixed bacterial flora had been developed, and the mutation breeding method was adopted to conduct the research. The original mixed bacterial flora had been enrichedin acid mine drainage of Dexing copper mine, Jiangxi Province, China. It was induced by UV (ultraviolet), ultrasonic, and microwave, and their combination mutation. The most efficient bacterial flora after mutation was collected for further bioleaching of arsenic-rich gold concentrates. Results indicated that the bacterial flora after mutation by UV 60 s combined with ultrasonic 10 min had the best oxidation rate of ferrous, the biggest density of cells, and the most activity of total protein. During bioleaching of arsenic-rich gold concentrates, the density of the mutant bacterial cells reached to 1.13 × 108 cells/mL at 15 days, more than 10 times compared with that of the original culture. The extraction of iron reached to 95.7% after 15 days, increased by 9.9% compared with that of the original culture. The extraction of arsenic reached to 92.6% after 12 days, which was increased by 46.1%. These results suggested that optimum combined mutation could improve leaching ability of the bacterial flora more significantly. PMID:24381948

Isolation of Indigenous Bacteria of Phosphate Solubilizing from Green Bean Rhizospheres

Directory of Open Access Journals (Sweden)

N Arfarita

2017-04-01

Full Text Available The use of phosphate-solubilizing bacteria (PSB as a biological fertilizer of Agricultural land is one solution to overcome problem of phosphate availability for plants. However, often application of a biological fertilizer is ineffective for certain places. The purpose of this study was to obtain indigenous phosphate solubilizing bacterial isolates that can be effective in the area of Malang. Samples were collected from rhizosphereof green bean plants at three locations in Malang, East Java. The study was conducted to determine the total bacterial population of soil samples, to select the best three bacterial isolates in phosphate solubilizing ability, which is not antagonistic and nonpathogenic for plants,along with observing its potential as a bacterial consortium. The highest total population was found in FHR samples of 1.5x1011 CFU / mL. We have selected three bacterial isolates namely SPP1, SPP2 and SPP3. They were not antagonistic to each other and nonpathogenic on mungbean sprouts. They had possibility of producing growth hormone which characterized by an increasing in length of plant and total root length, be compared to controls. Strain SPP2 has shown the highest activity of phosphate solubilization then was selected for 16S rRNA identification. Similarity test of genome sequence of strain SPP2 had 99% similarity with Pseudomonas plecoglossicida strain PR19

Biochar addition for accelerating bioleaching of heavy metals from swine manure and reserving the nutrients.

Science.gov (United States)

Wei, Xiaocheng; Liu, Dongfang; Li, Wenjiao; Liao, Lirui; Wang, Zhendong; Huang, Weiwei; Huang, Wenli

2018-08-01

Biochar was applied during the bioleaching of heavy metals (HMs) from swine manure (SM), in an attempt to accelerate the HMs removal rates and to reduce the losses of nutrient elements (nitrogen and phosphorus). Results showed that the addition of biochar (5gL -1 ) could not only significantly shorten the leaching time of HMs (Cu, Zn, Mn and Cd) from 10 (control) to 7days with a high solubilization efficiency of 90%, but also decrease the total nitrogen loss efficiency by 42.7% from 180.3 (control) to 103.3mgL -1 in the leachate. In addition, biochar addition facilitated Fe 2+ oxidation rate, achieving much better pH and ORP conditions. Electronic conductivity and adsorption properties of biochar with changed microbial community probably contributed a lot to the enhanced HMs solubilization and reduced nitrogen loss during bioleaching. Although the addition of biochar only slightly reduced the total amount of phosphorus loss, the bioavailable phosphorus in SM after bioleaching was markedly increased by 13.7%. Copyright © 2018 Elsevier B.V. All rights reserved.

Novel integration strategy for enhancing chalcopyrite bioleaching by Acidithiobacillus sp. in a 7-L fermenter.

Science.gov (United States)

Feng, Shoushuai; Yang, Hailin; Zhan, Xiao; Wang, Wu

2014-06-01

An integrated strategy (additional energy substrate-three stage pH control-fed batch) was firstly proposed for efficiently improving chalcopyrite bioleaching by Acidithiobacillus sp. in a 7-L fermenter. The strain adaptive-growing phase was greatly shortened from 8days into 4days with the supplement of additional 2g/L Fe(2+)+2g/L S(0). Jarosite passivation was effectively weakened basing on higher biomass via the three-stage pH-stat control (pH 1.3-1.0-0.7). The mineral substrate inhibition was attenuated by fed-batch fermentation. With the integrated strategy, the biochemical reaction was promoted and achieved a better balance. Meanwhile, the domination course of A. thiooxidans in the microbial community was shortened from 14days to 8days. As the results of integrated strategy, the final copper ion and productivity reached 89.1mg/L and 2.23mg/(Ld), respectively, which was improved by 52.8% compared to the uncontrolled batch bioleaching. The integrated strategy could be further exploited for industrial chalcopyrite bioleaching. Copyright © 2014 Elsevier Ltd. All rights reserved.

Underground bioleaching: extracting from low-grade ore

International Nuclear Information System (INIS)

McCready, R.G.L.

1986-01-01

In 1984, Denison Mines began a research and demonstration project on the engineering aspects of bacterial leaching of low-grade uranium ore at Elliot Lake. The leaching solution was acidic mine water enriched in bacterial nutrients and innoculated with Thiobacillus ferrooxidans. Leaching of one stope was found to be impeded by fungi of the genus penicillium. Although fungal growth on leaching stopes must be prevented, research is proceeding on the potential use of the fungi to concentrate uranium from bioleaching solutions

A Review of the Application of Ultrasound in Bioleaching and Insights from Sonication in (BioChemical Processes

Directory of Open Access Journals (Sweden)

Shruti Vyas

2017-12-01

Full Text Available Chemical and biological leaching is practiced on a commercial scale for the mining of metals from ores. Although bioleaching is an environmentally-friendly alternative to chemical leaching, one of the principal shortcomings is the slow rate of leaching which needs to be addressed. The application of ultrasound in bioleaching, termed sonobioleaching, is a technique which has been reported to increase the rate and extent of metal extraction. This article reviews efforts made in the field of sonobioleaching. Since bioleaching is effectively a biological and chemical process, the effects of sonication on chemical leaching/reactions and biological processes are also reviewed. Although sonication increases metal extraction by increasing the metabolite production and enhanced mixing at a micro scale, research is limited in terms of the microorganisms explored. This paper highlights some shortcomings and limitations of existing techniques, and proposes directions for future research.

Modelling a uranium ore bioleaching process

International Nuclear Information System (INIS)

Chien, D.C.H.; Douglas, P.L.; Herman, D.H.; Marchbank, A.

1990-01-01

A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobacillus ferroxidans present in the leaching solution and transport properties. Model predictions agree well with experimental data with an average deviation of about ± 3%. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information

Fungal bioleaching of WPCBs using Aspergillus niger: Observation, optimization and kinetics.

Science.gov (United States)

Faraji, Fariborz; Golmohammadzadeh, Rabeeh; Rashchi, Fereshteh; Alimardani, Navid

2018-07-01

In this study, Aspergillus niger (A. niger) as an environmentally friendly agent for fungal bioleaching of waste printed circuit boards (WPCBs) was employed. D-optimal response surface methodology (RSM) was utilized for optimization of the bioleaching parameters including bioleaching method (one step, two step and spent medium) and pulp densities (0.5 g L -1 to 20 g L -1 ) to maximize the recovery of Zn, Ni and Cu from WPCBs. According to the high performance liquid chromatography analysis, citric, oxalic, malic and gluconic acids were the most abundant organic acids produced by A.niger in 21 days experiments. Maximum recoveries of 98.57% of Zn, 43.95% of Ni and 64.03% of Cu were achieved based on acidolysis and complexolysis dissolution mechanisms of organic acids. Based on the kinetic studies, the rate controlling mechanism for Zn dissolution at one step approach was found to be diffusion through liquid film, while it was found to be mixed control for both two step and spent medium. Furthermore, rate of Cu dissolution which is controlled by diffusion in one step and two step approaches, detected to be controlled by chemical reaction at spent medium. It was shown that for Ni, the rate is controlled by chemical reaction for all the methods studied. Eventually, it was understood that A. niger is capable of leaching 100% of Zn, 80.39% of Ni and 85.88% of Cu in 30 days. Copyright © 2018 Elsevier Ltd. All rights reserved.

Optimization of staged bioleaching of low-grade chalcopyrite ore in the presence and absence of chloride in the irrigating lixiviant: ANFIS simulation.

Science.gov (United States)

Vakylabad, Ali Behrad; Schaffie, Mahin; Naseri, Ali; Ranjbar, Mohammad; Manafi, Zahra

2016-07-01

In this investigation, copper was bioleached from a low-grade chalcopyrite ore using a chloride-containing lixiviant. In this regard, firstly, the composition of the bacterial culture media was designed to control the cost in commercial application. The bacterial culture used in this process was acclimated to the presence of chloride in the lixiviant. Practically speaking, the modified culture helped the bio-heap-leaching system operate in the chloridic media. Compared to the copper recovery from the low-grade chalcopyrite by bioleaching in the absence of chloride, bioleaching in the presence of chloride resulted in improved copper recovery. The composition of the lixiviant used in this study was a modification with respect to the basal salts in 9 K medium to optimize the leaching process. When leaching the ore in columns, 76.81 % Cu (based on solid residues of bioleaching operation) was recovered by staged leaching with lixiviant containing 34.22 mM NaCl. The quantitative findings were supported by SEM/EDS observations, X-ray elemental mapping, and mineralogical analysis of the ore before and after leaching. Finally, Adaptive neuro-fuzzy inference system (ANFIS) was used to simulate the operational parameters affecting the bioleaching operation in chloride-sulfate system.

Specific aminopeptidases of indigenous Lactobacillus brevis and ...

African Journals Online (AJOL)

Lactic acid bacteria play an important role in milk coagulation and cheese ripening. To select strains showing interesting industrial features, two indigenous lactobacilli (Lactobacillus brevis and Lactobacillus plantarum) were studied for aminopeptidase activity. Cell and cells free extract were tested for leucyl aminopeptidase ...

Application of Reactive Transport Modeling to Heap Bioleaching of Copper

Science.gov (United States)

Liu, W.

2017-12-01

Copper heap bioleaching is a complex industrial process that utilizes oxidative chemical leaching and microbial activities to extract copper from packed ore beds. Mathematical modelling is an effective tool for identifying key factors that determine the leaching performance. HeapSim is a modelling tool that incorporates all fundamental processes that occur in a heap under leach, such as the movement of leaching solution, chemical reaction kinetics, heat transfer, and microbial activities, to predict the leaching behavior of a heap. In this study, the HeapSim model was applied to simulate chalcocite heap bioleaching at Quebrada Blanca mine located in the Northern Chile. The main findings were that the model could be satisfactorily calibrated and validated to simulate chalcocite leaching. Heap temperature was sensitive to the changes in the raffinate temperature, raffinate flow rate, and the extent of pyrite oxidation. At high flow rates, heap temperature was controlled by the raffinate temperature. In contrast, heat removal by the raffinate solution flow was insignificant at low flow rates, leading to the accumulation of heat generated by pyrite reaction and therefore an increase in heap temperature.

Arsenic tolerance and bioleaching from realgar based on response surface methodology by Acidithiobacillus ferrooxidans isolated from Wudalianchi volcanic lake, northeast China

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Lei Yan

2017-01-01

Conclusion: From this work we were successful in isolating an acidophilic, arsenic tolerant ferrous iron-oxidizing bacterium. The BBD-RSM analysis showed that maximum arsenic bioleaching rate obtained under optimum conditions, and the most effective factor for arsenic leaching was initial ferrous ion concentration. These revealed that BYQ-12 could be used for bioleaching of arsenic from arsenical minerals.

Analysis of metal Bioleaching from thermal power plant fly ash by Aspergillus niger 34770 culture supernatant and reduction of phytotoxicity during the process.

Science.gov (United States)

Jadhav, Umesh U; Hocheng, Hong

2015-01-01

Aspergillus niger culture supernatant is used for bioleaching process. Before starting bioleaching process, fly ash was washed with distilled water. This removed 100 % sodium, 47 % (±0.45) boron, 38.07 % (±0.12) calcium, 29.89 % (±0.78) magnesium, and 11.8 % (±0.05) potassium. The pH was reduced from 10.5 to 8.5 after water washing. During bioleaching process, around 100 % metal removal was achieved in 4 h for all metals except chromium 93 % (±1.18), nickel 83 % (±0.32), arsenic 78 % (±0.52), and lead 70 % (±0.20). The process parameters including temperature, shaking speed, and solid/liquid ratio were optimized for bioleaching process. Experiments were conducted to evaluate effect of fly ash on growth of mung bean (Vigna radiata). At 20 g/100 ml fly ash concentration no germination of V. radiata seeds was observed. With an increasing concentration of untreated fly ash, a gradual decrease in root/shoot length was observed. After bioleaching process 78 % (±0.19) germination of V. radiata was observed with 20 g/100 ml fly ash. This study will help to develop an efficient process to remove the toxic metals from fly ash.

Comparative study on the passivation layers of copper sulphide minerals during bioleaching

Science.gov (United States)

Fu, Kai-bin; Lin, Hai; Mo, Xiao-lan; Wang, Han; Wen, Hong-wei; Wen, Zi-long

2012-10-01

The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite>bornite>pyritic chalcopyrite>covellite>porphyry chalcopyrite. The residues were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is indicated that jarosite may not be responsible for hindered dissolution. The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked. The compact surface layer of porphyry chalcopyrite may strongly hinder copper extraction. X-ray photoelectron spectroscopy (XPS) further confirms that the passivation layers of covellite, pyritic chalcopyrite, and porphyry chalcopyrite are copper-depleted sulphide Cu4S11, S8, and copper-rich iron-deficient polysulphide Cu4Fe2S9, respectively. The ability of these passivation layers was found as Cu4Fe2S9>Cu4S11>S8>jarosite.

Bioleaching of trace metals from coal ash using local isolate from coal ash ponds

Directory of Open Access Journals (Sweden)

Pangayao Denvert

2018-01-01

Full Text Available Bioleaching of chromium, copper, manganese and zinc from coal ash were investigated using isolates from coal ash ponds particularly Psuedomonas spp. Six (6 different coal ash ponds were examined however, after initial screening Psuedomonas spp. were only present in three (3 coal ash ponds. Among the three coal ash ponds, results showed that eight (8 putative Pseudomonas spp. isolates were present that were identified using the Polymerase Chain Reaction (PCR. Using the eight putative Pseudomonas spp. for bioleaching at optimum conditions and 15 days, the pH value ranges from 8.26 to 8.84 which was basic in nature. Moreover, the maximum metal leached were 8.04% Cr, 12.05% Cu, 4.34% Mn and 10.63% Zn.

Fungal leaching of valuable metals from a power plant residual ash using Penicillium simplicissimum: Evaluation of thermal pretreatment and different bioleaching methods.

Science.gov (United States)

Rasoulnia, P; Mousavi, S M; Rastegar, S O; Azargoshasb, H

2016-06-01

Each year a tremendous volume of V-Ni rich ashes is produced by fuel oil consuming power plants throughout the world. Recovery of precious metals existing in these ashes is very important from both economic and environmental aspects. The present research was aimed at investigating bioleaching potential of Penicillium simplicissimum for the recovery of metals from power plant residual ash (PPR ash) using different bioleaching methods such as one-step, two-step, and spent-medium bioleaching at 1% (w/v) pulp density. Furthermore, the effects of thermal pretreatment on leaching of V, Ni, and Fe, as major elements present in PPR ash, were studied. Thermal pretreatment at various temperatures removed the carbonaceous and volatile fraction of the ash and affected the fungal growth and metal leachability. The highest extraction yields of V and Ni were achieved for the original PPR ash, using spent-medium bioleaching in which nearly 100% of V and 40% of Ni were extracted. The maximum extraction yield of Fe (48.3%) was obtained for the pretreated PPR ash at 400°C by spent-medium bioleaching. In addition, the fungal growth in pure culture was investigated through measurement of produced organic acids via high performance liquid chromatography (HPLC). Chemical leaching experiments were performed, using commercial organic acids at the same concentrations as those produced under optimum condition of fungal growth (5237ppm citric, 3666ppm gluconic, 1287ppm oxalic and 188ppm malic acid). It was found that in comparison to chemical leaching, bioleaching improved V and Ni recovery up to 19% and 12%, respectively. Moreover, changes in physical and chemical properties as well as morphology of the samples utilizing appropriate analytical methods such as XRF, XRD, FTIR, and FE-SEM were comprehensively investigated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of operating parameters and rate of uranium bioleaching from a low-grade ore

International Nuclear Information System (INIS)

Rashidi, A.; Roosta-Azad, R.; Safdari, S.J.

2014-01-01

In this study the bioleaching of a low-grade uranium ore containing 480 ppm uranium has been reported. The studies involved extraction of uranium using Acidithiobacillus ferrooxidans derived from the uranium mine samples. The maximum specific growth rate (μ max ) and doubling time (t d ) were obtained 0.08 h -1 and 8.66 h, respectively. Parameters such as Fe 2+ concentration, particle size, temperature and pH were optimized. The effect of pulp density (PD) was also studied. Maximum uranium bio-dissolution of 100 ± 5 % was achieved under the conditions of pH 2.0, 5 % PD and 35 deg C in 48 h with the particles of d 80 = 100 μm. The optimum concentration of supplementary Fe 2+ was dependent to the PD. This value was 0 and 10 g of FeSO 4 ·7H 2 O/l at the PD of 5 and 15 %, respectively. The effects of time, pH and PD on the bioleaching process were studied using central composite design. New rate equation was improved for the uranium leaching rate. The rate of leaching is controlled with the concentrations of ferric and ferrous ions in solution. This study shows that uranium bioleaching may be an important process for the Saghand U mine at Yazd (Iran). (author)

Influence of acidified acidity to uranium bioleaching

International Nuclear Information System (INIS)

Li Jiang; Liu Yajie; Zheng Zhihong; Yuan Baohua; Shen Chuan; Shi Weijun

2012-01-01

The relationship between the acidified acidity and the acid consumption and uranium leaching rate in the process of uranium bioleaching is investigated. Results indicate that higher uranium leaching rate is obtained when the relatively high acidity was applied at beginning. For different minerals, although the original acidity should be different, lower original acidity was not better for shortening leaching period and improving uranium leaching rate. It confirms 30-40 g/L sulfuric acid as the original acidity was more suitable and more than 30 g/ L should be applied if the mineral particle sizes were larger. (authors)

Mechanisms of bioleaching and the visualization of these by combined AFM & EFM

NARCIS (Netherlands)

Sand, W.; Florian, B.; Noël, N.

2009-01-01

The understanding of mechanisms, by which microorganisms are effecting the dissolution of metal sulfides, what in general is called bioleaching, has progressed largely during the last 15 years. Whereas in the beginning of the nineties of the last century the direct and the indirect mechanisms were

Expression of Critical Sulfur- and Iron-Oxidation Genes and the Community Dynamics During Bioleaching of Chalcopyrite Concentrate by Moderate Thermophiles.

Science.gov (United States)

Zhou, Dan; Peng, Tangjian; Zhou, Hongbo; Liu, Xueduan; Gu, Guohua; Chen, Miao; Qiu, Guanzhou; Zeng, Weimin

2015-07-01

Sulfate adenylyltransferase gene and 4Fe-4S ferredoxin gene are the key genes related to sulfur and iron oxidations during bioleaching system, respectively. In order to better understand the bioleaching and microorganism synergistic mechanism in chalcopyrite bioleaching by mixed culture of moderate thermophiles, expressions of the two energy metabolism genes and community dynamics of free and attached microorganisms were investigated. Specific primers were designed for real-time quantitative PCR to study the expression of these genes. Real-time PCR results showed that sulfate adenylyltransferase gene was more highly expressed in Sulfobacillus thermosulfidooxidans than that in Acidithiobacillus caldus, and expression of 4Fe-4S ferredoxin gene was higher in Ferroplasma thermophilum than that in S. thermosulfidooxidans and Leptospirillum ferriphilum. The results indicated that in the bioleaching system of chalcopyrite concentrate, sulfur and iron oxidations were mainly performed by S. thermosulfidooxidans and F. thermophilum, respectively. The community dynamics results revealed that S. thermosulfidooxidans took up the largest proportion during the whole period, followed by F. thermophilum, A. caldus, and L. ferriphilum. The CCA analysis showed that 4Fe-4S ferredoxin gene expression was mainly affected (positively correlated) by high pH and elevated concentration of ferrous ion, while no factor was observed to prominently influence the expression of sulfate adenylyltransferase gene.

Tolerance of Chemoorganotrophic Bioleaching Microorganisms to Heavy Metal and Alkaline Stresses

Science.gov (United States)

Monballiu, Annick; Cardon, Nele; Tri Nguyen, Minh; Cornelly, Christel; Meesschaert, Boudewijn; Chiang, Yi Wai

2015-01-01

The bioleaching potential of the bacterium Bacillus mucilaginosus and the fungus Aspergillus niger towards industrial residues was investigated by assessing their response towards various heavy metals (including arsenic, cadmium, cobalt, chromium, nickel, lead, and zinc) and elevated pH. The plate diffusion method was performed for each metal to determine the toxicity effect. Liquid batch cultures were set up for more quantitative evaluation as well as for studying the influence of basicity. Growth curves were prepared using bacterial/fungal growth counting techniques such as plate counting, optical density measurement, and dry biomass determination. Cadmium, nickel, and arsenite had a negative influence on the growth of B. mucilaginosus, whereas A. niger was sensitive to cadmium and arsenate. However, it was shown that growth recovered when microorganisms cultured in the presence of these metals were inoculated onto metal-free medium. Based on the findings of the bacteriostatic/fungistatic effect of the metals and the adaptability of the microorganisms to fairly elevated pH values, it is concluded that both strains have potential applicability for further research concerning bioleaching of alkaline waste materials. PMID:26236176

Evaluation of hydrocarbons level and identification of indigenous ...

African Journals Online (AJOL)

Evaluation of hydrocarbons level and identification of indigenous bacteria in soil from auto-mechanic workshops along Ikokwu Mechanic Village, Port Harcourt, ... (ii) it is essential that the metagenomics of spent engine oil contaminated soil at auto-mechanic workshop be studied for optimum utilization of their potentials.

Column bioleaching of arsenic and Heavy metals from gold mine tailings by aspergillus fumigatus

International Nuclear Information System (INIS)

Seh-Bardan, Bahi Jalili; Othman, Radziah; Ab Wahid, Samsuri; Husin, Aminudin; Sadegh-Zadeh, Fardin

2012-01-01

A column bioleaching experiment was carried out to compare the effectiveness of the fungus Aspergillus fumigatus to bioleach arsenic (As) and heavy metals from the tailings using two different methods. In the first method, which is named as distribution method (DM), the fungus was distributed in the column by means of vertical and horizontal layers of coarse sand. In the other method, named as surface applied method (SAM), the fungus was cultivated on the surface of the tailings, which was covered with a few centimeters of coarse sand. Results showed that in the DM, oxalic acid production was stimulated and maximum removal of As, Fe, Mn, and Zn was 53, 51, 81, and 62%, respectively. However, Pb removal was low (8%), which might be due to the precipitation of Pb as its oxalates. On the other hand, the maximum removal of As, Fe, Mn, Pb, and Zn were 22, 28, 37, 64, and 34%, respectively, for the SAM. Results of the sequential extraction study showed that the DM was effective in removing the water soluble, exchangeable, carbonate, and Fe/Mn oxide fractions of As, Fe, Mn, and Zn. Our study suggested that A. fumigatus has a potential to be used in remediation of heavy metal contaminated sites. Distributing the fungus throughout the entire tailings columns improved the bioleaching of heavy metals by the fungus. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Column bioleaching of arsenic and Heavy metals from gold mine tailings by aspergillus fumigatus

Energy Technology Data Exchange (ETDEWEB)

Seh-Bardan, Bahi Jalili; Othman, Radziah; Ab Wahid, Samsuri; Husin, Aminudin; Sadegh-Zadeh, Fardin [Faculty of Agriculture, Department of Land Management, Universiti Putra Malaysia, Serdang, Selangor (Malaysia)

2012-06-15

A column bioleaching experiment was carried out to compare the effectiveness of the fungus Aspergillus fumigatus to bioleach arsenic (As) and heavy metals from the tailings using two different methods. In the first method, which is named as distribution method (DM), the fungus was distributed in the column by means of vertical and horizontal layers of coarse sand. In the other method, named as surface applied method (SAM), the fungus was cultivated on the surface of the tailings, which was covered with a few centimeters of coarse sand. Results showed that in the DM, oxalic acid production was stimulated and maximum removal of As, Fe, Mn, and Zn was 53, 51, 81, and 62%, respectively. However, Pb removal was low (8%), which might be due to the precipitation of Pb as its oxalates. On the other hand, the maximum removal of As, Fe, Mn, Pb, and Zn were 22, 28, 37, 64, and 34%, respectively, for the SAM. Results of the sequential extraction study showed that the DM was effective in removing the water soluble, exchangeable, carbonate, and Fe/Mn oxide fractions of As, Fe, Mn, and Zn. Our study suggested that A. fumigatus has a potential to be used in remediation of heavy metal contaminated sites. Distributing the fungus throughout the entire tailings columns improved the bioleaching of heavy metals by the fungus. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Bioleaching of Primary Nickel Ore Using Acidithiobacillus ferrooxidans LR Cells Immobilized in Glass Beads

Directory of Open Access Journals (Sweden)

Ellen Cristine Giese

2015-06-01

Full Text Available Sulphide minerals are one of the most important sources of value metals. For several years, a large number of hydrometallurgical and biotechnological processes have been developed to leach low-grade sulphide ores and the conditions are well established. However, the management of microorganisms in the bioleaching process is not easy to handle. In this paper, the use of immobilized cells of Acidithiobacillus ferrooxidans LR in glass beads in bioleaching of primary nickel ore was evaluated. The column experiments inoculated with immobilized cells of A. ferrooxidans LR showed the same efficiency than the conventional method using free cells and is promising for application on a larger scale as it ensuring integrity and activity of biomining microorganisms and reduce process costs. DOI: http://dx.doi.org/10.17807/orbital.v7i2.698 

Biodesulfurization of vanadium-bearing titanomagnetite concentrates and pH control of bioleaching solution

Science.gov (United States)

Liu, Xiao-rong; Jiang, Sheng-cai; Liu, Yan-jun; Li, Hui; Wang, Hua-jun

2013-10-01

Vanadium-bearing titanomagnetite concentrates were desulfurized with Acidithiobacillus ferrooxidans ( A. ferrooxidans). The sulfur content of the concentrates was reduced from 0.69wt% to 0.14wt% after bioleaching for 15 d with a 10% pulp density at 30°C. Maintaining a stable pH value during biodesulfurization was critical because of high acid consumption, resulting from a combination of nonoxidative and oxidative dissolution of pyrrhotite in acid solution. It is discovered that the citric acid-disodium hydrogen phosphate buffer of pH 2.0 can control the solution pH value smoothly in the optimal range of 2.0-3.0 for A. ferrooxidans growth. Using the buffer in the volume fraction range of 5.0%-15.0% stimulates A. ferrooxidans growth and improves the biodesulfurization efficiency. Compared with the buffer-free control case, the maximum increase of biodesulfurization rate is 29.7% using a 10.0vol% buffer. Bioleaching provides an alternative process for desulfurization of vanadium-bearing titanomagnetite ores.

The Bacteria Quality Of The Indigenously Fermented Milk Product ...

African Journals Online (AJOL)

Fifty samples of 'nono', a fermented milk product akin to yoghurt, were carefully collected from three markets in Maiduguri municipality, and were examined for the presence of pathogenic bacteria. Twenty-eight percent of the samples were found to be contaminated with aciduric pathogenic bacteria that may cause ...

[Application of immunologic methods to the analysis of bio-leaching bacteria].

Science.gov (United States)

Coto, O; Fernández, A I; León, T; Rodríguez, D

1994-09-01

Pure cultures of Thiobacillus ferrooxidans and mixed cultures of Thiobacillus ferrooxidans and Leptospirillum ferrooxidans isolated from the Matahambre mine (Cuba) were used to fit immunodiffusion and immunoelectron microscopy to the study of iron oxidizing bacteria. The possibilities, advantages and limits of those techniques have been studied from both the identification and the serological characterization points of view. Finally, the efficiency of these methods was tested by applying them to the identification of microorganisms from acidic waters from the mine.

Bioleaching of electronic scrap by mixed culture of moderately thermophilic microorganisms

Science.gov (United States)

Ivǎnuş, D.; ǎnuş, R. C., IV; Cǎlmuc, F.

2010-06-01

A process for the metal recovery from electronic scrap using bacterial leaching was investigated. A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages (AMDs) samples collected from several sulphide mines in Romania, and the bioleaching of electronic scrap was conducted both in shake flask and bioreactor. The results show that in the shake flask, the mixture can tolerate 50 g/L scrap after being acclimated to gradually increased concentrations of scrap. The copper extraction increases obviously in bioleaching of scrap with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min, 74% copper can be extracted in the pulp of 50 g/L scrap after 20 d. Compared with copper extractions of mesophilic culture, unacclimated culture and acclimated culture without addition of yeast extract, that of accliniated culture with addition of yeast extract is increased by 53%, 44% and 16%, respectively. In a completely stirred tank reactor, the mass fraction of copper and total iron extraction reach up to 81% and 56%, respectively. The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from electronic scrap effectively.

BIOREMEDIATION OF CONTAMINATED WASTE BY CADMIUM (Cd) IN WATERS USING INDIGEN BACTERIUM WITH EX-SITU WAY

OpenAIRE

Titik Wijayanti; Dinna Eka Graha Lestari

2017-01-01

The bioremediation technique for a contaminated liquid waste of heavy metals using indigenous bacteria is a convenient alternative to steps continues to be developed. The research aims to find out the effectiveness of an indigenous bacterial consortium in bioremediation of contaminated liquid waste by cadmium by ex-situ. Experiments were arranged in RAL made in ex-situ where a liquid waste industry was given five treatments, namely control and four indigenous bacterial consortia (A, D, E, and...

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains and microbial community succession analysis

Science.gov (United States)

Hao, Xiao-dong; Liang, Yi-li; Yin, Hua-qun; Liu, Hong-wei; Zeng, Wei-min; Liu, Xue-duan

2017-04-01

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains was carried out by mixed cultures on a small scale over a period of 210 d. Lump ores as a framework were loaded at the bottom of the ore heap. The overall copper leaching rates of tailings and lump ores were 57.10wt% and 65.52wt%, respectively. The dynamic shifts of microbial community structures about attached microorganisms were determined using the Illumina MiSeq sequencing platform based on 16S rRNA amplification strategy. The results indicated that chemolithotrophic genera Acidithiobacillus and Leptospirillum were always detected and dominated the microbial community in the initial and middle stages of the heap bioleaching process; both genera might be responsible for improving the copper extraction. However, Thermogymnomonas and Ferroplasma increased gradually in the final stage. Moreover, the effects of various physicochemical parameters and microbial community shifts on the leaching efficiency were further investigated and these associations provided some important clues for facilitating the effective application of bioleaching.

Bioleaching of a manganese and silver Ore

International Nuclear Information System (INIS)

Porro, S.; Tedesco, P.H.; La Plata

1990-01-01

The bioleaching with a strain of Thiobacillus thiooxidans of the ore of Farallon Negro (Catamarca, Argentina) was studied in order to estimate its application to the solution and recovery of the manganese, and to improve the silver extraction. The State company which works the mine has not yet found an economical process to extract the manganese and has only reached a 30% efficiency in the recovery of silver by cianuration. The effects of pulp density variations and the addition of different quantities of FeS were analysed looking for the best working conditions. 74 μm (mesh Tyler 200) of ore particles were used because that is the size used in this plant for the cianuration process. (Author)

Bioleaching of heavy metal polluted sediment: kinetics of leaching and microbial sulfur oxidation

Energy Technology Data Exchange (ETDEWEB)

Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebenmitteltechnik und Bioverfahrenstechnik, D-01062 Dresden (Germany); Zehnsdorf, A. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Umwelt- und Biotechnologisches Zentrum (UBZ), Permoserstrasse 15, D-04318 Leipzig (Germany); Goersch, K.; Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany)

2005-12-01

Remediation of heavy metal polluted sediment through bioleaching using elemental sulfur (S{sup 0}) as the leaching agent can be regarded as a two-step process: firstly, the microbial oxidation of the added S{sup 0} to sulfuric acid and, secondly, the reaction of the produced acid with the sediment. Here, both subprocesses were studied in detail independently: oxidized river sediment was either suspended in sulfuric acid of various strengths, or mixed with various amounts of finely ground S{sup 0} powder (diameter of the S{sup 0} particles between 1 and 175 {mu}m with a Rosin-Rammler-Sperling-Bennet (RRSB) distribution and an average diameter of 35 {mu}m) and suspended in water. The leaching process was observed by repeated analysis of the suspension concerning pH, soluble sulfate and metals, and remaining S{sup 0}. In the case of abiotic leaching with H{sub 2}SO{sub 4}, the reaction between the acid and the sediment resulted in a gradual increase in pH and a solubilization of sediment-borne heavy metals which required some time; 80 % of the finally solubilized heavy metals was dissolved after 1 h, 90 % after 10 h, and 100 % after 100 h. In the case of bioleaching, the rate of S{sup 0} oxidation was maximal at the beginning, gradually diminished with time, and was proportional to the initial amount of S{sup 0}. Due to its very low solubility in water, S{sup 0} is oxidized in a surface reaction catalyzed by attached bacteria. The oxidation let the particles shrink, their surface became smaller and, thus, the S{sup 0} oxidation rate gradually decreased. The shrinking rate was time-invariant and, at 30 C, amounted to 0.5 {mu}m/day (or 100 {mu}g/cm{sup 2}/day). Within 21 days, 90 % of the applied S{sup 0} was oxidized. Three models with a different degree of complexity have been developed that describe this S{sup 0} oxidation, assuming S{sup 0} particles of uniform size (I), using a measured particle size distribution (II), or applying an adapted RRSB distribution (III

Effects of pollution and bioleaching process on the mineral composition and texture of contaminated sediments of the Reconquista River, Argentina.

Science.gov (United States)

Tufo, Ana E; Porzionato, Natalia F; Curutchet, Gustavo

2017-10-31

In this work, we report on the structural and textural changes in fluvial sediments from Reconquista River´s basin, Argentina, due to processes of contamination with organic matter and remediation by bioleaching. The original uncontaminated matrix showed quartz and phyllosilicates as the main primary mineral constituents and phases of interstratified illite-montmorillonite as secondary minerals. It was found that in contaminated sediments, the presence of organic matter in high concentration causes changes in the specific surface area, particle size distribution, size and distribution of micro and meso, and the morphology of the particles with respect to the uncontaminated sediment. After the bioleaching process, there were even greater changes in these parameters at the level of secondary mineral formation and the appearance of nanoparticles, which were confirmed by SEM. Especially, we found the formation of cementing substances such as gypsum, promoting the formation of macroporous aggregates and the weathering of clay components. Our results indicate that the bioleaching not only decreases the content of metals but also favors the formation of a material with improved characteristics for potential future applications.

Production of Synbiotic Yogurt-Like Using Indigenous Lactic Acid Bacteria as Functional Food

Directory of Open Access Journals (Sweden)

M. Astawan

2012-04-01

Full Text Available Yoghurt is a product of fermented milk using Lactobacillus bulgaricus and Streptococcus thermophilus as culture starter. Indigenous probiotic lactic acid bacteria, Lactobacillus plantarum 2C12 or Lactobacillus acidophilus 2B4, were applied in the making of functional synbiotic yoghurt-like with 5% of fructo-oligosaccharide (FOS as a prebiotic source. The aim of this study was to determine the best formula of functional synbiotic yoghurt-like among four formulas: F1 (L. bulgaricus + S. thermophilus, F2 (L. bulgaricus + S. thermophilus + L. plantarum 2C12, F3 (L. bulgaricus+ S. thermophilus + L. acidophilus 2B4, and F4 (L. bulgaricus + S. thermophilus + L. plantarum 2C12 + L. acidophilus 2B4 to be choosen and followed detection of it’s flavor to improve the product quality and consumer acceptance. The results showed that the F3 synbiotic yogurt made from mixed culture L. bulgaricus, S. thermophilus, and L. acidophilus 2B4 had the highest antibacterial effect against Enteropathogenic Escherichia coli (EPEC. Addition of 1.75% natural corn starch as a stabilizer produced optimum improvement in yoghurt consistency and minimize whey separation. Result of sensory evaluation indicated that the yoghurt with addition of 1% strawberry flavor and 0.1% vanilla flavor were ranked at first and second. Yoghurts were still good to be consumed after 15 d storage period at the refrigeration temperature (10 oC.

Characterization of bacteria acidophilic in samples of water coming into a region that suffers influence of uranium mine in Caldas (MG)

International Nuclear Information System (INIS)

Campos, Michelle B.; Ferrari, Carla R.; Roque, Claudio V.; Ronqui, Leilane B.; Nascimento, Marcos R.L. do; Rodgher, Suzelei; Azevedo, Heliana

2009-01-01

The fundamental condition for the bioleaching of the uranium ore is the presence of metallic sulfide such as pyrite associated with the ore, which is found in the ore and in the waste at the Unidade de Tratamento de Minerio (UTM) of Pocos de Caldas, State of Minas Gerais, Brazil. The present study aims to determine the chemical and microbiological characteristics in effluents of uranium mining from the UTM and in Antas dam, which receives treated effluents from the UTM. Water samples were collected Pit Mine (CM), located within the UTM facilities and from site 41 (Antas dam) in July and October 2008. We verified low pH values in water samples from CM (3.7) in comparison to the ones found at site 41 (6.65). There was a higher medium density value of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and heterotrophic acidophilic bacteria in water samples at site CM compared to the values recorded from samples at site 41. Medium values of Fe 2+ , uranium and zinc in samples from the site CM were higher than at site 41. The concentration of fluoride (68.5 mL -l ) and manganese (2.34 mL -1 ) in water samples from site 41 were above the limits fixed for water bodies in Resolution CONAMA 357. The relative seasonal variation of some variables observed at site CM (low pH values, high densities of Acidithiobacillus sp. and heterotrophic acidophilic bacteria) shows that this site is one of the main sites of occurrence of acid mine drainage and action of bioleaching bacteria at UTM. (author)

Comparative bioleaching of metals from pulverized and non-pulverized PCBs of cell phone charger: advantages of non-pulverized PCBs.

Science.gov (United States)

Joshi, Vyenkatesh; Shah, Neha; Wakte, Prashant; Dhakephalkar, Prashant; Dhakephalkar, Anita; Khobragade, Rahul; Naphade, Bhushan; Shaikh, Sajid; Deshmukh, Arvind; Adhapure, Nitin

2017-12-01

Sample inhomogeneity is a severe issue in printed circuit boards especially when we are comparing the bioleaching efficiency. To avoid the ambiguous results obtained due to inhomogeneity in PCBs, 12 similar cell phone chargers (of renowned company) having same make and batch number were collected from scrap market. PCBs obtained from them were used in present studies. Out of these 12, three PCBs were used separately for chemical analysis of PCBs with prior acid digestion in aqua regia. It was found that, 10.8, 68.0, and 710.9 mg/l of Zn, Pb, and Cu were present in it, respectively. Six PCBs were used for bioleaching experiment with two variations, pulverized and non-pulverized. Though the pulverized sample have shown better leaching than non-pulverized one, former has some disadvantages if overall recycling of e-waste (metallic and nonmetallic fraction) is to be addressed. At the end of leaching experiments, copper was recovered using a simple setup of electrodeposition and 92.85% recovery was attained. The acidophiles involved in bioleaching were identified by culture dependent and culture independent techniques such as DGGE and species specific primers in PCR.

Recovery of Cobalt as Cobalt Oxalate from Cobalt Tailings Using Moderately Thermophilic Bioleaching Technology and Selective Sequential Extraction

Directory of Open Access Journals (Sweden)

Guobao Chen

2016-07-01

Full Text Available Cobalt is a very important metal which is widely applied in various critical areas, however, it is difficult to recover cobalt from minerals since there is a lack of independent cobalt deposits in nature. This work is to provide a complete process to recover cobalt from cobalt tailings using the moderately thermophilic bioleaching technology and selective sequential extraction. It is found that 96.51% Co and 26.32% Cu were extracted after bioleaching for four days at 10% pulp density. The mean compositions of the leach solutions contain 0.98 g·L−1 of Co, 6.52 g·L−1 of Cu, and 24.57 g·L−1 of Fe (III. The copper ion was then recovered by a solvent extraction process and the ferric ions were selectively removed by applying a goethite deironization process. The technological conditions of the above purification procedures were deliberately discussed. Over 98.6% of copper and 99.9% of ferric ions were eliminated from the leaching liquor. Cobalt was finally produced as cobalt oxalate and its overall recovery during the whole process was greater than 95%. The present bioleaching process of cobalt is worth using for reference to deal with low-grade cobalt ores.

The analysis of the defense mechanism against indigenous bacterial translocation in X-irradiated mice

International Nuclear Information System (INIS)

Kobayashi, Toshiya; Ohmori, Toshihiro; Yanai, Minoru; Kawanishi, Gosei; Mitsuyama, Masao; Nomoto, Kikuo.

1991-01-01

The defense mechanism against indigenous bacterial translocation was studied using a model of endogenous infection in X-irradiated mice. All mice irradiated with 9 Gy died from day 8 to day 15 after irradiation. The death of mice was observed in parallel with the appearance of bacteria from day 7 in various organs, and the causative agent was identified to be Escherichia coli, an indigenous bacterium translocating from the intestine. Decrease in the number of blood leukocytes, peritoneal cells and lymphocytes in Peyer's patches or mesenteric lymph nodes was observed as early as 1 day after irradiation with 6 or 9 Gy. The mitogenic response of lymphocytes from various lymphoid tissues was severely affected as well. The impairment of these parameters for host defense reached the peak 3 days after irradiation and there was no recovery. However, in vivo bacterial activity of Kupffer cells in mice irradiated with 9 Gy was maintained in a normal level for a longer period. It was suggested that Kupffer cells play an important role in the defense against indigenous bacteria translocating from the intenstine in mice. (author)

Development of tailored indigenous marine consortia for the degradation of naturally weathered polyethylene films.

Science.gov (United States)

Syranidou, Evdokia; Karkanorachaki, Katerina; Amorotti, Filippo; Repouskou, Eftychia; Kroll, Kevin; Kolvenbach, Boris; Corvini, Philippe F-X; Fava, Fabio; Kalogerakis, Nicolas

2017-01-01

This study investigated the potential of bacterial-mediated polyethylene (PE) degradation in a two-phase microcosm experiment. During phase I, naturally weathered PE films were incubated for 6 months with the indigenous marine community alone as well as bioaugmented with strains able to grow in minimal medium with linear low-density polyethylene (LLDPE) as the sole carbon source. At the end of phase I the developed biofilm was harvested and re-inoculated with naturally weathered PE films. Bacteria from both treatments were able to establish an active population on the PE surfaces as the biofilm community developed in a time dependent way. Moreover, a convergence in the composition of these communities was observed towards an efficient PE degrading microbial network, comprising of indigenous species. In acclimated communities, genera affiliated with synthetic (PE) and natural (cellulose) polymer degraders as well as hydrocarbon degrading bacteria were enriched. The acclimated consortia (indigenous and bioaugmented) reduced more efficiently the weight of PE films in comparison to non-acclimated bacteria. The SEM images revealed a dense and compact biofilm layer and signs of bio-erosion on the surface of the films. Rheological results suggest that the polymers after microbial treatment had wider molecular mass distribution and a marginally smaller average molar mass suggesting biodegradation as opposed to abiotic degradation. Modifications on the surface chemistry were observed throughout phase II while the FTIR profiles of microbially treated films at month 6 were similar to the profiles of virgin PE. Taking into account the results, we can suggest that the tailored indigenous marine community represents an efficient consortium for degrading weathered PE plastics.

Development of tailored indigenous marine consortia for the degradation of naturally weathered polyethylene films.

Directory of Open Access Journals (Sweden)

Evdokia Syranidou

Full Text Available This study investigated the potential of bacterial-mediated polyethylene (PE degradation in a two-phase microcosm experiment. During phase I, naturally weathered PE films were incubated for 6 months with the indigenous marine community alone as well as bioaugmented with strains able to grow in minimal medium with linear low-density polyethylene (LLDPE as the sole carbon source. At the end of phase I the developed biofilm was harvested and re-inoculated with naturally weathered PE films. Bacteria from both treatments were able to establish an active population on the PE surfaces as the biofilm community developed in a time dependent way. Moreover, a convergence in the composition of these communities was observed towards an efficient PE degrading microbial network, comprising of indigenous species. In acclimated communities, genera affiliated with synthetic (PE and natural (cellulose polymer degraders as well as hydrocarbon degrading bacteria were enriched. The acclimated consortia (indigenous and bioaugmented reduced more efficiently the weight of PE films in comparison to non-acclimated bacteria. The SEM images revealed a dense and compact biofilm layer and signs of bio-erosion on the surface of the films. Rheological results suggest that the polymers after microbial treatment had wider molecular mass distribution and a marginally smaller average molar mass suggesting biodegradation as opposed to abiotic degradation. Modifications on the surface chemistry were observed throughout phase II while the FTIR profiles of microbially treated films at month 6 were similar to the profiles of virgin PE. Taking into account the results, we can suggest that the tailored indigenous marine community represents an efficient consortium for degrading weathered PE plastics.

Energy sources of yoghurt bacteria and enhancement of their ...

African Journals Online (AJOL)

Administrator

2011-05-23

May 23, 2011 ... starter culture consists of two symbiotically growing bacteria, S. thermophilus .... inoculated aseptically with pure colonies of the bacterial isolates. All ..... load and enzyme production of indigenously isolated yeast. Pak. J. Bot.

Evolution of copper arsenate resistance for enhanced enargite bioleaching using the extreme thermoacidophile Metallosphaera sedula.

Science.gov (United States)

Ai, Chenbing; McCarthy, Samuel; Liang, Yuting; Rudrappa, Deepak; Qiu, Guanzhou; Blum, Paul

2017-12-01

Adaptive laboratory evolution (ALE) was employed to isolate arsenate and copper cross-resistant strains, from the copper-resistant M. sedula CuR1. The evolved strains, M. sedula ARS50-1 and M. sedula ARS50-2, contained 12 and 13 additional mutations, respectively, relative to M. sedula CuR1. Bioleaching capacity of a defined consortium (consisting of a naturally occurring strain and a genetically engineered copper sensitive strain) was increased by introduction of M. sedula ARS50-2, with 5.31 and 26.29% more copper recovered from enargite at a pulp density (PD) of 1 and 3% (w/v), respectively. M. sedula ARS50-2 arose as the predominant species and modulated the proportions of the other two strains after it had been introduced. Collectively, the higher Cu 2+ resistance trait of M. sedula ARS50-2 resulted in a modulated microbial community structure, and consolidating enargite bioleaching especially at elevated PD.

The performance of leaching and bio-leaching from sulphide ores usiing SEVOP

OpenAIRE

Krstev, Boris; Krstev, Aleksandar; Golomeov, Blagoj; Golomeova, Mirjana; Sala, Ferat; Gocev, Zivko; Zivanovic, Jordan; Krstev, Dejan

2013-01-01

The refractory or low grade copper chalcopyrite ores or galena/sphalerite domestic ores in Republic of Macedonia are investigated by conventional copper flotation and selective flotation for galena/sphalerite. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer programme. Multisimple...

The principles and examples of leaching and bio-leaching using SImplex EVOP

OpenAIRE

Krstev, Aleksandar; Krstev, Boris

2014-01-01

The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms - bioleaching. The paper is result of these technologies and investigations earned out for recovery of in the mentioned ores. Using Simples EVOP and computer program Multisimplex performances are appropriate and most acceptable and excellen...

Oligotrophy and pelagic marine bacteria : Facts and fiction

NARCIS (Netherlands)

Schut, F; Prins, R.A; Gottschal, J.C

1997-01-01

Oligotrophy, or the inability of bacterial cells to propagate at elevated nutrient concentrations, is a controversial phenomenon in microbiology. The exact cause of the unculturability of many indigenous marine bacteria on standard laboratory media has still not been resolved. Unfortunately the

Effect of anaerobiosis on indigenous microorganisms in blackwater with fish offal as co-substrate

DEFF Research Database (Denmark)

Gunnarsdottir, Ragnhildur; Heiske, Stefan; Jensen, Pernille Erland

2014-01-01

resistant bacteria were reduced in the anaerobic samples in the beginning of the study but increased towards the end of it. The opposite pattern was observed in the aerobic samples, with a growth in the beginning followed by a reduction. During the anaerobic digestion tetracycline resistant bacteria showed......The aim of this study was to compare the effect of mesophilic anaerobic digestion with aerobic storage on the survival of selected indigenous microorganisms and microbial groups in blackwater, including the effect of addition of Greenlandic Halibut and shrimp offal. The methane yield...... of the different substrate mixtures was determined in batch experiments to study possible correlation between methanogenic activity in the anaerobic digesters and reduction of indigenous microorganisms in the blackwater. By the end of the experiments a recovery study was conducted to determine possible injury...

Bioleaching remediation of heavy metal-contaminated soils using Burkholderia sp. Z-90.

Science.gov (United States)

Yang, Zhihui; Zhang, Zhi; Chai, Liyuan; Wang, Yong; Liu, Yi; Xiao, Ruiyang

2016-01-15

Bioleaching is an environment-friendly and economical technology to remove heavy metals from contaminated soils. In this study, a biosurfactant-producing strain with capacity of alkaline production was isolated from cafeteria sewer sludge and its capability for removing Zn, Pb, Mn, Cd, Cu, and As was investigated. Phylogenetic analysis using 16S rDNA gene sequences confirmed that the strain belonged to Burkholderia sp. and named as Z-90. The biosurfactant was glycolipid confirmed by thin layer chromatography and Fourier-transform infrared spectroscopy. Z-90 broth was then used for bioleaching remediation of heavy metal-contaminated soils. The removal efficiency was 44.0% for Zn, 32.5% for Pb, 52.2% for Mn, 37.7% for Cd, 24.1% for Cu and 31.6% for As, respectively. Mn, Zn and Cd were more easily removed from soil than Cu, Pb and As, which was attributed to the presence of high acid-soluble fraction of Mn, Zn and Cd and high residual fraction of Cu, Pb and As. The heavy metal removal in soils was contributed to the adhesion of heavy metal-contaminated soil minerals with strain Z-90 and the formation of a metal complex with biosurfactant. Copyright © 2015 Elsevier B.V. All rights reserved.

Perspectives regarding the use of metallurgical slags as secondary metal resources - A review of bioleaching approaches.

Science.gov (United States)

Potysz, Anna; van Hullebusch, Eric D; Kierczak, Jakub

2018-05-05

Smelting activity by its very nature produces large amounts of metal-bearing waste, often called metallurgical slag(s). In the past, industry used to dispose of these waste products at dumping sites without the appropriate environmental oversight. Once there, ongoing biogeochemical processes affect the stability of the slags and cause the release of metallic contaminants. Rather than viewing metallurgical slags as waste, however, such deposits should be viewed as secondary metal resources. Metal bioleaching is a "green" treatment route for metallurgical slags, currently being studied under laboratory conditions. Metal-laden leachates obtained at the bioleaching stage have to be subjected to further recovery operations in order to obtain metal(s) of interest to achieve the highest levels of purity possible. This perspective paper considers the feasibility of the reuse of base-metal slags as secondary metal resources. Special focus is given to current laboratory bioleaching approaches and associated processing obstacles. Further directions of research for development of more efficient methods for waste slag treatment are also highlighted. The optimized procedure for slag treatment is defined as the result of this review and should include following steps: i) slag characterization (chemical and phase composition and buffering capacity) following the choice of initial pH, ii) the choice of particle size, iii) the choice of the liquid-to-solid ratio, iv) the choice of microorganisms, v) the choice of optimal nutrient supply (growth medium composition). An optimal combination of all these parameters will lead to efficient extraction and generation of metal-free solid residue. Copyright © 2018 Elsevier Ltd. All rights reserved.

Removal of trace metals and improvement of dredged sediment dewaterability by bioleaching combined with Fenton-like reaction.

Science.gov (United States)

Zeng, Xiangfeng; Twardowska, Irena; Wei, Shuhe; Sun, Lina; Wang, Jun; Zhu, Jianyu; Cai, Jianchao

2015-05-15

Bioleaching by Aspergillus niger strain SY1 combined with Fenton-like reaction was optimized to improve trace metal removal and dewaterability of dredged sediments. The major optimized parameters were the duration of bioleaching and H₂O₂ dose in Fenton-like process (5 days and 2g H₂O₂/L, respectively). Bioleaching resulted in the removal of ≈90% of Cd, ≈60% of Zn and Cu, ≈20% of Pb, and in decrease of sediment pH from 6.6 to 2.5 due to organic acids produced by A. niger. After addition of H₂O₂, Fenton-like reaction was initiated and further metal removal occurred. Overall efficiency of the combined process comprised: (i) reduction of Cd content in sediment by 99.5%, Cu and Zn by >70% and Pb by 39% as a result of metal release bound in all mobilizable fractions; (ii) decrease of sediment capillary suction time (CST) from 98.2s to 10.1s (by 89.8%) and specific resistance to filtration (SRF) from 37.4×10(12)m/kg to 6.2×10(12)m/kg (by 83.8%), due to reducing amount of extracellular polymeric substances (EPS) by 68.7% and bound water content by 79.1%. The combined process was found to be an efficient method to remove trace metals and improve dewaterability of contaminated dredged sediments. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of bacteria acidophilic in samples of water coming into a region that suffers influence of uranium mine in Caldas (MG)

Energy Technology Data Exchange (ETDEWEB)

Campos, Michelle B.; Ferrari, Carla R.; Roque, Claudio V.; Ronqui, Leilane B.; Nascimento, Marcos R.L. do; Rodgher, Suzelei; Azevedo, Heliana [Laboratorio de Pocos de Caldas (LAPOC-CNEN/MG), MG (Brazil)], e-mail: michelle_borato@hotmail.com, e-mail: carlarolimferrari@yahoo.com.br, e-mail: cvroque@cnen.gov.br, e-mail: leilanebio@yahoo.com.br, e-mail: pmarcos@cnen.gov.br, e-mail: surodgher@uol.com.br, e-mail: hgomes@cnen.gov.br

2009-07-01

The fundamental condition for the bioleaching of the uranium ore is the presence of metallic sulfide such as pyrite associated with the ore, which is found in the ore and in the waste at the Unidade de Tratamento de Minerio (UTM) of Pocos de Caldas, State of Minas Gerais, Brazil. The present study aims to determine the chemical and microbiological characteristics in effluents of uranium mining from the UTM and in Antas dam, which receives treated effluents from the UTM. Water samples were collected Pit Mine (CM), located within the UTM facilities and from site 41 (Antas dam) in July and October 2008. We verified low pH values in water samples from CM (3.7) in comparison to the ones found at site 41 (6.65). There was a higher medium density value of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and heterotrophic acidophilic bacteria in water samples at site CM compared to the values recorded from samples at site 41. Medium values of Fe{sup 2+}, uranium and zinc in samples from the site CM were higher than at site 41. The concentration of fluoride (68.5 mL{sup -l}) and manganese (2.34 mL{sup -1}) in water samples from site 41 were above the limits fixed for water bodies in Resolution CONAMA 357. The relative seasonal variation of some variables observed at site CM (low pH values, high densities of Acidithiobacillus sp. and heterotrophic acidophilic bacteria) shows that this site is one of the main sites of occurrence of acid mine drainage and action of bioleaching bacteria at UTM. (author)

Integrated bioleaching of copper metal from waste printed circuit board-a comprehensive review of approaches and challenges.

Science.gov (United States)

Awasthi, Abhishek Kumar; Zeng, Xianlai; Li, Jinhui

2016-11-01

Waste electrical and electronic equipment (e-waste) is the most rapidly growing waste stream in the world, and the majority of the residues are openly disposed of in developing countries. Waste printed circuit boards (WPCBs) make up the major portion of e-waste, and their informal recycling can cause environmental pollution and health risks. Furthermore, the conventional disposal and recycling techniques-mechanical treatments used to recover valuable metals, including copper-are not sustainable in the long term. Chemical leaching is rapid and efficient but causes secondary pollution. Bioleaching is a promising approach, eco-friendly and economically feasible, but it is slower process. This review considers the recycling potential of microbes and suggests an integrated bioleaching approach for Cu extraction and recovery from WPCBs. The proposed recycling system should be more effective, efficient and both technically and economically feasible.

Indigenous homelessness

DEFF Research Database (Denmark)

Being homeless in one’s homeland is a colonial legacy for many Indigenous people in settler societies. The construction of Commonwealth nation-states from colonial settler societies depended on the dispossession of Indigenous peoples from their lands. The legacy of that dispossession and related...... attempts at assimilation that disrupted Indigenous practices, languages, and cultures—including patterns of housing and land use—can be seen today in the disproportionate number of Indigenous people affected by homelessness in both rural and urban settings. Essays in this collection explore the meaning...... and scope of Indigenous homelessness in the Canada, Australia, and New Zealand. They argue that effective policy and support programs aimed at relieving Indigenous homelessness must be rooted in Indigenous conceptions of home, land, and kinship, and cannot ignore the context of systemic inequality...

Effects of moisture content on long-term survival and regrowth of bacteria in wastewater sludge

Energy Technology Data Exchange (ETDEWEB)

Yeager, J.G. (BDM Corp., Albuquerque, NM); Ward, R.L.

1981-05-01

The effects of moisture content on the survival and regrowth of seeded and indigenous enteric bacteria in raw sludge were determined. Cultures of six strains of fecally associated bacteria grown in sterilized, liquid sludge (5% solids) were all quite stable at this moisture level for over 90 days at 21/sup 0/C. When the moisture content of the sludge containing these organisms was reduced by evaporation and the samples were stored at 21/sup 0/C for extended periods, bacterial inactivation rates were generally proportional to the moisture losses of the samples. A dramatic reversal in this effect was observed in samples containing more than 90% solids. In this dried sludge, every bacterial species studied except Proteus mirabilis was found to be extremely stable. Bacteria indigenous to sludge were also found to survive for long periods in dried sludge. Growth of seeded Salmonella typhimurium was also found to occur in the presence of indigenous organisms in both liquid and dewatered raw sludges. However, the population density attained was well below that found in sterilized samples of the same sludges.

Bioleaching of Zn, Ni and Fe from contaminated sediments of water reservoir Ružín I with using heterotrophic bacterial strains

Directory of Open Access Journals (Sweden)

Katarína Jablonovská

2012-12-01

Full Text Available This study investigates the bioleaching of the zinc polluted sediment from water reservoir Ružín I using heterotrophic bacterialstrains ubiquitous in sediment environment. The effect of bacterial activity, pH, iron solubilization and precipitation and bioleachingmedium were evaluated. The pH value controls the bacterial activity during the leaching process. Addition of glucose to the bioleachingmedium accelerated the bioleaching rate. The results indicates, that the leachibility of zinc depend on the geochemical formsand surface interaction between metal and sediment fraction. Sequential chemical extraction confirm, that Zn was predominantly boundto the iron-manganese oxides.

Arsenate reduction and mobilization in the presence of indigenous aerobic bacteria obtained from high arsenic aquifers of the Hetao basin, Inner Mongolia

International Nuclear Information System (INIS)

Guo, Huaming; Liu, Zeyun; Ding, Susu; Hao, Chunbo; Xiu, Wei; Hou, Weiguo

2015-01-01

Intact aquifer sediments were collected to obtain As-resistant bacteria from the Hetao basin. Two strains of aerobic As-resistant bacteria (Pseudomonas sp. M17-1 and Bacillus sp. M17-15) were isolated from the aquifer sediments. Those strains exhibited high resistances to both As(III) and As(V). Results showed that both strains had arr and ars genes, and led to reduction of dissolved As(V), goethite-adsorbed As(V), scorodite As(V) and sediment As(V), in the presence of organic carbon as the carbon source. After reduction of solid As(V), As release was observed from the solids to solutions. Strain M17-15 had a higher ability than strain M17-1 in reducing As(V) and promoting the release of As. These results suggested that the strains would mediate As(V) reduction to As(III), and thereafter release As(III), due to the higher mobility of As(III) in most aquifer systems. The processes would play an important role in genesis of high As groundwater. - Highlights: • Two strains of As-resistant bacteria were isolated from high As aquifer sediment. • The strains (M17–1 and M17-15) had an As tolerance under oxic conditions. • The strains had arr and ars genes, and reduced both dissolved As(V) and solid As(V). • Reduction of solid As(V) resulted in As release into solutions. • M17-15 had a higher ability in reducing As(V) and promoting As release than M17-1. - Indigenous aerobic bacteria from the high-As aquifer sediment had arr and ars genes and led to reduction of dissolved As(V), goethite-adsorbed As(V), scorodite As(V) and sedimentary As

The Double Binds of Indigeneity and Indigenous Resistance

Directory of Open Access Journals (Sweden)

Francis Ludlow

2016-07-01

Full Text Available During the twentieth century, indigenous peoples have often embraced the category of indigenous while also having to face the ambiguities and limitations of this concept. Indigeneity, whether represented by indigenous people themselves or others, tends to face a “double bind”, as defined by Gregory Bateson, in which “no matter what a person does, he can’t win.” One exit strategy suggested by Bateson is meta-communication—communication about communication—in which new solutions emerge from a questioning of system-internal assumptions. We offer case studies from Ecuador, Peru and Alaska that chart some recent indigenous experiences and strategies for such scenarios.

Extraction, isolation and NMR data of the tetraether lipid calditoglycerocaldarchaeol (GDNT) from Sulfolobus metallicus harvested from a bioleaching reactor

CSIR Research Space (South Africa)

Bode, ML

2008-08-01

Full Text Available The successful extraction and isolation of the hydrolysed tetraether lipid calditoglycerocaldarchaeol (GDNT) from Sulfolobus etallicus, a key thermophilic bioleaching archaeon, is described. The archaeal biomasswas recovered directly from a...

The performance with data processing of chemical treatment with leaching and bio-leaching

OpenAIRE

Agron, Alili; Krstev, Boris; Krstev, Aleksandar; Stamenov, Goran

2015-01-01

The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and excel...

Stimulating Parenting Practices in Indigenous and Non-Indigenous Mexican Communities

Directory of Open Access Journals (Sweden)

Heather A. Knauer

2017-12-01

Full Text Available Parenting may be influenced by ethnicity; marginalization; education; and poverty. A critical but unexamined question is how these factors may interact to compromise or support parenting practices in ethnic minority communities. This analysis examined associations between mothers’ stimulating parenting practices and a range of child-level (age; sex; and cognitive and socio-emotional development; household-level (indigenous ethnicity; poverty; and parental education; and community-level (economic marginalization and majority indigenous population variables among 1893 children ages 4–18 months in poor; rural communities in Mexico. We also explored modifiers of associations between living in an indigenous community and parenting. Key findings were that stimulating parenting was negatively associated with living in an indigenous community or family self-identification as indigenous (β = −4.25; SE (Standard Error = 0.98; β = −1.58; SE = 0.83 respectively. However; living in an indigenous community was associated with significantly more stimulating parenting among indigenous families than living in a non-indigenous community (β = 2.96; SE = 1.25. Maternal education was positively associated with stimulating parenting only in indigenous communities; and household crowding was negatively associated with stimulating parenting only in non-indigenous communities. Mothers’ parenting practices were not associated with child sex; father’s residential status; education; or community marginalization. Our findings demonstrate that despite greater community marginalization; living in an indigenous community is protective for stimulating parenting practices of indigenous mothers.

Isolation of a strain of Acidithiobacillus caldus and its role in bioleaching of chalcopyrite

Energy Technology Data Exchange (ETDEWEB)

Zhou, Q.G.; Bo, F.; Bo, Z.H.; Xi, L.; Jian, G.; Fei, L.F.; Hua, C.X. [Central South University of Technology, Changsha (China)

2007-09-15

A moderately thermophilic and acidophilic sulfur-oxidizing bacterium named S-2, was isolated from coal heap drainage. The bacterium was motile, Gramnegative, rod-shaped, measured 0.4 to 0.6 by 1 to 2 gm, and grew optimally at 42-45{sup o}C and an initial pH of 2.5. The strain S-2 grew autotrophically by using elemental sulfur, sodium thiosulfate and potassium tetrathionate as energy sources. The strain did not use organic matter and inorganic minerals including ferrous sulfate, pyrite and chalcopyrite as energy sources. The morphological, biochemical, physiological characterization and analysis based on 16S rRNA gene sequence indicated that the strain S2 is most closely related to Acidithiobacillus caldus (> 99% similarity in gene sequence). The combination of the strain S-2 with Leptospirillum ferriphilum or Acidithiobacillus ferrooxidans in chalcopyrite bioleaching improved the copper-leaching efficiency. Scanning electron microscope (SEM) analysis revealed that the chalcopyrite surface in a mixed culture of Leptospirillum ferriphilum and Acidithiobacillus caldus was heavily etched. The energy dispersive X-ray (EDX) analysis indicated that Acidithiobacillus caldus has the potential role to enhance the recovery of copper from chalcopyrite by oxidizing the sulfur formed during the bioleaching progress.

The presentation of leaching and bio-leaching from different ores using SIMPLEX EVOP

OpenAIRE

Krstev, Boris; Krstev, Aleksandar; Golomeova, Mirjana; Gocev, Zivko

2013-01-01

The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

Isolasi dan Identifikasi Bakteri Asam Laktat Indigenous dari Sawi Asin

Directory of Open Access Journals (Sweden)

NiMade IndriHapsari Arihantana

2015-03-01

Full Text Available “Sawi asin” (fermented vegetable is a fermented product of vegetables which occur naturally (indigenous. Sawi asin has a longer shelf life then fresh or raw vegetables; due to a certain lactic acid bacteria (LAB presence in sawi asin which produces bacteriocin which destroy bacteria that causes food to spoil. The research was carried out to isolate and identify LAB species in sawi asin (sawi asin produced by MS, Malang; sawi asin produced by Niki Echo Surabaya and sawi asin produced by Wahana Boga Malang, East Java. The LAB characteristics such as cell morphology, Gram staining, motility, catalase, and gas production from glucose were observed.  Identification of LAB species was carried out by using kit equipment (sets API 50 CH and API 50 CHL medium version 5.1 continued by data analysis using APIWEB software. Result of research obtained were 21 LAB isolates (indigenous. The kit set used suceeded in identifying one LAB species, Lactobacillus fermentum 1 with five strains: L. fermentum I SAA1, L. fermentum I SAA2, L. fermentum I SAA4, L. fermentum I SAB1, and L. fermentum I SAC1.

Contributions of gut bacteria to Bacillus thuringiensis-induced mortality vary across a range of Lepidoptera

Directory of Open Access Journals (Sweden)

Holt Jonathan

2009-03-01

Full Text Available Abstract Background Gut microbiota contribute to the health of their hosts, and alterations in the composition of this microbiota can lead to disease. Previously, we demonstrated that indigenous gut bacteria were required for the insecticidal toxin of Bacillus thuringiensis to kill the gypsy moth, Lymantria dispar. B. thuringiensis and its associated insecticidal toxins are commonly used for the control of lepidopteran pests. A variety of factors associated with the insect host, B. thuringiensis strain, and environment affect the wide range of susceptibilities among Lepidoptera, but the interaction of gut bacteria with these factors is not understood. To assess the contribution of gut bacteria to B. thuringiensis susceptibility across a range of Lepidoptera we examined larval mortality of six species in the presence and absence of their indigenous gut bacteria. We then assessed the effect of feeding an enteric bacterium isolated from L. dispar on larval mortality following ingestion of B. thuringiensis toxin. Results Oral administration of antibiotics reduced larval mortality due to B. thuringiensis in five of six species tested. These included Vanessa cardui (L., Manduca sexta (L., Pieris rapae (L. and Heliothis virescens (F. treated with a formulation composed of B. thuringiensis cells and toxins (DiPel, and Lymantria dispar (L. treated with a cell-free formulation of B. thuringiensis toxin (MVPII. Antibiotics eliminated populations of gut bacteria below detectable levels in each of the insects, with the exception of H. virescens, which did not have detectable gut bacteria prior to treatment. Oral administration of the Gram-negative Enterobacter sp. NAB3, an indigenous gut resident of L. dispar, restored larval mortality in all four of the species in which antibiotics both reduced susceptibility to B. thuringiensis and eliminated gut bacteria, but not in H. virescens. In contrast, ingestion of B. thuringiensis toxin (MVPII following antibiotic

Indigenous Methodology in Understanding Indigenous Nurse Graduate Transition to Practice

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Donna L. M. Kurtz

2017-10-01

Full Text Available Increasing Indigenous health care professional presence in health care aims to reduce health inequities of Indigenous Peoples in Canada. Nurses are the largest health professional group and nurse graduates the main source of recruitment. The quality of graduate transition to practice is evident in the literature; however, little is reported about Indigenous new graduates. We describe using Indigenous methodology and two-eyed seeing (Indigenous and Western perspectives in exploring Indigenous transition experiences. Talking circles provided a safe environment for nurses, nurse educators and students, health managers, and policy makers to discuss Indigenous new graduate case scenarios. The methodology was critical in identifying challenges faced, recommendations for change, and a new collective commitment for cultural safety education, and ethical and respectful relationships within education, practice, and policy.

Screening and characterization of indigenous cellulolytic and xylanolytic bacteria

International Nuclear Information System (INIS)

Jong Bor Chyan; Pauline Liew Woan Ying; Mat Rasol Awang

2004-01-01

Ninety-six bacterial isolates were isolated from the soil samples collected from MADA Rice Experimental Plot, Kedah. Many of the isolates were Gram-positive bacteria suggesting this type of bacteria makes up the majority of the culturable populations residing in the plots investigated. These isolates were studied for their abilities to hydrolyse carboxymethyl cellulose (CMC) and xylan. Ability to hydrolyse CMC was observed in 61.5% of the isolates. Whilst 62.5% of the isolates exhibiting the ability to hydrolyse xylan. Active isolates were further confirmed by the presence of the respective gene(s) via molecular approaches. These isolates were later screened by restriction fragment length polymorphism (RFLP), and sequencing of representative 16S rDNAs. Majority of identified isolates were members of common soil microbe such as members of the genera Bacillus. (Author)

Effect of electrokinetic remediation on indigenous microbial activity and community within diesel contaminated soil.

Science.gov (United States)

Kim, Seong-Hye; Han, Hyo-Yeol; Lee, You-Jin; Kim, Chul Woong; Yang, Ji-Won

2010-07-15

Electrokinetic remediation has been successfully used to remove organic contaminants and heavy metals within soil. The electrokinetic process changes basic soil properties, but little is known about the impact of this remediation technology on indigenous soil microbial activities. This study reports on the effects of electrokinetic remediation on indigenous microbial activity and community within diesel contaminated soil. The main removal mechanism of diesel was electroosmosis and most of the bacteria were transported by electroosmosis. After 25 days of electrokinetic remediation (0.63 mA cm(-2)), soil pH developed from pH 3.5 near the anode to pH 10.8 near the cathode. The soil pH change by electrokinetics reduced microbial cell number and microbial diversity. Especially the number of culturable bacteria decreased significantly and only Bacillus and strains in Bacillales were found as culturable bacteria. The use of EDTA as an electrolyte seemed to have detrimental effects on the soil microbial activity, particularly in the soil near the cathode. On the other hand, the soil dehydrogenase activity was enhanced close to the anode and the analysis of microbial community structure showed the increase of several microbial populations after electrokinetics. It is thought that the main causes of changes in microbial activities were soil pH and direct electric current. The results described here suggest that the application of electrokinetics can be a promising soil remediation technology if soil parameters, electric current, and electrolyte are suitably controlled based on the understanding of interaction between electrokinetics, contaminants, and indigenous microbial community. Copyright 2010 Elsevier B.V. All rights reserved.

Gold biorecovery from e-waste: An improved strategy through spent medium leaching with pH modification.

Science.gov (United States)

Natarajan, Gayathri; Ting, Yen-Peng

2015-10-01

Rapid technological advancement and relatively short life time of electronic goods have resulted in an alarming growth rate of electronic waste which often contains significant quantities of toxic and precious metals. Compared to conventional recovery methods, bioleaching is an environmentally friendly process for metal extraction. Gold was bioleached from electronic scrap materials (ESM) via gold-cyanide complexation using cyanide produced from pure and mixed cultures of cyanogenic bacteria Chromobacterium violaceum, Pseudomonas aeruginosa and Pseudomonas fluorescens. As ESM was toxic to the bacteria, a two-step bioleaching approach was adopted where the solid waste was added to the bacterial culture after it has reached maximum growth and cyanide production during early stationary phase. Pure culture of C. violaceum showed the highest cyanide production, yielding maximum gold recovery of 11.3% at 0.5% w/v pulp density of ESM in two-step bioleaching. At the same pulp density of ESM, spent medium bioleaching using bacterial cell-free metabolites achieved gold recovery of 18%. Recovery increased to 30% when the pH of the spent medium was increased to shift the equilibrium in favor of cyanide ions production. It is demonstrated for the first time that pH modification of spent medium further improved metal solubilization and yielded higher metal recovery (compared to two-step bioleaching). Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioleaching of heavy metals from sewage sludge using Acidithiobacillus thiooxidans

Science.gov (United States)

Wen, Ye-Ming; Lin, Hong-Yan; Wang, Qing-Ping; Chen, Zu-Liang

2010-11-01

Acidithiobacillus thiooxidans was isolated from sewage sludge using the incubation in the Waksman liquor medium and the inoculation in Waksman solid plate. It was found that the optimum conditions of the bioleaching included solid concentration 2%, sulfur concentration 5 gṡL-1 and cell concentration 10%. The removal efficiency of Cr, Cu, Pb and Zh in sewage sludge, which was obtained from waste treatment plant, Jinshan, Fuzhou, was 43.65%, 96.24%, 41.61% and 96.50% in the period of 4˜10 days under the optimum conditions, respectively. After processing using the proposed techniques, the heavy metals in sewage sludge did meet the requirement the standards of nation.

Selective Recovery Of Copper From Solutions After Bioleaching Electronic Waste

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Willner Joanna

2015-06-01

Full Text Available Research on selective extraction of copper from solution after bioleaching grounded printed circuit boards (PCBs using LIX 860N-IC were conducted. The effect of LIX 860N-IC concentration, phase ratio and influence of initial pH value of aqueous phase on the extraction of copper and iron was examined. It was found that the extraction rate of copper increases with the LIX 860N-IC concentration. Best results of Cu extraction (98 % were achieved with extractant concentration of 5 % and pH 1.9. Higher pH value of aqueous phase (pH=2.4 is conducive to the simultaneous effect of Fe co-extraction.

Effect of dispersants on the growth of indigenous bacterial population and biodegradation of crude oil

Digital Repository Service at National Institute of Oceanography (India)

Bhosle, N.B.; Row, A.

Oil dispersants (5 from Castrol Ltd., Bombay and 2 from British Petroleum, London) were studied individually and in combination with Saudi Arabian crude oil for their effect on the growth of indigenous bacteria and on the biodegradation of oil. None...

Isolation of naphthalene-degrading bacteria from tropical marine sediments

International Nuclear Information System (INIS)

Zhuang, W.-Q.; Tay, J.-H.; Maszenan, A.M.; Tay, S.T.-L.

2003-01-01

Oil pollution is a major environmental concern in many countries, and this has led to a concerted effort in studying the feasibility of using oil-degrading bacteria for bioremediation. Although many oil-degrading bacteria have been isolated from different environments, environmental conditions can impose a selection pressure on the types of bacteria that can reside in a particular environment. This study reports the successful isolation of two indigenous naphthalene-degrading bacteria from oil-contaminated tropical marine sediments by enrichment culture. Strains MN-005 and MN-006 were characterized using an extensive range of biochemical tests. The 16S ribosomal deoxyribonucleic acid (rDNA) sequence analysis was also performed for the two strains. Their naphthalene degradation capabilities were determined using gas chromatography and DAPI counting of bacterial cells. Strains MN-005 and MN-006 are phenotypically and phylogenetically different from each other, and belong to the genera Staphylococcus and Micrococcus, respectively. Strains MN-005 and MN-006 has maximal specific growth rates (μ max ) of 0.082±0.008 and 0.30±0.02 per hour, respectively, and half-saturation constants (K s ) of 0.79±0.10 and 2.52±0.32 mg per litre, respectively. These physiological and growth studies are useful in assessing the potential of these indigenous isolates for in situ or ex situ naphthalene pollutant bioremediation in tropical marine environments. (author)

Biodegradation of crude oil by introduced psychotropic microbial association and indigenous bacteria under laboratory and field conditions in soils of Moscow region, Russia

Energy Technology Data Exchange (ETDEWEB)

Filonov, A.; Boronin, A. [Pushchino State Univ., Moscow (Russian Federation). Inst. of Biochemistry and Physiology of Microorganisms; Nechaeva, I.; Akhmetov, L.; Gafarov, A.; Puntus, I. [Pushchino State Univ., Moscow (Russian Federation)

2007-07-01

This paper presented an in-situ bioremediation method that accelerates the degradation of crude oil. Laboratory and field studies were conducted to determine the effect of adding mineral fertilizers such as nitrogen and phosphorus to stimulate the growth of microorganisms and accelerate microbial metabolism. The strongest effect was observed when nitrogen, phosphorous and potassium sources were added with microbial association jointly, particularly in field soil experiments. A 22 per cent oil spill removal was achieved due to metabolic activity of indigenous bacteria after only 2 months of experimenting. This study examined the kinetics of total number and crude oil degrading bacteria in the soil resulting from nutrient inoculation. It was shown that the rate of hydrocarbon degradation by microorganisms in the environment is determined by a range of factors such as temperature, soil pH, oxygen, water and nutritive availability. The use of psychotrophic degrader strains resulted in a higher degree of oil degradation in the field than in the laboratory. The study also revealed that the biodegradation process in polluted Arctic soils polluted with diesel was accelerated with the addition of degrader microorganisms. It was recommended that in cold climates, nitrogen, phosphorous and potassium should be introduced simultaneously. 21 refs., 1 tab., 4 figs.

Prediction of ferric iron precipitation in bioleaching process using partial least squares and artificial neural network

Directory of Open Access Journals (Sweden)

Golmohammadi Hassan

2013-01-01

Full Text Available A quantitative structure-property relationship (QSPR study based on partial least squares (PLS and artificial neural network (ANN was developed for the prediction of ferric iron precipitation in bioleaching process. The leaching temperature, initial pH, oxidation/reduction potential (ORP, ferrous concentration and particle size of ore were used as inputs to the network. The output of the model was ferric iron precipitation. The optimal condition of the neural network was obtained by adjusting various parameters by trial-and-error. After optimization and training of the network according to back-propagation algorithm, a 5-5-1 neural network was generated for prediction of ferric iron precipitation. The root mean square error for the neural network calculated ferric iron precipitation for training, prediction and validation set are 32.860, 40.739 and 35.890, respectively, which are smaller than those obtained by PLS model (180.972, 165.047 and 149.950, respectively. Results obtained reveal the reliability and good predictivity of neural network model for the prediction of ferric iron precipitation in bioleaching process.

Longitudinal nasopharyngeal carriage and antibiotic resistance of respiratory bacteria in indigenous Australian and Alaska native children with bronchiectasis.

Directory of Open Access Journals (Sweden)

Kim M Hare

Full Text Available BACKGROUND: Indigenous children in Australia and Alaska have very high rates of chronic suppurative lung disease (CSLD/bronchiectasis. Antibiotics, including frequent or long-term azithromycin in Australia and short-term beta-lactam therapy in both countries, are often prescribed to treat these patients. In the Bronchiectasis Observational Study we examined over several years the nasopharyngeal carriage and antibiotic resistance of respiratory bacteria in these two PCV7-vaccinated populations. METHODS: Indigenous children aged 0.5-8.9 years with CSLD/bronchiectasis from remote Australia (n = 79 and Alaska (n = 41 were enrolled in a prospective cohort study during 2004-8. At scheduled study visits until 2010 antibiotic use in the preceding 2-weeks was recorded and nasopharyngeal swabs collected for culture and antimicrobial susceptibility testing. Analysis of respiratory bacterial carriage and antibiotic resistance was by baseline and final swabs, and total swabs by year. RESULTS: Streptococcus pneumoniae carriage changed little over time. In contrast, carriage of Haemophilus influenzae declined and Staphylococcus aureus increased (from 0% in 2005-6 to 23% in 2010 in Alaskan children; these changes were associated with increasing age. Moraxella catarrhalis carriage declined significantly in Australian, but not Alaskan, children (from 64% in 2004-6 to 11% in 2010. While beta-lactam antibiotic use was similar in the two cohorts, Australian children received more azithromycin. Macrolide resistance was significantly higher in Australian compared to Alaskan children, while H. influenzae beta-lactam resistance was higher in Alaskan children. Azithromycin use coincided significantly with reduced carriage of S. pneumoniae, H. influenzae and M. catarrhalis, but increased carriage of S. aureus and macrolide-resistant strains of S. pneumoniae and S. aureus (proportion of carriers and all swabs, in a 'cumulative dose-response' relationship

Bioleaching of metals from WEEE shredding dust.

Science.gov (United States)

Marra, Alessandra; Cesaro, Alessandra; Rene, Eldon R; Belgiorno, Vincenzo; Lens, Piet N L

2018-03-15

A bioleaching process developed in two separate steps was investigated for the recovery of base metals, precious metals and rare earth elements from dusts generated by Waste Electrical and Electronic Equipment (WEEE) shredding. In the first step, base metals were almost completely leached from the dust in 8 days by Acidithiobacillus thiooxidans (DSM 9463) that lowered the pH of the leaching solution from 3.5 to 1.0. During this step, cerium, europium and neodymium were mobilized at high percentages (>99%), whereas lanthanum and yttrium reached an extraction yield of 80%. In the second step, the cyanide producing Pseudomonas putida WSC361 mobilized 48% of gold within 3 h from the A. thiooxidans leached shredding dust. This work demonstrated the potential application of biohydrometallurgy for resource recovery from WEEE shredding dust, destined to landfill disposal, and its effectiveness in the extraction of valuable substances, including elements at high supply risk as rare earths. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative assessment of metallurgical recovery of metals from electronic waste with special emphasis on bioleaching.

Science.gov (United States)

Priya, Anshu; Hait, Subrata

2017-03-01

Waste electrical and electronic equipment (WEEE) or electronic waste (e-waste) is one of the fastest growing waste streams in the urban environment worldwide. The core component of printed circuit board (PCB) in e-waste contains a complex array of metals in rich quantity, some of which are toxic to the environment and all of which are valuable resources. Therefore, the recycling of e-waste is an important aspect not only from the point of waste treatment but also from the recovery of metals for economic growth. Conventional approaches for recovery of metals from e-waste, viz. pyrometallurgical and hydrometallurgical techniques, are rapid and efficient, but cause secondary pollution and economically unviable. Limitations of the conventional techniques have led to a shift towards biometallurgical technique involving microbiological leaching of metals from e-waste in eco-friendly manner. However, optimization of certain biotic and abiotic factors such as microbial species, pH, temperature, nutrients, and aeration rate affect the bioleaching process and can lead to profitable recovery of metals from e-waste. The present review provides a comprehensive assessment on the metallurgical techniques for recovery of metals from e-waste with special emphasis on bioleaching process and the associated factors.

The Making of Indigeneity: a Study of Indigenous Representation in Peru

OpenAIRE

Gandrup, Tobias; Jespersgaard Jakobsen, Line

2013-01-01

This project is set out to analyse the negotiation of indigeneity. This will be done by unfolding the semiotic practices of two organisations that represents indigenous interests in contemporary Peruvian politics. It examines the rise of the term indigeneity in international politics through the emergence of an international framework and asks to how this has shaped political possibilities for the local indigenous organisations to represent the indigenous interests. The analysis shows that th...

Root-nodule bacteria isolated from native Amphithalea ericifolia and ...

African Journals Online (AJOL)

Indigenous root-nodule bacteria isolated from the acid sands of the Cape using Aspalathus linearis, Aspalathus hispida, Aspalathus carnosa, Aspalathus capensis and Amphithalea ericifolia as trap hosts showed considerable tolerance to low pH. Isolates from A. ericifolia and A. carnosa could even grow in YMB medium at ...

RARE OCCURRENCE OF HETEROTROPHIC BACTERIA WITH PATHOGENIC POTENTIAL IN POTABLE WATER

Science.gov (United States)

Since the discovery of Legionella pneumophila, an opportunistic pathogen that is indigenous to water, microbiologists have speculated that there may be other opportunistic pathogens among the numerous heterotrophic bacteria found in potable water. The USEPA developed a series of...

Co-culture microorganisms with different initial proportions reveal the mechanism of chalcopyrite bioleaching coupling with microbial community succession.

Science.gov (United States)

Ma, Liyuan; Wang, Xingjie; Feng, Xue; Liang, Yili; Xiao, Yunhua; Hao, Xiaodong; Yin, Huaqun; Liu, Hongwei; Liu, Xueduan

2017-01-01

The effect of co-culture microorganisms with different initial proportions on chalcopyrite bioleaching was investigated. Communities were rebuilt by six typical strains isolated from the same habitat. The results indicated, by community with more sulfur oxidizers at both 30 and 40°C, the final copper extraction rate was 19.8% and 6.5% higher, respectively, than that with more ferrous oxidizers. The variations of pH, redox potential, ferrous and copper ions in leachate also provided evidences that community with more sulfur oxidizers was more efficient. Community succession of free and attached cells revealed that initial proportions played decisive roles on community dynamics at 30°C, while communities shared similar structures, not relevant to initial proportions at 40°C. X-ray diffraction analysis confirmed different microbial functions on mineral surface. A mechanism model for chalcopyrite bioleaching was established coupling with community succession. This will provide theoretical basis for reconstructing an efficient community in industrial application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Using applicative software and software tools for the performance of leaching and bio-leaching

OpenAIRE

Krstev, Boris; Krstev, Aleksandar; Gocev, Zivko; Zdravev, Zoran; Krstev, Dejan; Zivanovic, Jordan

2013-01-01

The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

Effects of gamma-rays on an indigenous Bacillus isolate

International Nuclear Information System (INIS)

Jong Bor Chyan; Liew Pauline Woan Ying; Ahmad Zainuri Mohd Dzomir; Siti Khadijah Abu Hadin; Nabilahuda Mohd Tumirin

2010-01-01

A preliminary study was carried out with the aim to obtain strong cellulolytic bacteria by ionizing radiation using a 60 Co source. An indigenous cellulolytic Bacillus sp. NMBCC 10023 originally isolated from soil origin was used in the study. The harvested bacterial pellets from overnight growth cultures were exposed to gamma-irradiation with doses ranging from 1 kGy to 40 kGy. The numbers of surviving bacteria on agar plate decreased as the gamma irradiation dose increased. No isolates were recovered after exposure to doses greater than 10 kGy. Based on the cell count using plate count method, the 90 % lethal dose (LD90) of gamma radiation of Bacillus sp. NMBCC 10023 was between 2-4 kGy. (author)

Antagonistic activity of isolated lactic acid bacteria from Pliek U against gram-negative bacteria Escherichia coli ATCC 25922

Science.gov (United States)

Kiti, A. A.; Jamilah, I.; Rusmarilin, H.

2017-09-01

Lactic acid bacteria (LAB) is one group of microbes that has many benefits, notably in food and health industries sector. LAB plays an important role in food fermentation and it has bacteriostatic effect against the growth of pathogenic microorganisms. The research related LAB continued to be done to increase the diversity of potential isolates derived from nature which is indigenous bacteria for biotechnological purposes. This study was aimed to isolate and characterize LAB derived from pliek u sample and to examine the potency to inhibits Escherichia coli ATCC 25922 bacteria growth. A total of 5 isolates were isolated and based on morphological and physiological characteristics of the fifth bacteria, they are allegedly belonging to the genus Bacillus. Result of antagonistic test showed that the five isolates could inhibits the growth of E. coli ATCC 25922. The highest inhibition zone is 8.5 mm was shown by isolates NQ2, while the lowest inhibition is 1.5 mm was shown by isolates NQ3.

Motivation Matters: Profiling Indigenous and Non-Indigenous Students' Motivational Goals

Science.gov (United States)

Magson, Natasha R.; Craven, Rhonda G.; Nelson, Genevieve F.; Yeung, Alexander S.; Bodkin-Andrews, Gawaian H.; McInerney, Dennis M.

2014-01-01

This research explored gender and cross-cultural similarities and differences in the motivational profiles of Indigenous Papua New Guinean (PNG) and Indigenous and non-Indigenous Australians. Secondary students (N = 1,792) completed self-report motivational measures. Invariance testing demonstrated that the Inventory of School Motivation…

Effects of inoculation with organic-phosphorus-mineralizing bacteria on soybean (Glycine max) growth and indigenous bacterial community diversity.

Science.gov (United States)

Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Li, Yang; Duan, Man-Li

2017-05-01

Three different organic-phosphorus-mineralizing bacteria (OPMB) strains were inoculated to soil planted with soybean (Glycine max), and their effects on soybean growth and indigenous bacterial community diversity were investigated. Inoculation with Pseudomonas fluorescens Z4-1 and Brevibacillus agri L7-1 increased organic phosphorus degradation by 22% and 30%, respectively, compared with the control at the mature stage. Strains P. fluorescens Z4-1 and B. agri L7-1 significantly improved the soil alkaline phosphatase activity, average well color development, and the soybean root activity. Terminal restriction fragment length polymorphism analysis demonstrated that P. fluorescens Z4-1 and B. agri L7-1 could persist in the soil at relative abundances of 2.0%-6.4% throughout soybean growth. Thus, P. fluorescens Z4-1 and B. agri L7-1 could potentially be used in organic-phosphorus-mineralizing biofertilizers. OPMB inoculation altered the genetic structure of the soil bacterial communities but had no apparent influence on the carbon source utilization profiles of the soil bacterial communities. Principal components analysis showed that the changes in the carbon source utilization profiles of bacterial community depended mainly on the plant growth stages rather than inoculation with OPMB. The results help to understand the evolution of the soil bacterial community after OPMB inoculation.

Genetic Diversity and Symbiotic Efficiency of Indigenous Common Bean Rhizobia in Croatia

Directory of Open Access Journals (Sweden)

Ines Pohajda

2016-01-01

Full Text Available Nodule bacteria (rhizobia in symbiotic associations with legumes enable considerable entries of biologically fixed nitrogen into soil. Efforts are therefore made to intensify the natural process of symbiotic nitrogen fixation by legume inoculation. Studies of field populationsof rhizobia open up the possibility to preserve and probably exploit some indigenous strains with hidden symbiotic or ecological potentials. The main aim of the present study is to determine genetic diversity of common bean rhizobia isolated from different field sites in central Croatia and to evaluate their symbiotic efficiency and compatibility with host plants. The isolation procedure revealed that most soil samples contained no indigenous common bean rhizobia. The results indicate that the cropping history had a significant impact on the presence of indigenous strains. Although all isolates were found to belong to species Rhizobium leguminosarum, significant genetic diversity at the strain level was determined. Application of both random amplifi cation of polymorphic DNA (RAPD and enterobacterial repetitive intergenic consensus–polymerase chain reaction (ERIC-PCR methods resulted in similar grouping of strains. Symbiotic efficiency of indigenous rhizobia as well as their compatibility with two commonly grown bean varieties were tested in field experiments. Application of indigenous rhizobial strains as inoculants resulted in significantly different values of nodulation, seed yield as well as plant nitrogen and seed protein contents. The most abundant nodulation and the highest plant nitrogen and protein contents were determined in plants inoculated with R. leguminosarum strains S17/2 and S21/6. Although, in general, the inoculation had a positive impact on seed yield, differences depending on the applied strain were not determined. The overall results show the high degree of symbiotic efficiency of the specific indigenous strain S21/6. These results indicate different

Genetic Diversity and Symbiotic Efficiency of Indigenous Common Bean Rhizobia in Croatia.

Science.gov (United States)

Pohajda, Ines; Babić, Katarina Huić; Rajnović, Ivana; Kajić, Sanja; Sikora, Sanja

2016-12-01

Nodule bacteria (rhizobia) in symbiotic associations with legumes enable considerable entries of biologically fixed nitrogen into soil. Efforts are therefore made to intensify the natural process of symbiotic nitrogen fixation by legume inoculation. Studies of field populations of rhizobia open up the possibility to preserve and probably exploit some indigenous strains with hidden symbiotic or ecological potentials. The main aim of the present study is to determine genetic diversity of common bean rhizobia isolated from different field sites in central Croatia and to evaluate their symbiotic efficiency and compatibility with host plants. The isolation procedure revealed that most soil samples contained no indigenous common bean rhizobia. The results indicate that the cropping history had a significant impact on the presence of indigenous strains. Although all isolates were found to belong to species Rhizobium leguminosarum , significant genetic diversity at the strain level was determined. Application of both random amplification of polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC- -PCR) methods resulted in similar grouping of strains. Symbiotic efficiency of indigenous rhizobia as well as their compatibility with two commonly grown bean varieties were tested in field experiments. Application of indigenous rhizobial strains as inoculants resulted in significantly different values of nodulation, seed yield as well as plant nitrogen and seed protein contents. The most abundant nodulation and the highest plant nitrogen and protein contents were determined in plants inoculated with R. leguminosarum strains S 17/2 and S 21/6 . Although, in general, the inoculation had a positive impact on seed yield, differences depending on the applied strain were not determined. The overall results show the high degree of symbiotic efficiency of the specific indigenous strain S 21/6 . These results indicate different symbiotic

Inhibition of aflatoxin-producing aspergilli by lactic acid bacteria ...

African Journals Online (AJOL)

A total of six lactic acid bacteria (LAB) isolates were selected from five indigenously fermented cereal gruels and identified as Lactobacillus fermentum OYB, Lb. fermentum RS2, Lb. plantarum MW, Lb. plantarum YO, Lb. brevis WS3, and Lactococcus spp. RS3. Six aflatoxin-producing aspergilli were also selected from the ...

Urinary angiotensinogen excretion in Australian Indigenous and non-Indigenous pregnant women.

Science.gov (United States)

Pringle, Kirsty G; de Meaultsart, Celine Corbisier; Sykes, Shane D; Weatherall, Loretta J; Keogh, Lyniece; Clausen, Don C; Dekker, Gus A; Smith, Roger; Roberts, Claire T; Rae, Kym M; Lumbers, Eugenie R

2018-04-11

The intrarenal renin-angiotensin system (iRAS) is implicated in the pathogenesis of hypertension, chronic kidney disease and diabetic nephropathy. Urinary angiotensinogen (uAGT) levels reflect the activity of the iRAS and are altered in women with preeclampsia. Since Indigenous Australians suffer high rates and early onset of renal disease, we hypothesised that Indigenous Australian pregnant women, like non-Indigenous women with pregnancy complications, would have altered uAGT levels. The excretion of RAS proteins was measured in non-Indigenous and Indigenous Australian women with uncomplicated or complicated pregnancies (preeclampsia, diabetes/gestational diabetes, proteinuria/albuminuria, hypertension, small/large for gestational age, preterm birth), and in non-pregnant non-Indigenous women. Non-Indigenous pregnant women with uncomplicated pregnancies, had higher uAGT/creatinine levels than non-Indigenous non-pregnant women (P pregnant women with pregnancy complications, uAGT/creatinine was suppressed in the third trimester (P pregnant women with uncomplicated pregnancies, there was no change in uAGT/creatinine with gestational age and uAGT/creatinine was lower in the 2nd and 3rd trimesters than in non-Indigenous pregnant women with uncomplicated pregnancies (P pregnant women may reflect subclinical renal dysfunction which limits the ability of the kidney to maintain sodium balance and could indicate an increased risk of pregnancy complications and/or future renal disease. Copyright © 2018. Published by Elsevier B.V.

[Eating characteristics of Chilean indigenous and non-indigenous adolescent girls].

Science.gov (United States)

Araneda, Jacqueline; Amigo, Hugo; Bustos, Patricia

2010-03-01

During childhood and adolescence, eating habits become established which are instrumental in determining eating behavior later in life. Various authors have described the acculturation of the Mapuche people toward Western culture. The objective of this study was to analyze the eating characteristics of indigenous and non-indigenous adolescent girls in the Araucania Region of Chile. A cross-sectional design was used with a probabilistic sample of 281 adolescents comprised of 139 indigenous and 142 non-indigenous girls attending 168 elementary schools. A modified food frequency questionnaire was applied, designed to obtain information about eating habits and consumption of Mapuche foods. The eating schedules are similar in both ethnic groups, with dinner being the meal that is least consumed. Total snack consumption per week has a mean of 7 with an interquartile range (IQR) of 5 to 10 without any differences between ethnic groups; of these snacks, only 2 were healthy (IQR = 1 to 3). The indigenous girls had a higher probability of consumption of native foods including mote (boiled wheat) (OR = 2.00; IC = 0.93-4.29), muday (fermented cereal alcohol) (OR = 3.45; IC = 1.90-6.27), and yuyo (field mustard) (OR = 4.40; IC = 2.06-9.39). The study's conclusion is that the the eating habits and behavior of indigenous adolescents are similar to those of non-indigenous girls, though the former still consume more indigenous foods.

The complicated substrates enhance the microbial diversity and zinc leaching efficiency in sphalerite bioleaching system.

Science.gov (United States)

Xiao, Yunhua; Xu, YongDong; Dong, Weiling; Liang, Yili; Fan, Fenliang; Zhang, Xiaoxia; Zhang, Xian; Niu, Jiaojiao; Ma, Liyuan; She, Siyuan; He, Zhili; Liu, Xueduan; Yin, Huaqun

2015-12-01

This study used an artificial enrichment microbial consortium to examine the effects of different substrate conditions on microbial diversity, composition, and function (e.g., zinc leaching efficiency) through adding pyrite (SP group), chalcopyrite (SC group), or both (SPC group) in sphalerite bioleaching systems. 16S rRNA gene sequencing analysis showed that microbial community structures and compositions dramatically changed with additions of pyrite or chalcopyrite during the sphalerite bioleaching process. Shannon diversity index showed a significantly increase in the SP (1.460), SC (1.476), and SPC (1.341) groups compared with control (sphalerite group, 0.624) on day 30, meanwhile, zinc leaching efficiencies were enhanced by about 13.4, 2.9, and 13.2%, respectively. Also, additions of pyrite or chalcopyrite could increase electric potential (ORP) and the concentrations of Fe3+ and H+, which were the main factors shaping microbial community structures by Mantel test analysis. Linear regression analysis showed that ORP, Fe3+ concentration, and pH were significantly correlated to zinc leaching efficiency and microbial diversity. In addition, we found that leaching efficiency showed a positive and significant relationship with microbial diversity. In conclusion, our results showed that the complicated substrates could significantly enhance microbial diversity and activity of function.

Acquisition of useful and high ability genes for acidophilic bacteria; Kosansei saikin ni takai noryoku wo fuyosuru idenshi no kakutoku

Energy Technology Data Exchange (ETDEWEB)

Senda, T; Inoue, C; Shinbori, Y [Tohoku University, Sendai (Japan)

1997-02-01

This effort aims at the development of high-performance bacteria usable in bio-leaching in metal smelting by acquiring genes capable of realizing such. A method is used of choosing some isolated strains exhibiting high-performance traits and acquiring target genes therefrom by use of genetic engineering. Approximately 200 kinds in the aggregate of acidophilic bacteria are currently available for the study, including isolated iron-oxidizing and sulfur-oxidizing bacteria, standard species acquired for the study, and strains previously isolated by the laboratory. The bacteria are tested with respect to their Fe{sup 2+}-oxidizing rates, sulfur-oxidizing capabilities, and strength to withstand inhibiting substances (Ag{sup +}, Cl{sup -}, Mo{sup 6+}, etc.), which results in the nomination of 8 strains. The study planned to follow includes processes involving the extraction of chromosome DNAs from the 8 strains and their refinement, gene cloning by the Southern hybridization method, determination of their base sequences, determination of the difference between the strains in point of gene expression, and investigations of the relations that the results of these processes bear toward the said high-performance traits. Also under way is a study about the infuence-exerting factors revealed during the evaluation of the abilities of acidphlic bacteria. 2 refs., 2 tabs.

Fe extraction from çayeli copper ores by bioleaching with eco freiendly acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Kocadagistan, M.E.; Bayhan, Y.K.

2017-01-01

Recently, biological treatment; an important recovery process, has became important from the environmental and economical respects in recovery of metallic values from low-grade sulfur-bearing ores or concentrates. Bacterial ore leaching can be applied to extract heavy metals from low grade ores, industrial wastes and other materials on an industrial scale by different procedures. The main objective of this work was to investigate the dissolution of Fe from Çayeli copper ores, via a bioleaching process using Acidithiobacillus ferrooxidans. Experiments performed with batch operation in jar test equipment were conducted at different pH values, pulp densities, inoculum volumes, particle sizes, stirring conditions and operation times. The optimal parameters were found as follows; at pH 2, the pulp density; 4% (w/v), inoculum volume; 4% (v/v), stirring rate; 120 rpm and particle size; -0.053 mm for 192nd and 288th hours, at pH 2, the pulp density; 4% (w/v), inoculum volume; 5% (v/v), stirring speed; 200 rpm and particle size; -0.053 mm for 384th and 480th hours. By performing the bioleaching process under these conditions, almost 99% of the iron extent in the ore was transfer from ore into solution, however the experiments in which distilled water was used instead of modified 9K*, only 18.5% Fe efficiency was obtained. (author)

AKTIVITAS ANTIKAPANG BAKTERI ASAM LAKTAT TERHADAP PERTUMBUHAN KAPANG KONTAMINAN KEJI [Antimycotic Activity of Lactic Acid Bacteria on the Growth of Cheese Contaminating Molds

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S. Styahadi3

2006-04-01

Full Text Available Local cheese is frequently contaminated by toxigenic molds which is harmful for human health. Lactic acid bacteria have been proven to inhibit the growth of toxigenic mold in some food products. The research was aimed to study the activity of indigenous lactic acid bacteria to inhibit the growth of toxigenic molds in local cheese. The molds studied were isolated from local cheese production (Gouda type. The cheese contaminating molds were identified as Penicillium sp. and Aspergillus sp. Nine species of indigenous lactic acid bacteria (LAB were tested for antimycotic activities, i.e. Lactobacillus plantarum kik, Lactobacillus plantarum sa, Lactobacillus plantarum pi28a, Lactobacillus plantarum dd, Lactobacillus coryneformis, Lactobacillus brevis, Lactococcus piscium, Leuconostoc mesenteroides, and Leuconostoc paramesenteroides. The research revealed that the promising indigenous LAB which inhibited the contaminating molds was Lb plantarum pi28a. Application of Lb plantarum pi28a on local cheese production could inhibit the growth of Penicillium sp. and Aspergillus sp. up to 12 days.

Bioremediation of copper-contaminated soils by bacteria.

Science.gov (United States)

Cornu, Jean-Yves; Huguenot, David; Jézéquel, Karine; Lollier, Marc; Lebeau, Thierry

2017-02-01

Although copper (Cu) is an essential micronutrient for all living organisms, it can be toxic at low concentrations. Its beneficial effects are therefore only observed for a narrow range of concentrations. Anthropogenic activities such as fungicide spraying and mining have resulted in the Cu contamination of environmental compartments (soil, water and sediment) at levels sometimes exceeding the toxicity threshold. This review focuses on the bioremediation of copper-contaminated soils. The mechanisms by which microorganisms, and in particular bacteria, can mobilize or immobilize Cu in soils are described and the corresponding bioremediation strategies-of varying levels of maturity-are addressed: (i) bioleaching as a process for the ex situ recovery of Cu from Cu-bearing solids, (ii) bioimmobilization to limit the in situ leaching of Cu into groundwater and (iii) bioaugmentation-assisted phytoextraction as an innovative process for in situ enhancement of Cu removal from soil. For each application, the specific conditions required to achieve the desired effect and the practical methods for control of the microbial processes were specified.

Indigeneity: global and local.

Science.gov (United States)

Merlan, Francesca

2009-06-01

The term indigenous, long used to distinguish between those who are "native" and their "others" in specific locales, has also become a term for a geocultural category, presupposing a world collectivity of "indigenous peoples" in contrast to their various "others." Many observers have noted that the stimuli for internationalization of the indigenous category originated principally from particular nation-states-Anglo-American settler colonies and Scandinavia. All, I argue, are relevantly political cultures of liberal democracy and weighty (in different ways) in international institutional affairs. However, international indigeneity has not been supported in any unqualified way by actions taken in the name of several nation-states that were among its main points of origin. In fact, staunch resistance to the international indigenous project has recently come from four of them. In 2007, the only four voting countries to reject the main product of international indigenist activity over the past 30 years, the Declaration on the Rights of Indigenous Peoples, were Australia, the United States, Canada, and New Zealand. In these locations, forms of "indigenous relationship" emerged that launched international indigeneity and that strongly influenced international perceptions of what "indigeneity" is and who "indigenous peoples" may be. Some other countries say the model of indigenous relationship that they see represented by the "establishing" set is inapplicable to themselves (but have nonetheless had to take notice of expanding internationalist indigenism). The apparently paradoxical rejection of the draft declaration by the establishing countries is consistent with the combination of enabling and constraining forces that liberal democratic political cultures offer.

Adaptations of indigenous bacteria to fuel contamination in karst aquifers in south-central Kentucky

Science.gov (United States)

Byl, Thomas D.; Metge, David W.; Agymang, Daniel T.; Bradley, Michael W.; Hileman, Gregg; Harvey, Ronald W.

2014-01-01

The karst aquifer systems in southern Kentucky can be dynamic and quick to change. Microorganisms that live in these unpredictable aquifers are constantly faced with environmental changes. Their survival depends upon adaptations to changes in water chemistry, taking advantage of positive stimuli and avoiding negative environmental conditions. The U.S. Geological Survey conducted a study in 2001 to determine the capability of bacteria to adapt in two distinct regions of water quality in a karst aquifer, an area of clean, oxygenated groundwater and an area where the groundwater was oxygen depleted and contaminated by jet fuel. Water samples containing bacteria were collected from one clean well and two jet fuel contaminated wells in a conduit-dominated karst aquifer. Bacterial concentrations, enumerated through direct count, ranged from 500,000 to 2.7 million bacteria per mL in the clean portion of the aquifer, and 200,000 to 3.2 million bacteria per mL in the contaminated portion of the aquifer over a twelve month period. Bacteria from the clean well ranged in size from 0.2 to 2.5 mm, whereas bacteria from one fuel-contaminated well were generally larger, ranging in size from 0.2 to 3.9 mm. Also, bacteria collected from the clean well had a higher density and, consequently, were more inclined to sink than bacteria collected from contaminated wells. Bacteria collected from the clean portion of the karst aquifer were predominantly (,95%) Gram-negative and more likely to have flagella present than bacteria collected from the contaminated wells, which included a substantial fraction (,30%) of Gram-positive varieties. The ability of the bacteria from the clean portion of the karst aquifer to biodegrade benzene and toluene was studied under aerobic and anaerobic conditions in laboratory microcosms. The rate of fuel biodegradation in laboratory studies was approximately 50 times faster under aerobic conditions as compared to anaerobic, sulfur-reducing conditions. The

Taurocholate Deconjugation and Cholesterol Binding by Indigenous Dadih Lactic Acid Bacteria

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USMAN PATO

2005-09-01

Full Text Available High serum cholesterol levels have been associated with an increased risk for human coronary heart disease. Lowering of serum cholesterol has been suggested to prevent the heart disease. To reduce serum cholesterol levels one may consumed diet supplementat of fermented dairy product such as dadih. Lactic acid bacteria present in dadih may alter serum cholesterol by directly bind to dietary cholesterol and/or deconjugation of bile salts. Acid and bile tolerance, deconjugation of sodium taurocholate, and the cholesterol-binding ability of lactic acid bacteria from dadih were examined. Among ten dadih lactic acid bacteria tested, six strains namely I-11, I-2775, K-5, I-6257, IS-7257, and B-4 could bind cholesterol and deconjugate sodium taurocholate. However, the last four strains were very sensitive to bile. Therefore, Lactobacillus fermentum I-11 and Leuconostoc lactis subsp. lactis I-2775 those were tolerant to acid and oxgall (bile and deconjugated sodium taurocholate and bound cholesterol could be recommended as probiotic to prevent coronary heart disease.

Biodegradation of crude oil by introduced psychotropic microbial association and indigenous bacteria under laboratory and field conditions in soils of Moscow region, Russia. Volume 1

International Nuclear Information System (INIS)

Filonov, A.; Boronin, A.

2007-01-01

This paper presented an in-situ bioremediation method that accelerates the degradation of crude oil. Laboratory and field studies were conducted to determine the effect of adding mineral fertilizers such as nitrogen and phosphorus to stimulate the growth of microorganisms and accelerate microbial metabolism. The strongest effect was observed when nitrogen, phosphorous and potassium sources were added with microbial association jointly, particularly in field soil experiments. A 22 per cent oil spill removal was achieved due to metabolic activity of indigenous bacteria after only 2 months of experimenting. This study examined the kinetics of total number and crude oil degrading bacteria in the soil resulting from nutrient inoculation. It was shown that the rate of hydrocarbon degradation by microorganisms in the environment is determined by a range of factors such as temperature, soil pH, oxygen, water and nutritive availability. The use of psychotrophic degrader strains resulted in a higher degree of oil degradation in the field than in the laboratory. The study also revealed that the biodegradation process in polluted Arctic soils polluted with diesel was accelerated with the addition of degrader microorganisms. It was recommended that in cold climates, nitrogen, phosphorous and potassium should be introduced simultaneously. 21 refs., 1 tab., 4 figs

Biodegradation of crude oil by introduced psychotropic microbial association and indigenous bacteria under laboratory and field conditions in soils of Moscow region, Russia. Volume 1

Energy Technology Data Exchange (ETDEWEB)

Filonov, A.; Boronin, A. [Pushchino State Univ., Moscow (Russian Federation). Inst. of Biochemistry and Physiology of Microorganisms; Nechaeva, I.; Akhmetov, L.; Gafarov, A.; Puntus, I. [Pushchino State Univ., Moscow (Russian Federation)

2007-07-01

This paper presented an in-situ bioremediation method that accelerates the degradation of crude oil. Laboratory and field studies were conducted to determine the effect of adding mineral fertilizers such as nitrogen and phosphorus to stimulate the growth of microorganisms and accelerate microbial metabolism. The strongest effect was observed when nitrogen, phosphorous and potassium sources were added with microbial association jointly, particularly in field soil experiments. A 22 per cent oil spill removal was achieved due to metabolic activity of indigenous bacteria after only 2 months of experimenting. This study examined the kinetics of total number and crude oil degrading bacteria in the soil resulting from nutrient inoculation. It was shown that the rate of hydrocarbon degradation by microorganisms in the environment is determined by a range of factors such as temperature, soil pH, oxygen, water and nutritive availability. The use of psychotrophic degrader strains resulted in a higher degree of oil degradation in the field than in the laboratory. The study also revealed that the biodegradation process in polluted Arctic soils polluted with diesel was accelerated with the addition of degrader microorganisms. It was recommended that in cold climates, nitrogen, phosphorous and potassium should be introduced simultaneously. 21 refs., 1 tab., 4 figs.

Gold recovery from printed wiring board using bioleaching

Energy Technology Data Exchange (ETDEWEB)

Kita, Y. [Faculty of Engineering, Osaka Univ. (Japan); Nishikawa, H. [Center for Advanced Science and Innovation, Osaka Univ. (Japan); Takemoto, T. [Joining and Welding Research Inst., Osaka Univ. (Japan)

2004-07-01

In the electronic assembly, gold is frequently used as surface plating and a bonding wire. To recover gold from waste electronics, the dissolution process using cyan is a popular method, however, the solution is highly toxic. Accordingly, the environmentally conscious substitute process is preferable. In this study the possibility of Au dissolution from printed wiring boards using bioleaching has been investigated. Chromobacterium violaceum having ability of cyanide formation was used to dissolve Au. The printed wiring boards with gold plating of 0.07nm in thickness were immersed in synthetic medium with C. violaceum. After immersion test for 480h, the gold plating was completely dissolved. The increase in cyanide concentration gave little effect on the enhancement of dissolution of gold, however, the dissolution rate of Au was increased with increasing of dissolved oxygen in the medium. Chromobacterium violaceum produced 0.8mmol/l cyanide but it also decomposed about 60% of cyanide generated, therefore, this dissolution process could be used as an environmentally conscious method. (orig.)

Effect of Ferric Ions on Bioleaching of Pentlandite Concentrate

Science.gov (United States)

Li, Qian; Lai, Huimin; Yang, Yongbin; Xu, Bin; Jiang, Tao; Zhang, Yaping

The intensified effects of ferric phosphate and ferric sulfate as nutrient and oxidant on the bioleaching of pentlandite concentrate with Acidithiobacillus ferrooxidans and Sulfobacillus thermosulfidooxidans were studied. The results showed that the nickel leaching rate was enhanced continuously with FePO4 or Fe2(SO4)3 added in certain extent, but declined at excess. For A. ferrooxidans, the optimum additive amount of Fe2(SO4)3 was 6.63mM/L and the nickel leaching rate reached 71.76%. Compared with Fe2(SO4)3, the optimum additive amount of FePO4 was 26.52mM/L for both strains. For A. ferrooxidans and S. thermosulfidooxidans, the nickel leaching rate could increase to 98.06% and 98.11% which was 1.83 times and 1.55 times of the leachig rate of blank test, respectively.

Bioinformatic Prediction of Gene Functions Regulated by Quorum Sensing in the Bioleaching Bacterium Acidithiobacillus ferrooxidans

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Alvaro Banderas

2013-08-01

Full Text Available The biomining bacterium Acidithiobacillus ferrooxidans oxidizes sulfide ores and promotes metal solubilization. The efficiency of this process depends on the attachment of cells to surfaces, a process regulated by quorum sensing (QS cell-to-cell signalling in many Gram-negative bacteria. At. ferrooxidans has a functional QS system and the presence of AHLs enhances its attachment to pyrite. However, direct targets of the QS transcription factor AfeR remain unknown. In this study, a bioinformatic approach was used to infer possible AfeR direct targets based on the particular palindromic features of the AfeR binding site. A set of Hidden Markov Models designed to maintain palindromic regions and vary non-palindromic regions was used to screen for putative binding sites. By annotating the context of each predicted binding site (PBS, we classified them according to their positional coherence relative to other putative genomic structures such as start codons, RNA polymerase promoter elements and intergenic regions. We further used the Multiple EM for Motif Elicitation algorithm (MEME to further filter out low homology PBSs. In summary, 75 target-genes were identified, 34 of which have a higher confidence level. Among the identified genes, we found afeR itself, zwf, genes encoding glycosyltransferase activities, metallo-beta lactamases, and active transport-related proteins. Glycosyltransferases and Zwf (Glucose 6-phosphate-1-dehydrogenase might be directly involved in polysaccharide biosynthesis and attachment to minerals by At. ferrooxidans cells during the bioleaching process.

Bioinformatic Prediction of Gene Functions Regulated by Quorum Sensing in the Bioleaching Bacterium Acidithiobacillus ferrooxidans

Science.gov (United States)

Banderas, Alvaro; Guiliani, Nicolas

2013-01-01

The biomining bacterium Acidithiobacillus ferrooxidans oxidizes sulfide ores and promotes metal solubilization. The efficiency of this process depends on the attachment of cells to surfaces, a process regulated by quorum sensing (QS) cell-to-cell signalling in many Gram-negative bacteria. At. ferrooxidans has a functional QS system and the presence of AHLs enhances its attachment to pyrite. However, direct targets of the QS transcription factor AfeR remain unknown. In this study, a bioinformatic approach was used to infer possible AfeR direct targets based on the particular palindromic features of the AfeR binding site. A set of Hidden Markov Models designed to maintain palindromic regions and vary non-palindromic regions was used to screen for putative binding sites. By annotating the context of each predicted binding site (PBS), we classified them according to their positional coherence relative to other putative genomic structures such as start codons, RNA polymerase promoter elements and intergenic regions. We further used the Multiple EM for Motif Elicitation algorithm (MEME) to further filter out low homology PBSs. In summary, 75 target-genes were identified, 34 of which have a higher confidence level. Among the identified genes, we found afeR itself, zwf, genes encoding glycosyltransferase activities, metallo-beta lactamases, and active transport-related proteins. Glycosyltransferases and Zwf (Glucose 6-phosphate-1-dehydrogenase) might be directly involved in polysaccharide biosynthesis and attachment to minerals by At. ferrooxidans cells during the bioleaching process. PMID:23959118

A Comparative Analysis of Indigenous Research Guidelines to Inform Genomic Research in Indigenous Communities

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Jay Maddock

2012-05-01

Full Text Available BACKGROUND: Genetic research has potential benefits for improving health, such as identifying molecular characteristics of a disease, understanding disease prevalence and treatment, and developing treatments tailored to patients based on individual genetic characteristics of their disease. Indigenous people are often targeted for genetic research because genes are easier to study in communities that practice endogamy. Therefore, populations perceived to be more homogenous, such as Indigenous peoples, are ideal for genetic studies. While Indigenous communities remain the focal point of many genomic studies, some result in harm and unethical practice. Unfortunately, the harms of poorly formulated and unethical research involving Indigenous people have created barriers to participation that prevent critical and lifesaving research. These harms have led a number of Indigenous communities to develop guidelines for engaging with researchers to assist in safely bridging the gap between genetic research and Indigenous peoples.SPECIFIC AIMS: The specific aims of this study were: (1 to conduct an international review and comparison of Indigenous research guidelines that highlight topics regarding genetics and use of biological samples and identify commonalities and differences among ethical principles of concern to Indigenous peoples; and (2 develop policy recommendations for Indigenous populations interested in creating formal policies around the use of genetic information and protection of biological samples using data from specific aim 1.METHODS: A comparative analysis was performed to identify best research practices and recommendations for Indigenous groups from four countries: Canada, New Zealand, Australia, and the United States. The analysis examined commonalities in political relationships, which support self-determination among these Indigenous communities to control their data. Current international Indigenous guidelines were analyzed to review

Evaluation of diazinon pesticide biodegradation by isolated indigenous bacteria from contaminated soil

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Arezoo Alipour

2018-06-01

Discussion and conclusion: Results of this study revealed that degradation bacteria of diazinon exist in the places that used this insecticide and in the waste of industrial zone. It is expected that using these bacteria and biological resuscitation, it is possible to reduce some environmental hazardus issues of diazinon and also field application and determining the best formulation for bioramidation are essential in the future.

Bioleaching of fly ash from municipal solid waste incineration using kitchen waste saccharified solution as culture medium

International Nuclear Information System (INIS)

Wei, S.; Juan, W.; Qunhui, W.

2013-01-01

Summary: Reduced sugar in saccharified solution from kitchen waste was used as the carbon source. Domesticated A. niger AS 3.879C , which can withstand 20% of kitchen waste, was used as the inoculum in the bioleaching process of municipal solid waste incineration fly ash. The effect of reduced sugar concentration, fly ash concentration, and medium volume on the heavy metal extraction and yield of fly ash as well as the optimum bioleaching conditions; the inoculation amount of AS 3 .879C 1% (v/v), reduced sugar concentration of 80 g/l, fly ash concentration of 20 g/l, medium volume of 200 ml, and the addition of fly ash (20 g/l) after culturing for 4 days at 30 degree C and 140 r/min were obtained. Under the optimum condition, the extraction yield of the seven tested heavy metals are in the order of Cd > Zn > Cu > Mn > Pb > Cr > Fe; the extraction yield of Cd and Zn reached 88.7% and 73.1% respectively. Fly ash satisfied the Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes (GB 18598-2001) after heavy metal extraction. (author)

The politics of indigeneity: Indigenous strategies for inclusion in climate change negotiations

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Doolittle Amity

2010-01-01

Full Text Available Indigenous environmental activists have clearly articulated their views on global climate change policy. The content of these views was explored during the 10-day 2008 World Conservation Congress (WCC in Barcelona. Data were primarily collected through interviews and participant observation. In addition, policy statements and declarations made by indigenous environmental activists from 2000 to 2009 were analysed to place the perspectives of indigenous leaders and environmental activists in the context of their decade-long struggle to gain negotiating power at the United Nations Framework Convention on Climate Change. This study examines the rhetorical strategies indigenous leaders from around the world use to gain political recognition and legitimacy in climate change negotiations. Two core principles, relating to a particular representation of indigenous environmental knowledge are identified as fundamental rhetorical tools. These are a belief that the earth is a living being with rights and the conviction that it is the responsibility of indigenous peoples to protect the earth from over-exploitation. However, reference to indigenous environmental knowledge is not the only rhetorical mechanism used by indigenous leaders in the climate debates. When faced with specific United Nations policies to combat climate change that could have a profound impact on their land rights, some indigenous leaders adopt a more confrontational response. Fearing that new polices would reinforce historical trends of marginalisation, indigenous leaders seeking recognition in climate change debates speak less about their ecological knowledge and responsibility to the earth and more about their shared histories of political and economic marginalisation and land dispossession, experienced first through colonialism and more recently through globalisation.

Leaching characteristics of encapsulated controlled low-strength materials containing arsenic-bearing waste precipitates from refractory gold bioleaching.

Science.gov (United States)

Bouzalakos, S; Dudeney, A W L; Chan, B K C

2016-07-01

We report on the leaching of heavy elements from cemented waste flowable fill, known as controlled low-strength materials (CLSM), for potential mine backfill application. Semi-dynamic tank leaching tests were carried out on laboratory-scale monoliths cured for 28 days and tested over 64 days of leaching with pure de-ionised water as leachant. Mineral processing waste include flotation tailings from a Spanish nickel-copper sulphide concentrate, and two bioleach neutralisation precipitates (from processing at 35°C and 70°C) from a South African arsenopyrite concentrate. Encapsulated CLSM formulations were evaluated to assess the reduction in leaching by encapsulating a 'hazardous' CLSM core within a layer of relatively 'inert' CLSM. The effect of each bioleach waste in CLSM core and tailings in CLSM encapsulating medium, are assessed in combination and in addition to CLSM with ordinary silica sand. Results show that replacing silica sand with tailings, both as core and encapsulating matrix, significantly reduced leachability of heavy elements, particularly As (from 0.008-0.190 mg/l to 0.008-0.060 mg/l), Ba (from 0.435-1.540 mg/l to 0.050-0.565 mg/l), and Cr (from 0.006-0.458 mg/l to 0.004-0.229 mg/l), to below the 'Dutch List' of groundwater contamination intervention values. Arsenic leaching was inherently high from both bioleach precipitates but was significantly reduced to below guideline values with encapsulation and replacing silica sand with tailings. Tailings proved to be a valuable encapsulating matrix largely owing to small particle size and lower hydraulic conductivity reducing diffusion transport of heavy elements. Field-scale trials would be necessary to prove this concept of encapsulation in terms of scale and construction practicalities, and further geochemical investigation to optimise leaching performance. Nevertheless, this work substantiates the need for alternative backfill techniques for sustainable management of hazardous finely-sized bulk

The contribution of geography to disparities in preventable hospitalisations between indigenous and non-indigenous Australians.

Science.gov (United States)

Harrold, Timothy C; Randall, Deborah A; Falster, Michael O; Lujic, Sanja; Jorm, Louisa R

2014-01-01

To quantify the independent roles of geography and Indigenous status in explaining disparities in Potentially Preventable Hospital (PPH) admissions between Indigenous and non-Indigenous Australians. Analysis of linked hospital admission data for New South Wales (NSW), Australia, for the period July 1 2003 to June 30 2008. Age-standardised admission rates, and rate ratios adjusted for age, sex and Statistical Local Area (SLA) of residence using multilevel models. PPH diagnoses accounted for 987,604 admissions in NSW over the study period, of which 3.7% were for Indigenous people. The age-standardised PPH admission rate was 76.5 and 27.3 per 1,000 for Indigenous and non-Indigenous people respectively. PPH admission rates in Indigenous people were 2.16 times higher than in non-Indigenous people of the same age group and sex who lived in the same SLA. The largest disparities in PPH admission rates were seen for diabetes complications, chronic obstructive pulmonary disease and rheumatic heart disease. Both rates of PPH admission in Indigenous people, and the disparity in rates between Indigenous than non-Indigenous people, varied significantly by SLA, with greater disparities seen in regional and remote areas than in major cities. Higher rates of PPH admission among Indigenous people are not simply a function of their greater likelihood of living in rural and remote areas. The very considerable geographic variation in the disparity in rates of PPH admission between Indigenous and non-Indigenous people indicates that there is potential to reduce unwarranted variation by characterising outlying areas which contribute the most to this disparity.

Bio-dissolution of Ni, V and Mo from spent petroleum catalyst using iron oxidizing bacteria.

Science.gov (United States)

Pradhan, Debabrata; Kim, Dong J; Roychaudhury, Gautam; Lee, Seoung W

2010-01-01

Bioleaching studies of spent petroleum catalyst containing Ni, V and Mo were carried out using iron oxidizing bacteria. Various leaching parameters such as Fe(II) concentration, pulp density, pH, temperature and particle size were studied to evaluate their effects on the leaching efficiency as well as the kinetics of dissolution. The percentage of leaching of Ni and V were higher than Mo. The leaching process followed a diffusion controlled model and the product layer was observed to be impervious due to formation of ammonium jarosite (NH(4))Fe(3)(SO(4))(2)(OH)(6). Apart from this, the lower leaching efficiency of Mo was due to a hydrophobic coating of elemental sulfur over Mo matrix in the spent catalyst. The diffusivities of the attacking species for Ni, V and Mo were also calculated.

Indigenous Young People Transitioning from Out-of-Home Care (OOHC in Victoria, Australia: The Perspectives of Workers in Indigenous-Specific and Non-Indigenous Non-Government Services

Directory of Open Access Journals (Sweden)

Philip Mendes

2016-08-01

Full Text Available Indigenous children and young people are overrepresented in the Australian out-of-home care (OOHC system. To date, specific research has not been undertaken on workers' perspectives regarding the Indigenous-specific and non-Indigenous supports and services available to Indigenous young people exiting the system. This exploratory research involved focus group consultations with workers from seven child and family welfare agencies to examine the current support services available to Indigenous young people who are in or will be leaving out-of-home care in the State of Victoria. Findings suggest that Aboriginal Community Controlled Organisations (ACCOs play a positive role in working with non-Indigenous agencies to assist Indigenous care leavers. Participants identified some key strategies to improve outcomes, such as facilitating stronger relationships between Indigenous and non-Indigenous services, and improving the resourcing of ACCOs.

Survival of introduced phosphate-solubilizing bacteria (PSB) and their impact on microbial community structure during the phytoextraction of Cd-contaminated soil.

Science.gov (United States)

Jeong, Seulki; Moon, Hee Sun; Shin, Doyun; Nam, Kyoungphile

2013-12-15

This study was conducted to investigate whether or not phosphate-solubilizing bacteria (PSB) as a kind of plant growth promoting rhizobacteria enhance the uptake of Cd by plants. In addition, the effect of PSB augmentation during phytoextraction on the microbial community of indigenous soil bacteria was also studied. In the initial Cd-contaminated soil, the major phyla were Proteobacteria (35%), Actinobacteria (38%) and Firmicutes (8%). While Proteobacteria were dominant at the second and sixth week (41 and 54%, respectively) in inoculated soil, Firmicutes (mainly belonging to the Bacilli class-61%), dramatically increased in the eight-week soil. For the uninoculated soil, the proportion of α-Proteobacteria increased after eight weeks (32%). Interestingly, Actinobacteria class, which was originally present in the soil (37%), seemed to disappear during phytoremediation, irrespective of whether PSB was inoculated or not. Cluster analysis and Principal Component Analysis revealed that the microbial community of eight-week inoculated soil was completely separated from the other soil samples, due to the dramatic increase of Bacillus aryabhattai. These findings revealed that it took at least eight weeks for the inoculated Bacillus sp. to functionally adapt to the introduced soil, against competition with indigenous microorganisms in soil. An ecological understanding of interaction among augmented bacteria, plant and indigenous soil bacteria is needed, for proper management of phytoextraction. Copyright © 2013 Elsevier B.V. All rights reserved.

Indigenous Storytelling in Namibia

DEFF Research Database (Denmark)

Rodil, Kasper; Winschiers-Theophilus, Heike

2016-01-01

to understand indigenous youths’ own conception of storytelling the paper presents empirical data from a study with indigenous Khoisan children in Namibia. This is followed by a discussion of an effort of digitizing indigenous intangible cultural heritage in relation to technologies’ embodied bias...

Measuring cancer in indigenous populations.

Science.gov (United States)

Sarfati, Diana; Garvey, Gail; Robson, Bridget; Moore, Suzanne; Cunningham, Ruth; Withrow, Diana; Griffiths, Kalinda; Caron, Nadine R; Bray, Freddie

2018-05-01

It is estimated that there are 370 million indigenous peoples in 90 countries globally. Indigenous peoples generally face substantial disadvantage and poorer health status compared with nonindigenous peoples. Population-level cancer surveillance provides data to set priorities, inform policies, and monitor progress over time. Measuring the cancer burden of vulnerable subpopulations, particularly indigenous peoples, is problematic. There are a number of practical and methodological issues potentially resulting in substantial underestimation of cancer incidence and mortality rates, and biased survival rates, among indigenous peoples. This, in turn, may result in a deprioritization of cancer-related programs and policies among these populations. This commentary describes key issues relating to cancer surveillance among indigenous populations including 1) suboptimal identification of indigenous populations, 2) numerator-denominator bias, 3) problems with data linkage in survival analysis, and 4) statistical analytic considerations. We suggest solutions that can be implemented to strengthen the visibility of indigenous peoples around the world. These include acknowledgment of the central importance of full engagement of indigenous peoples with all data-related processes, encouraging the use of indigenous identifiers in national and regional data sets and mitigation and/or careful assessment of biases inherent in cancer surveillance methods for indigenous peoples. Copyright © 2018 Elsevier Inc. All rights reserved.

Bioleached sludge composting drastically reducing ammonia volatilization as well as decreasing bulking agent dosage and improving compost quality: A case study.

Science.gov (United States)

Hu, Weitong; Zheng, Guanyu; Fang, Di; Cui, Chunhong; Liang, Jianru; Zhou, Lixiang

2015-10-01

Sludge bioleaching technology with Acidithiobacillus species has been commercially adopted for improving advanced dewatering of sludge in China since 2010. However, up to now, little information on bioleached dewatered sludge (BS) composting is available. Here, we report the changes of physicochemical and biological properties in BS composting and evaluate compost product quality compared to conventional dewatered sludge (CS) composting in an engineering scale composting facility. The results showed that the amount of bulking agents required in BS composting was only about 10% of CS composting to obtain optimum moisture content, reducing about 700 kg bulking agents per ton fresh sludge. pH of BS composting mixture was slightly lower consistently by about 0.2-0.3 pH units than that in CS mixture in the first 30 days. Organic matter biodegradation in BS system mainly occurred in the first 9 days of composting. In spite of higher content of NH4(+)-N was found in BS mixture in related to CS mixture; unexpectedly the cumulative ammonia volatilization in the former was only 51% of the latter, indicating that BS composting drastically reduced nitrogen loss. Compared to CS composting system, the relative lower pH, the higher intensity of microbial assimilation, and the presence of water soluble Fe in BS system might jointly reduce ammonia volatilization. Consequently, BS compost product exhibited higher fertilizer values (N+P2O5+K2O=8.38%) as well as lower heavy metal levels due to the solubilization of sludge-borne heavy metals during bioleaching process. Therefore, composting of BS possesses more advantages over the CS composting process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genetics of Lactic Acid Bacteria

Science.gov (United States)

Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

The gambling behavior of indigenous Australians.

Science.gov (United States)

Hing, Nerilee; Breen, Helen; Gordon, Ashley; Russell, Alex

2014-06-01

The gambling activities of minority groups such as Indigenous peoples are usually culturally complex and poorly understood. To redress the scarcity of information and contribute to a better understanding of gambling by Indigenous people, this paper presents quantitative evidence gathered at three Australian Indigenous festivals, online and in several Indigenous communities. With support from Indigenous communities, the study collected and analyzed surveys from 1,259 self-selected Indigenous adults. Approximately 33 % of respondents gambled on card games while 80 % gambled on commercial gambling forms in the previous year. Gambling participation and involvement are high, particularly on electronic gaming machines (EGMs), the favorite and most regular form of gambling. Men are significantly more likely to participate in gambling and to gamble more frequently on EGMs, horse/dog races, sports betting and instant scratch tickets. This elevated participation and frequency of gambling on continuous forms would appear to heighten gambling risks for Indigenous men. This is particularly the case for younger Indigenous men, who are more likely than their older counterparts to gamble on EGMs, table games and poker. While distinct differences between the gambling behaviors of our Indigenous sample and non-Indigenous Australians are apparent, Australian Indigenous behavior appears similar to that of some Indigenous and First Nations populations in other countries. Although this study represents the largest survey of Indigenous Australian gambling ever conducted in New South Wales and Queensland, further research is needed to extend our knowledge of Indigenous gambling and to limit the risks from gambling for Indigenous peoples.

The World Indigenous Research Alliance (WIRA): Mediating and Mobilizing Indigenous Peoples' Educational Knowledge and Aspirations

Science.gov (United States)

Whitinui, Paul; McIvor, Onowa; Robertson, Boni; Morcom, Lindsay; Cashman, Kimo; Arbon, Veronica

2015-01-01

There is an Indigenous resurgence in education occurring globally. For more than a century Euro-western approaches have controlled the provision and quality of education to, and for Indigenous peoples. The World Indigenous Research Alliance (WIRA) established in 2012, is a grass-roots movement of Indigenous scholars passionate about making a…

Indigenous Australian Education and Globalisation

Science.gov (United States)

Brady, Wendy

1997-09-01

This article focuses on the impact of colonisation and its associated impact on Indigenous teaching and learning. Western European institutions have dominated Indigenous ways of knowing and in Australia this has led to barriers which restrict the participation of Aboriginal people in education systems. Globally Indigenous people are attempting to bring into the introduced educational systems culturally appropriate teaching and learning practices so that a more holistic approach to education can become the norm rather than the exception. The relationship between Indigenous knowledge and western European concepts of knowledge and knowing need to placed in a framework of mutual interaction so that not only do Indigenous people benefit, but so do non-Indigenous educators and students.

Why Indigenous Nations Studies?

Science.gov (United States)

Porter, Robert; Yellow Bird, Michael

2000-01-01

The development of a new Indigenous Nations Studies program at the University of Kansas is described. Success depended on a critical mass of Indigenous and non-Indigenous faculty and students that had a sense of political and social justice and understood the need for institutional change. The biggest challenge was countering the entrenched…

A new immobilized biomass technical adsorbent for uranium recovery from bioleach solutions in the mine

International Nuclear Information System (INIS)

Tsezos, Marios; Noh, S.H.

1988-01-01

A new type of metal adsorbent has been developed using inactive microbial biomass as the raw material. The adsorbent can be made to a desirable particle size. The particles have good mechanical strength and resistance to compression and consequently can be used in a packed bed resulting in a low pressure drop. The new biosorbents have been shown to maintain well the biosorptive properties of the immobilized biomass used for their production. We have tested successfully the new biosorbents for the recovery of uranium from actual bioleach solutions. (author)

About chemical and biological stimulation of bioleaching of 90Sr from different types of soil

International Nuclear Information System (INIS)

Buravlev, E.P.; Trishin, V.V.; Svyatun, O.V.; Berlizov, A.N.; Kim, In.S.; Ivanov, V.N.

2000-01-01

The results of investigation carried out in the frame of international cooperation between the NASU and KOSEF on the creation of effective methods of purification of radioactively polluted soil were performed. The influence of methanogenic, surface-reducing, nitrifying and thiobacilli and also their joint activity with different chemical ingredients on bioleaching of 90 Sr from typical South Korea red soil,artificially radioactively polluted by 90 Sr, and technogenically polluted by the radionuclides from influenced zone of ChNPP was studied, The presence of the largest effect of thiobacilli on soil was shown

Rethinking anaerobic As(III) oxidation in filters: Effect of indigenous nitrate respirers.

Science.gov (United States)

Cui, Jinli; Du, Jingjing; Tian, Haixia; Chan, Tingshan; Jing, Chuanyong

2018-04-01

Microorganisms play a key role in the redox transformation of arsenic (As) in aquifers. In this study, the impact of indigenous bacteria, especially the prevailing nitrate respirers, on arsenite (As(III)) oxidation was explored during groundwater filtration using granular TiO 2 and subsequent spent TiO 2 anaerobic landfill. X-ray absorption near edge structure spectroscopy analysis showed As(III) oxidation (46% in 10 days) in the presence of nitrate in the simulated anaerobic landfills. Meanwhile, iron (Fe) species on the spent TiO 2 were dominated by amorphous ferric arsenate, ferrihydrite and goethite. The Fe phase showed no change during the anaerobic landfill incubation. Batch incubation experiments implied that the indigenous bacteria completely oxidized As(III) to arsenate (As(V)) in 10 days using nitrate as the terminal electron acceptor under anaerobic conditions. The bacterial community analysis indicated that various kinds of microbial species exist in groundwater matrix. Phylogenetic tree analysis revealed that Proteobacteria was the dominant phylum, with Hydrogenophaga (34%), Limnohabitans (16%), and Simplicispira (7%) as the major bacterial genera. The nitrate respirers especially from the Hydrogenophaga genus anaerobically oxidized As(III) using nitrate as an electron acceptor instead of oxygen. Our study implied that microbes can facilitate the groundwater As oxidation using nitrate on the adsorptive media. Copyright © 2017 Elsevier Ltd. All rights reserved.

The politics of indigeneity: Indigenous strategies for inclusion in climate change negotiations

OpenAIRE

Doolittle Amity

2010-01-01

Indigenous environmental activists have clearly articulated their views on global climate change policy. The content of these views was explored during the 10-day 2008 World Conservation Congress (WCC) in Barcelona. Data were primarily collected through interviews and participant observation. In addition, policy statements and declarations made by indigenous environmental activists from 2000 to 2009 were analysed to place the perspectives of indigenous leaders and environmental activists in t...

Reclaiming Indigenous identities: Culture as strength against suicide among Indigenous youth in Canada.

Science.gov (United States)

Barker, Brittany; Goodman, Ashley; DeBeck, Kora

2017-06-16

In Canada, Indigenous youth suicide represents one of several health disparities burdening Indigenous populations, and like many other of these disparities, can be understood as an expression of societal, historical, cultural and familial trauma. As the number of Indigenous youth who take their own lives every year in Canada continues to far exceed national averages, it appears that conventional suicide prevention efforts remain ineffective among this population. A growing body of research argues that conventional interventions, largely rooted in Western individual-level behavioural change frameworks, are culturally discordant with Indigenous paradigms. In response, some Indigenous communities are turning to cultural revitalization as a holistic community-driven response to suicide prevention and treatment. The following commentary explores the emerging evidence base for "culture as treatment" - a novel approach to suicide that emphasizes the significance of interconnectedness in healing, alongside the revitalization of traditional values to reclaim community wellness. In doing so, we seek to contribute to a changing discourse surrounding Indigenous youth suicide by acknowledging culture as strength against this national crisis.

SCHOOL, INDIGENOUS AND WESTERN CULTURES: REFLEXIONS TO THINK THE EDUCATION IN THE INDIGENOUS SCHOOLS

Directory of Open Access Journals (Sweden)

Cláudia Pereira Antunes

2009-12-01

Full Text Available The education in the indigenous schools, even though it is build within the legal framework of the State and a modern concept of education, demands new comprehensions from the western society not only in its relation with the indigenous education, but also in its relation with the indigenous people. Because of its condition as a mediator between two different forms of thinking, the indigenous school also represents a fertile ground to think about the western conceptions of education. This article is dedicated to a deeper reflection about some aspects of the relation between the western society, based on rationality and science, and the indian people in the construction of the indigenous schools.

[The contribution of indigenous community health workers to special healthcare for Brazilian indigenous peoples].

Science.gov (United States)

Diehl, Eliana Elisabeth; Langdon, Esther Jean; Dias-Scopel, Raquel Paiva

2012-05-01

Indigenous community health workers are part of a strategy developed by Brazil in the last two decades to promote a special healthcare model for indigenous peoples. Their role is designed to deal with various aspects of the special health policy, including the link between the heath team and the community and mediation between scientific and indigenous medical knowledge. Despite a significant increase in the number of indigenous community health workers in recent years, an evaluation of their responsibilities and contributions to the success of special care had not been conducted previously. This article, based on a literature review and original research by the authors, analyzes the role of the indigenous community health workers vis-à-vis their training and participation in health teams in different contexts in Brazil. Considering the importance assigned to the role of indigenous community health workers, this analysis reveals various ambiguities and contradictions that hinder both their performance and their potential contribution to the special health services.

Anaerobic bioleaching of metals from waste activated sludge

KAUST Repository

Meulepas, Roel J W

2015-05-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342μgg-1 of copper, 487μgg-1 of lead, 793μgg-1 of zinc, 27μgg-1 of nickel and 2.3μgg-1 of cadmium. During the anaerobic acidification of 3gdry weightL-1 waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

Mouthguards: does the indigenous microbiome play a role in maintaining oral health?

Science.gov (United States)

Kumar, Purnima S; Mason, Matthew R

2015-01-01

The existence of symbiotic relationships between bacteria and their hosts in various ecosystems have long been known to science. The human body also hosts vast numbers of bacteria in several habitats. Emerging evidence from the gastro-intestinal tract, genito-urinary tract and respiratory indicates that there are several health benefits to hosting a complex and diverse microbial community. Bacteria colonize the oral cavity within a few minutes after birth and form stable communities. Our knowledge of the oral microbiome has expanded exponentially with development of novel exploratory methods that allow us to examine diversity, structure, function, and topography without the need to cultivate the individual components of the biofilm. The purpose of this perspective, therefore, is to examine the strength of current evidence supporting a role for the oral microbiome in maintaining oral health. While several lines of evidence are emerging to suggest that indigenous oral microbiota may have a role in immune education and preventing pathogen expansion, much more work is needed to definitively establish whether oral bacteria do indeed contribute to sustaining oral health, and if so, the mechanisms underlying this role.

Mouthguards: Does the indigenous microbiome play a role in maintaining oral health?

Directory of Open Access Journals (Sweden)

Purnima S Kumar

2015-05-01

Full Text Available The existence of symbiotic relationships between bacteria in different ecosystems and their host niches have long been known to science. The human body also hosts vast numbers of bacteria in several habitats. Emerging evidence from the gastro-intestinal tract, genito-urinary tract and respiratory indicates that there are several health benefits to hosting a complex and diverse microbial community i. Bacteria colonize the oral cavity within a few minutes after birth and form stable communities . Our knowledge of the oral microbiome has expanded exponentially with development of novel exploratory methods that allow us to examine diversity, structure, function and topography without the need to cultivate the individual components of the biofilm. The purpose of this perspective, therefore, is to examine the strength of current evidence supporting a role for the oral microbiome in maintaining oral health. While several lines of evidence are emerging to suggest that indigenous oral microbiota may have a role in immune education and preventing pathogen expansion, much more work is needed to definitively establish whether oral bacteria do indeed contribute to sustaining oral health, and if so, the mechanisms underlying this role.

Amenability of low-grade uranium towards column bioleaching by acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Abhilash; Mehta, K.D.; Kumar, V.; Pandey, B.D.; Tamrakar, P.K.

2007-01-01

R and D studies were carried out at NML using Acidithiobacillus ferrooxidans (Ac.Tf) in column for the bio-recovery of uranium from the low-grade uranium ore containing 0.024% U 3 O 8 of Turamdih mines, Singhbhum. A recovery of 55.48% uranium was obtained in bio-leaching as against ∼ 44.9% in sterile control in 30 days at 1.7 pH in a column containing 2.5kg ore of particle size mainly in the range 5-1mm. In the large scale column, leaching with 80kg ore of particle size ∼ 0.5cm, uranium bio-recovery was found to be 69.8% in comparison to a recovery of 55% in control set at 1.7 pH in 50 days. The uranium recoveries followed indirect leaching mechanism. (author)

Isolation, identification and diesel-oil biodegradation capacities of indigenous hydrocarbon-degrading strains of Cellulosimicrobium cellulans and Acinetobacter baumannii from tarball at Terengganu beach, Malaysia.

Science.gov (United States)

Nkem, Bruno Martins; Halimoon, Normala; Yusoff, Fatimah Md; Johari, Wan Lufti Wan; Zakaria, Mohamad Pauzi; Medipally, Srikanth Reddy; Kannan, Narayanan

2016-06-15

In this study, we isolated two indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC-MS, showed diesel-oil alkanes were degraded an average 64.4% by C. cellulans and 58.1% by A. baumannii with medium optical density reaching 0.967 (C. cellulans) and 1.515 (A. baumannii) in minimal salt media at 32°C for 10days. Individual diesel-oil alkanes were degraded between 10%-95.4% by C. cellulans and 0.2%-95.9% by A. baumannii. Both strains utilized diesel-oil for growth. The study suggests both strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Visual Profile of Queensland Indigenous Children.

Science.gov (United States)

Hopkins, Shelley; Sampson, Geoff P; Hendicott, Peter L; Wood, Joanne M

2016-03-01

Little is known about the prevalence of refractive error, binocular vision, and other visual conditions in Australian Indigenous children. This is important given the association of these visual conditions with reduced reading performance in the wider population, which may also contribute to the suboptimal reading performance reported in this population. The aim of this study was to develop a visual profile of Queensland Indigenous children. Vision testing was performed on 595 primary schoolchildren in Queensland, Australia. Vision parameters measured included visual acuity, refractive error, color vision, nearpoint of convergence, horizontal heterophoria, fusional vergence range, accommodative facility, AC/A ratio, visual motor integration, and rapid automatized naming. Near heterophoria, nearpoint of convergence, and near fusional vergence range were used to classify convergence insufficiency (CI). Although refractive error (Indigenous, 10%; non-Indigenous, 16%; p = 0.04) and strabismus (Indigenous, 0%; non-Indigenous, 3%; p = 0.03) were significantly less common in Indigenous children, CI was twice as prevalent (Indigenous, 10%; non-Indigenous, 5%; p = 0.04). Reduced visual information processing skills were more common in Indigenous children (reduced visual motor integration [Indigenous, 28%; non-Indigenous, 16%; p < 0.01] and slower rapid automatized naming [Indigenous, 67%; non-Indigenous, 59%; p = 0.04]). The prevalence of visual impairment (reduced visual acuity) and color vision deficiency was similar between groups. Indigenous children have less refractive error and strabismus than their non-Indigenous peers. However, CI and reduced visual information processing skills were more common in this group. Given that vision screenings primarily target visual acuity assessment and strabismus detection, this is an important finding as many Indigenous children with CI and reduced visual information processing may be missed. Emphasis should be placed on identifying

Patterns of drug dependence in a Queensland (Australia) sample of Indigenous and non-Indigenous people who inject drugs.

Science.gov (United States)

Smirnov, Andrew; Kemp, Robert; Ward, James; Henderson, Suzanna; Williams, Sidney; Dev, Abhilash; Najman, Jake M

2016-09-01

Despite over-representation of Indigenous Australians in sentinel studies of injecting drug use, little is known about relevant patterns of drug use and dependence. This study compares drug dependence and possible contributing factors in Indigenous and non-Indigenous Australians who inject drugs. Respondent-driven sampling was used in major cities and 'peer recruitment' in regional towns of Queensland to obtain a community sample of Indigenous (n = 282) and non-Indigenous (n = 267) injectors. Data are cross sectional. Multinomial models were developed for each group to examine types of dependence on injected drugs (no dependence, methamphetamine-dependent only, opioid-dependent only, dependent on methamphetamine and opioids). Around one-fifth of Indigenous and non-Indigenous injectors were dependent on both methamphetamine and opioids in the previous 12 months. Psychological distress was associated with dual dependence on these drugs for Indigenous [adjusted relative risk (ARR) 4.86, 95% confidence interval (CI) 2.08-11.34] and non-Indigenous (ARR 4.14, 95% CI 1.59-10.78) participants. Unemployment (ARR 8.98, 95% CI 2.25-35.82) and repeated (> once) incarceration as an adult (ARR 3.78, 95% CI 1.43-9.97) were associated with dual dependence for Indigenous participants only. Indigenous participants had high rates of alcohol dependence, except for those dependent on opioids only. The drug dependence patterns of Indigenous and non-Indigenous people who inject drugs were similar, including the proportions dependent on both methamphetamine and opioids. However, for Indigenous injectors, there was a stronger association between drug dependence and contextual factors such as unemployment and incarceration. Expansion of treatment options and community-level programs may be required. [Smirnov A, Kemp R, Ward J, Henderson S, Williams S, Dev A, Najman J M. Patterns of drug dependence in a Queensland (Australia) sample of Indigenous and non-Indigenous people who

Absence of disparities in anthropometric measures among Chilean indigenous and non-indigenous newborns

Science.gov (United States)

2010-01-01

Background Studies throughout North America and Europe have documented adverse perinatal outcomes for racial/ethnic minorities. Nonetheless, the contrast in newborn characteristics between indigenous and non-indigenous populations in Latin America has been poorly characterized. This is due to many challenges, including a lack of vital registration information on ethnicity. The objective of this study was to analyze trends in anthropometric measures at birth in Chilean indigenous (Mapuche) and non-indigenous children over a 5-year period. Methods We examined weight and length at birth using information available through a national data base of all birth records for the years 2000 through 2004 (n = 1,166.513). Newborns were classified ethnically according to the origins of the parents' last names. Result The average birthweight was stable over the 5 year period with variations of less than 20 g in each group, and with mean values trivially higher in indigenous newborns. The proportion weighing less than 2500 g at birth increased modestly from 5.2% to 5.6% in non-indigenous newborns whereas the indigenous births remained constant at 5.2%. In multiple regression analyses, adjusting flexibly for gestational age and maternal characteristics, the occurrence of an indigenous surname added only 14 g to an average infant's birthweight while holding other factors constant. Results for length at birth were similar, and adjusted time trend variation in both outcomes was trivially small after adjustment. Anthropometric indexes at birth in Chile are quite favorable by international standards. Conclusion There is only a trivial degree of ethnic disparity in these values, in contrast to conditions for ethnic minorities in other countries. Moreover, these values remained roughly constant over the 5 years of observation in this study. PMID:20598150

Bio-processing of copper from combined smelter dust and flotation concentrate: a comparative study on the stirred tank and airlift reactors.

Science.gov (United States)

Vakylabad, Ali Behrad; Schaffie, Mahin; Ranjbar, Mohammad; Manafi, Zahra; Darezereshki, Esmaeel

2012-11-30

To scrutinize the influence of the design and type of the bioreactors on the bioleaching efficiency, the bioleaching were evaluated in a batch airlift and a batch stirred tank bioreactors with mixed mesophilic and mixed moderately thermophilic bacteria. According to the results, maximum copper recoveries were achieved using the cultures in the stirred tank bioreactors. It is worth noting that the main phase of the flotation concentrate was chalcopyrite (as a primary sulphide), but the smelter dust mainly contained secondary copper sulphides such as Cu(2)S, CuS, and Cu(5)FeS(4).Under optimum conditions, copper dissolution from the combined flotation concentrate and smelter dust (as an environmental hazard) reached 94.50% in the STR, and 88.02% in the airlift reactor with moderately thermophilic, after 23 days. Also, copper extractions calculated for the bioleaching using mesophilic bacteria were 48.73% and 37.19% in the STR (stirred tank reactor) and the airlift bioreactor, respectively. In addition, the SEM/EDS, XRD, chemical, and mineralogical analyses and studies confirmed the above results. Copyright © 2012 Elsevier B.V. All rights reserved.

Emerging Ideas for Innovation in Indigenous Education: A Research Synthesis of Indigenous Educative Roles in Mainstream and Flexi Schools

Science.gov (United States)

Shay, Marnee

2017-01-01

The Indigenous education agenda in Australia remains focused on mainstream schooling contexts. Although overlooked in Indigenous education discourse, flexi schools appear to be engaging with disproportionately high numbers of Indigenous students and staff. The educative roles of Indigenous peoples in broader Indigenous education discourse are…

Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

International Nuclear Information System (INIS)

Malkin, A.J.

2010-01-01

The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

Prospective role of indigenous Exiguobacterium profundum PT2 in arsenic biotransformation and biosorption by planktonic cultures and biofilms.

Science.gov (United States)

Saba; Andreasen, R; Li, Y; Rehman, Y; Ahmed, M; Meyer, R L; Sabri, A N

2018-02-01

The aim of this study was to analyse arsenic (As) transformation and biosorption by indigenous As-resistant bacteria both in planktonic and biofilm modes of growth. As-resistant bacteria were isolated from industrial waste water and strain PT2, and identified as Exiguobacterium profundum through 16S rRNA gene sequencing was selected for further study. As transformation and biosorption by E. profundumPT2 was determined by HPLC-ICP-MS analysis. Planktonic cultures reduced 3·73 mmol l -1 As 5+ into As 3+ from artificial waste water effluent after 48-h incubation. In case of biosorption, planktonic cultures and biofilms exhibited 25·2 and 29·4 mg g -1 biomass biosorption, respectively. As biosorption kinetics followed Freundlich isotherm and pseudo second-order model. Biofilm formation peaked after 3 days of incubation, and in the presence of As stress, biofilm formation was significantly affected in contrast to control (P biofilms with an increased demand of nutrients was revealed by minimum roughness and maximum surface to biovolume ratio measured through CLSM analysis. Indigenous As-resistant E. profundumPT2 was found capable of As transformation and biosorption both in the form of planktonic cultures and biofilms. Indigenous biofilm forming E. profundum PT2 revealing As biosorption and biotransformation potential is presented an eco-friendly and cost-effective source for As remediation that can be implemented for waste water treatment. © 2017 The Society for Applied Microbiology.

Bio-processing of copper from combined smelter dust and flotation concentrate: A comparative study on the stirred tank and airlift reactors

Energy Technology Data Exchange (ETDEWEB)

Vakylabad, Ali Behrad, E-mail: alibehzad86@yahoo.co.uk [Department of Mining Engineering, Shahid Bahonar University, Kerman (Iran, Islamic Republic of); Engineers of Nano and Bio Advanced Sciences Company (ENBASCo.), ATIC, Mohaghegh University (Iran, Islamic Republic of); Schaffie, Mahin [Department of Chemical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Mineral Industries Research Centre (MIRC), Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ranjbar, Mohammad [Department of Mining Engineering, Shahid Bahonar University, Kerman (Iran, Islamic Republic of); Mineral Industries Research Centre (MIRC), Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Manafi, Zahra [Sarcheshmeh Copper Complex, National Iranian Copper Industry Company (Iran, Islamic Republic of); Darezereshki, Esmaeel [Mineral Industries Research Centre (MIRC), Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Energy and Environmental Engineering Research Center (EERC), Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2012-11-30

Highlights: Black-Right-Pointing-Pointer Flotation concentrate and smelter dust were sampled and combined. Black-Right-Pointing-Pointer Copper bioleaching from the combined was investigated. Black-Right-Pointing-Pointer Two bio-reactors were investigated and optimized: stirred and airlift. Black-Right-Pointing-Pointer STRs had better technical conditions and situations for bacterial leaching. - Abstract: To scrutinize the influence of the design and type of the bioreactors on the bioleaching efficiency, the bioleaching were evaluated in a batch airlift and a batch stirred tank bioreactors with mixed mesophilic and mixed moderately thermophilic bacteria. According to the results, maximum copper recoveries were achieved using the cultures in the stirred tank bioreactors. It is worth noting that the main phase of the flotation concentrate was chalcopyrite (as a primary sulphide), but the smelter dust mainly contained secondary copper sulphides such as Cu{sub 2}S, CuS, and Cu{sub 5}FeS{sub 4}.Under optimum conditions, copper dissolution from the combined flotation concentrate and smelter dust (as an environmental hazard) reached 94.50% in the STR, and 88.02% in the airlift reactor with moderately thermophilic, after 23 days. Also, copper extractions calculated for the bioleaching using mesophilic bacteria were 48.73% and 37.19% in the STR (stirred tank reactor) and the airlift bioreactor, respectively. In addition, the SEM/EDS, XRD, chemical, and mineralogical analyses and studies confirmed the above results.

Mesophilic leaching of copper sulphide sludge

Directory of Open Access Journals (Sweden)

VLADIMIR B. CVETKOVSKI

2009-02-01

Full Text Available Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 µm in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32 °C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

Bio-processing of copper from combined smelter dust and flotation concentrate: A comparative study on the stirred tank and airlift reactors

International Nuclear Information System (INIS)

Vakylabad, Ali Behrad; Schaffie, Mahin; Ranjbar, Mohammad; Manafi, Zahra; Darezereshki, Esmaeel

2012-01-01

Highlights: ► Flotation concentrate and smelter dust were sampled and combined. ► Copper bioleaching from the combined was investigated. ► Two bio-reactors were investigated and optimized: stirred and airlift. ► STRs had better technical conditions and situations for bacterial leaching. - Abstract: To scrutinize the influence of the design and type of the bioreactors on the bioleaching efficiency, the bioleaching were evaluated in a batch airlift and a batch stirred tank bioreactors with mixed mesophilic and mixed moderately thermophilic bacteria. According to the results, maximum copper recoveries were achieved using the cultures in the stirred tank bioreactors. It is worth noting that the main phase of the flotation concentrate was chalcopyrite (as a primary sulphide), but the smelter dust mainly contained secondary copper sulphides such as Cu 2 S, CuS, and Cu 5 FeS 4 .Under optimum conditions, copper dissolution from the combined flotation concentrate and smelter dust (as an environmental hazard) reached 94.50% in the STR, and 88.02% in the airlift reactor with moderately thermophilic, after 23 days. Also, copper extractions calculated for the bioleaching using mesophilic bacteria were 48.73% and 37.19% in the STR (stirred tank reactor) and the airlift bioreactor, respectively. In addition, the SEM/EDS, XRD, chemical, and mineralogical analyses and studies confirmed the above results.

A Digital Indigenous Knowledge Preservation Framework

DEFF Research Database (Denmark)

Maasz, Donovan; Winschiers-Theophilus, Heike; Stanley, Colin

2018-01-01

Indigenous Knowledge (IK) preservation and management has been taken up as a serious endeavor by various governments who have realized the value of IK as well as the opportunities given by emerging technologies. Considering the various phases and activities of indigenous knowledge management which...... the indigenous knowledge digitization process, namely, codesign, conceptualization, collection, correction, curation, circulation, and creation of knowledge. We exemplify the application of the model with technologies currently developed under an indigenous knowledge holder’s toolkit promoting the agency...... of digitalizing indigenous knowledge across the phases....

Indigenous Educational Attainment in Canada

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Catherine E. Gordon

2014-06-01

Full Text Available In this article, the educational attainment of Indigenous peoples of working age (25 to 64 years in Canada is examined. This diverse population has typically had lower educational levels than the general population in Canada. Results indicate that, while on the positive side there are a greater number of highly educated Indigenous peoples, there is also a continuing gap between Indigenous and non-Indigenous peoples. Data also indicate that the proportion with less than high school education declined, which corresponds with a rise of those with a PSE; the reverse was true in 1996. Despite these gains, however, the large and increasing absolute numbers of those without a high school education is alarming. There are intra-Indigenous differences: First Nations with Indian Status and the Inuit are not doing as well as non-Status and Métis peoples. Comparisons between the Indigenous and non-Indigenous populations reveal that the documented gap in post-secondary educational attainment is at best stagnant. Out of the data analysis, and based on the history of educational policy, we comment on the current reform proposed by the Government of Canada, announced in February of 2014, and propose several policy recommendations to move educational attainment forward.

Drug and alcohol use and treatment for Australian Indigenous and non-Indigenous prisoners: demand reduction strategies.

Science.gov (United States)

Dolan, Kate; Rodas, Ana; Bode, Adam

2015-01-01

The purpose of this paper is to compare the use of drugs and alcohol by Indigenous and non-Indigenous prisoners and examine relevant treatment in Australian prisons. Prison authorities were surveyed about alcohol and drug use by prisoners prior to and during imprisonment and drug and alcohol treatment programs in prison. The literature was review for information on alcohol and drug use and treatment in Australian prisons. In 2009, over 80 percent of Indigenous and non-Indigenous inmates smoked. Prior to imprisonment, many Indigenous and non-Indigenous inmates drank alcohol at risky levels (65 vs 47 percent) and used illicit drugs (over 70 percent for both groups). Reports of using heroin (15 vs 21 percent), ATS (21 vs 33 percent), cannabis (59 vs 50 percent) and injecting (61 vs 53 percent) were similarly high for both groups. Prison-based programs included detoxification, Opioid Substitution Treatment, counselling and drug free units, but access was limited especially among Indigenous prisoners. Drug and alcohol use was a significant issue in Australian prisons. Prisoners were over five times more likely than the general population to have a substance use disorder. Imprisonment provides an important opportunity for rehabilitation for offenders. This opportunity is especially relevant to Indigenous prisoners who were more likely to use health services when in prison than in the community and given their vast over representations in prison populations. Given the effectiveness of treatment in reducing re-offending rates, it is important to expand drug treatment and especially culturally appropriate treatment programs for Indigenous inmates. Very little is known about Indigenous specific drug and alcohol programs in Australian prisons.

Re-vitalizing an indigenous language

DEFF Research Database (Denmark)

Hansen, Annette Skovsted

2014-01-01

The re-vitalization of indigenous languages depend on political and legal support and the imple-mentation of language rights depend on knowledge of vocabulary and grammar structures of the individual languages. Throughout the nineteenth century world, compilers of dictionaries adapted indigenous...... languages to match standards defined in nation-building and, thereby, enabled latent possibilities for indigenous populations to re-vitalize their languages in connection with the United Nations Year for Indigenous Peoples in 1993, and the first United Nations Decade for Indigenous Peoples, 1995......–2004. This article focuses on dictionaries of the languages of the Ainu populations in the borderlands between the nation-states Japan and Russia. The main argument is that the Ainu Cultural Promotion Act promulgated in 1997 had a significant impact on the production and purpose of Ainu dictionaries...

Enhancing gold recovery from electronic waste via lixiviant metabolic engineering in Chromobacterium violaceum

Science.gov (United States)

Tay, Song Buck; Natarajan, Gayathri; Rahim, Muhammad Nadjad bin Abdul; Tan, Hwee Tong; Chung, Maxey Ching Ming; Ting, Yen Peng; Yew, Wen Shan

2013-01-01

Conventional leaching (extraction) methods for gold recovery from electronic waste involve the use of strong acids and pose considerable threat to the environment. The alternative use of bioleaching microbes for gold recovery is non-pollutive and relies on the secretion of a lixiviant or (bio)chemical such as cyanide for extraction of gold from electronic waste. However, widespread industrial use of bioleaching microbes has been constrained by the limited cyanogenic capabilities of lixiviant-producing microorganisms such as Chromobacterium violaceum. Here we show the construction of a metabolically-engineered strain of Chromobacterium violaceum that produces more (70%) cyanide lixiviant and recovers more than twice as much gold from electronic waste compared to wild-type bacteria. Comparative proteome analyses suggested the possibility of further enhancement in cyanogenesis through subsequent metabolic engineering. Our results demonstrated the utility of lixiviant metabolic engineering in the construction of enhanced bioleaching microbes for the bioleaching of precious metals from electronic waste. PMID:23868689

Bioleaching of uranium in batch stirred tank reactor: Process optimization using Box–Behnken design

International Nuclear Information System (INIS)

Eisapour, M.; Keshtkar, A.; Moosavian, M.A.; Rashidi, A.

2013-01-01

Highlights: ► High amount of uranium recovery achieved using Acidithiobacillus ferrooxidans. ► ANOVA shows individual variables and their squares are statistically significant. ► The model can accurately predict the behavior of uranium recovery. ► The model shows that pulp density has the greatest effect on uranium recovery. - Abstract: To design industrial reactors, it is important to identify and optimize the effective parameters of the process. Therefore, in this study, a three-level Box–Behnken factorial design was employed combining with a response surface methodology to optimize pulp density, agitation speed and aeration rate in uranium bioleaching in a stirred tank reactor using a pure native culture of Acidithiobacillus ferrooxidans. A mathematical model was then developed by applying the least squares method using the software Minitab Version 16.1.0. The second order model represents the uranium recovery as a function of pulp density, agitation speed and aeration rate. An analysis of variance was carried out to investigate the effects of individual variables and their combined interactive effects on uranium recovery. The results showed that the linear and quadratic terms of variables were statistically significant whilst the interaction terms were statistically insignificant. The model estimated that a maximum uranium extraction (99.99%) could be obtained when the pulp density, agitation speed and aeration rate were set at optimized values of 5.8% w/v, 510 rpm and 250 l/h, respectively. A confirmatory test at the optimum conditions resulted in a uranium recovery of 95%, indicating a marginal error of 4.99%. Furthermore, control tests were performed to demonstrate the effect of A. ferrooxidans in uranium bioleaching process and showed that the addition of this microorganism greatly increases the uranium recovery

[Differences in mortality between indigenous and non-indigenous persons in Brazil based on the 2010 Population Census].

Science.gov (United States)

Campos, Marden Barbosa de; Borges, Gabriel Mendes; Queiroz, Bernardo Lanza; Santos, Ricardo Ventura

2017-06-12

There have been no previous estimates on differences in adult or overall mortality in indigenous peoples in Brazil, although such indicators are extremely important for reducing social iniquities in health in this population segment. Brazil has made significant strides in recent decades to fill the gaps in data on indigenous peoples in the national statistics. The aim of this paper is to present estimated mortality rates for indigenous and non-indigenous persons in different age groups, based on data from the 2010 Population Census. The estimates used the question on deaths from specific household surveys. The results indicate important differences in mortality rates between indigenous and non-indigenous persons in all the selected age groups and in both sexes. These differences are more pronounced in childhood, especially in girls. The indicators corroborate the fact that indigenous peoples in Brazil are in a situation of extreme vulnerability in terms of their health, based on these unprecedented estimates of the size of these differences.

Human Rights and Indigenous Peoples

Directory of Open Access Journals (Sweden)

Garth Nettheim

2009-09-01

Full Text Available The paper begins by noting the low level of reference to Indigenous Australians in the Commonwealth Constitution at the start of Federation, and goes on to discuss the limits to what was achieved by the 1967 amendments. The situation represents a marked contrast with the USA and Canada in terms of treaties and constitutional recognition. In Australia, particularly during the period of the ‘Reconciliation’ process in the 1990s, important steps were taken by Indigenous Australians to identify items of ‘unfinished business’ in a ‘Statement of Indigenous Rights’. But there has been limited progress to meet these aspirations. And Australian law still lacks a tradition of recognition of human rights generally, let alone Indigenous rights. International law, too, largely lacked recognition of human rights, generally prior to the adoption in 1945 of the Charter of the United Nations. The brief references in the Charter were subsequently developed in a range of declarations and of treaties. These applied to people generally, with scant reference to Indigenous peoples. But, since the 1970s, there has been growing international recognition of the rights of Indigenous peoples under existing declarations and treaties. Since the 1990s, in particular, the UN system has established specific mechanisms for addressing such issues. On 13 September 2007, the General Assembly finally adopted a Declaration on the Rights of Indigenous Peoples.

Culturable heavy metal-resistant and plant growth promoting bacteria in V-Ti magnetite mine tailing soil from Panzhihua, China.

Directory of Open Access Journals (Sweden)

Xiumei Yu

Full Text Available To provide a basis for using indigenous bacteria for bioremediation of heavy metal contaminated soil, the heavy metal resistance and plant growth-promoting activity of 136 isolates from V-Ti magnetite mine tailing soil were systematically analyzed. Among the 13 identified bacterial genera, the most abundant genus was Bacillus (79 isolates out of which 32 represented B. subtilis and 14 B. pumilus, followed by Rhizobium sp. (29 isolates and Ochrobactrum intermedium (13 isolates. Altogether 93 isolates tolerated the highest concentration (1000 mg kg(-1 of at least one of the six tested heavy metals. Five strains were tolerant against all the tested heavy metals, 71 strains tolerated 1,000 mg kg(-1 cadmium whereas only one strain tolerated 1,000 mg kg(-1 cobalt. Altogether 67% of the bacteria produced indoleacetic acid (IAA, a plant growth-promoting phytohormone. The concentration of IAA produced by 53 isolates was higher than 20 µg ml(-1. In total 21% of the bacteria produced siderophore (5.50-167.67 µg ml(-1 with two Bacillus sp. producing more than 100 µg ml(-1. Eighteen isolates produced both IAA and siderophore. The results suggested that the indigenous bacteria in the soil have beneficial characteristics for remediating the contaminated mine tailing soil.

An Indigenous Academic Perspective to Preserving and Promoting Indigenous Knowledge and Traditions: A Fiji Case Study

Science.gov (United States)

Ali, Wahab

2017-01-01

Indigenous knowledge is multidimensional encompassing the beliefs, practices, arts, spirituality and other forms of traditional and cultural experiences that belong to Indigenous communities globally. In order to protect, preserve and recognize the knowledge of the Indigenous people of Fiji, known as the iTaukei, the University of Fiji has…

Symbiotic Properties of Sinorhizobium Fredii, J-TGS50 an Indonesian Soybean Nodule Forming Bacteria

International Nuclear Information System (INIS)

Setiyo Hadi Waluyo

2004-01-01

Green House experiments were conducted to study symbiotic properties of Sinorhizobium Fredii, J-TGS50. Sinorhizobium Fredii USDA 192, USDA 201, USDA 205, USDA 206, USDA 217 and Bradyrhizobium japonicum USDA 110 were used as references. Yeast extract mannitol broth culture of the bacteria were made and used as inoculation for several local and imported soybean varieties used in this study. Plants were harvested at 20 days after inoculation. Number of nodules were counted, fresh weight of nodules and shoot were determined. S. Fredii J-TGS50 and S. Fredii USDA 192, USDA 201, USDA 205, USDA 206, USDA 217 were found different in their symbiotic properties. S. Fredii J-TGS50 formed nodules on same imported soybean. While there were no nodules obtained from the plant inoculated with S. Fredii USDA 192, USDA 201, USDA 205, USDA 206, USDA 217. S. Fredii J-TGS50 and recommended B. Japonicum USDA 110 formed nodule on several local soybean varieties. There was no differences between those two bacteria either in nodulation efficiency or in the effectiveness of the formed nodules. Results of this study can be concluded that S. Fredii, J-TGS50 is a native to Indonesian soil and it is a promising soybean nodule forming bacteria in Indonesia. Using indigenous bacteria is valuable. Since they are mostly more tolerant and adaptable than the introduced ones. An important aspect for the success of Biological Nitrogen Fixation (BNF) is insight in the structure of indigenous soybean rhizobia populations. Study on the biodiversity of soybean rhizobia was important conducted. (author)

Working Together: Strategies That Support Cross-Cultural Engagement of Indigenous Teacher Assistants Working in Indigenous Contexts

Science.gov (United States)

Armour, Danielle; Warren, Elizabeth; Miller, Jodie

2016-01-01

Indigenous teacher assistants (ITAs) are often employed in schools to assist in addressing educational issues relating to Indigenous students. While, this practice has occurred for over 40 years in most Australian states, little has been written about their contribution in assisting Indigenous students to learn. This paper explores the influence…

Plant Provocations: Botanical Indigeneity and (Decolonial Imaginations

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Narendran Kumarakulasingam

Full Text Available Abstract Abstract: This paper examines the possibilities and limitations of an emergent global discourse of indigeneity to offer an oppositional praxis in the face of the depredations of settler colonialism in post-apartheid South Africa. Self-conscious articulations of indigeneity, we argue, reveal the fraught relationship between increasingly hegemonic and narrow understandings of the indigenous and the carceral logic of apartheid. We examine this by focusing on the meanings and attachments forged through indigenous plants in two realms: the world of indigenous gardening practised by white suburban dwellers and that of subsistence farming undertaken by rural black women. This juxtaposition reveals that in contrast to the pervasive resurrection of colonial time that defines metropolitan indigenous gardening, the social relations of a subsistence cultivator challenge the confines of colonial temporality, revealing a creative mode of dissent structured around dreams, ancestral knowledge, and the commons. Our exploration of struggles around botanical indigeneity suggests that anticolonial modes of indigeneity do not necessarily inhere in recognisable forms and that studies of the indigenous need to proceed beyond those that bear familial resemblance to emergent global understandings.

Synergy between Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the Bioleaching Process of Copper

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Xuecheng Zheng

2016-01-01

Full Text Available This study investigates the synergy of Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the bioleaching process of copper. The results showed that additional R. phaseoli could increase leaching rate and cell number of A. ferrooxidans. When the initial cell number ratio between A. ferrooxidans and R. phaseoli was 2 : 1, A. ferrooxidans attained the highest final cell number of approximately 2 × 108 cells/mL and the highest copper leaching rate of 29%, which is 7% higher than that in the group with A. ferrooxidans only. R. phaseoli may use metabolized polysaccharides from A. ferrooxidans, and organic acids could chelate or precipitate harmful heavy metals to reduce their damage on A. ferrooxidans and promote its growth. Organic acids could also damage the mineral lattice to increase the leaching effect.

Synergy between Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the Bioleaching Process of Copper

Science.gov (United States)

Zheng, Xuecheng; Li, Dongwei

2016-01-01

This study investigates the synergy of Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the bioleaching process of copper. The results showed that additional R. phaseoli could increase leaching rate and cell number of A. ferrooxidans. When the initial cell number ratio between A. ferrooxidans and R. phaseoli was 2 : 1, A. ferrooxidans attained the highest final cell number of approximately 2 × 108 cells/mL and the highest copper leaching rate of 29%, which is 7% higher than that in the group with A. ferrooxidans only. R. phaseoli may use metabolized polysaccharides from A. ferrooxidans, and organic acids could chelate or precipitate harmful heavy metals to reduce their damage on A. ferrooxidans and promote its growth. Organic acids could also damage the mineral lattice to increase the leaching effect. PMID:26942203

Human papillomavirus prevalence among indigenous and non-indigenous Australian women prior to a national HPV vaccination program

Directory of Open Access Journals (Sweden)

Condon John R

2011-09-01

Full Text Available Abstract Background Indigenous women in Australia have a disproportionate burden of cervical cancer despite a national cervical screening program. Prior to introduction of a national human papilloma virus (HPV vaccination program, we determined HPV genotype prevalence by Indigenous status and residence in remote areas. Methods We recruited women aged 17 to 40 years presenting to community-based primary health services for routine Pap screening across Australia. A liquid-based cytology (LBC cervical specimen was tested for HPV DNA using the AMPLICOR HPV-DNA test and a PGMY09/11-based HPV consensus PCR; positive specimens were typed by reverse hybridization. We calculated age-adjusted prevalence by weighting to relevant population data, and determined predictors of HPV-DNA positivity by age, Indigenous status and area of residence using logistic regression. Results Of 2152 women (655 Indigenous, prevalence of the high-risk HPV genotypes was similar for Indigenous and non-Indigenous women (HPV 16 was 9.4% and 10.5%, respectively; HPV 18 was 4.1% and 3.8%, respectively, and did not differ by age group. In younger age groups, the prevalence of other genotypes also did not differ, but in those aged 31 to 40 years, HPV prevalence was higher for Indigenous women (35% versus 22.5%; P Conclusion Although we found no difference in the prevalence of HPV16/18 among Australian women by Indigenous status or, for Indigenous women, residence in remote regions, differences were found in the prevalence of risk factors and some other HPV genotypes. This reinforces the importance of cervical screening as a complement to vaccination for all women, and the value of baseline data on HPV genotype prevalence by Indigenous status and residence for the monitoring of vaccine impact.

Dadirri: Using a Philosophical Approach to Research to Build Trust between a Non-Indigenous Researcher and Indigenous Participants

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Megan Marie Stronach

2014-09-01

Full Text Available Abstract: This article focuses on a philosophical approach employed in a PhD research project that set out to investigate sport career transition (SCT experiences of elite Indigenous Australian sportsmen. The research was necessary as little is known about the transition of this cohort to a life after sport, or their experiences of retirement. A key problem within the SCT paradigm is a presumption that an end to elite sport requires a process of adjustment that is common to all sportspeople—a rather narrow perspective that fails to acknowledge the situational complexity and socio-cultural diversity of elite athletes. With such a range of personal circumstances, it is reasonable to suppose that athletes from different cultural groups will have different individual SCT needs. The researcher is non-Indigenous and mature aged: she encountered a number of challenges in her efforts to understand Indigenous culture and its important sensitivities, and to build trust with the Indigenous male participants she interviewed. An Indigenous philosophy known as Dadirri, which emphasises deep and respectful listening, guided the development of the research design and methodology. Consistent with previous studies conducted by non-Indigenous researchers, an open-ended and conversational approach to interviewing Indigenous respondents was developed. The objective was for the voices of the athletes to be heard, allowing the collection of rich data based on the participants’ perspectives about SCT. An overview of the findings is presented, illustrating that Indigenous athletes experience SCT in complex and distinctive ways. The article provides a model for non-Indigenous researchers to conduct qualitative research with Indigenous people.

Responding to Indigenous Australian Sexual Assault

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Janya McCalman

2014-01-01

Full Text Available Indigenous Australians experience a high prevalence of sexual assault, yet a regional sexual assault service found few Indigenous Australians accessed their services. This prompted exploration of how its services might be improved. A resultant systematic search of the literature is reported in this article. Seven electronic databases and seven websites were systematically searched for peer reviewed and gray literature documenting responses to the sexual assault of Indigenous Australians. These publications were then classified by response type and study type. Twenty-three publications met the inclusion criteria. They included studies of legal justice, media, and community-based and mainstream service responses for Indigenous survivors and perpetrators. We located program descriptions, measurement, and descriptive research, but no intervention studies. There is currently insufficient evidence to confidently prescribe what works to effectively respond to Indigenous Australian sexual assault. The study revealed an urgent need for researchers, Indigenous communities, and services to work together to develop the evidence base.

Leadership as a Personal Journey: An Indigenous Perspective.

Science.gov (United States)

Doyle, Kerrie; Hungerford, Catherine

2015-05-01

Indigenous Australians have higher levels of mental illness, self-harm, suicide and substance abuse than non-Indigenous Australians, as well as more frequent contact with the criminal justice system. These indices point to the need for strong leadership to support Close the Gap programmes that have now been implemented across Australia. This article considers leadership as a journey of learning for Australian Indigenous leaders. Through the use of story, it is suggested that a situational leadership approach, incorporating the principles of mindfulness, provides the most appropriate framework for Indigenous leaders who work with Indigenous communities. Flexible approaches are needed to meet the needs of diverse Indigenous populations, and address the complex challenges involved, including lateral violence. Such flexibility will enable Indigenous leaders and communities to work together to achieve improvements in the health outcomes, not only for Indigenous Australians, but also for Indigenous populations worldwide.

Indigenous healthcare worker involvement for Indigenous adults and children with asthma.

Science.gov (United States)

Chang, Anne B; Taylor, Brett; Masters, I Brent; Laifoo, Yancy; Brown, Alexander Dh

2010-05-12

Asthma education is regarded as an important step in the management of asthma in national guidelines. Racial, ethnicity and socio-economic factors are associated with markers of asthma severity, including recurrent acute presentations to emergency health facilities. Worldwide, indigenous groups are disproportionately represented in the severe end of the asthma spectrum. Appropriate models of care are important in the successful delivery of services, and are likely contributors to improved outcomes for people with asthma. To determine whether involvement of an indigenous healthcare worker (IHW) in comparison to absence of an IHW in asthma education programs, improves asthma related outcomes in indigenous children and adults with asthma. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE and EMBASE databases, review articles and reference lists of relevant articles. The latest search was in January 2010. All randomised controlled trials comparing involvement of an indigenous healthcare worker (IHW) in comparison to absence of an IHW in asthma education programs for indigenous people with asthma. Two independent review authors selected data for inclusion, a single author extracted the data. Both review authors independently assessed study quality. We contacted authors for further information. As it was not possible to analyse data as "intention-to-treat", we analysed data as "treatment received". Two studies fulfilled inclusion criteria involving 133 children randomised to an asthma education programme involving an IHW, compared to a similar education programme without an IHW. One study was not strictly Indigenous. 110 of these children completed the trials. Children's asthma knowledge score was significantly better in the group that had IHW education compared with control (mean difference 3.30; 95% CI 1.07 to 5.53), parents' asthma knowledge score (standardised mean difference (SMD) 1

Assessing the hydrocarbon degrading potential of indigenous bacteria isolated from crude oil tank bottom sludge and hydrocarbon-contaminated soil of Azzawiya oil refinery, Libya.

Science.gov (United States)

Mansur, Abdulatif A; Adetutu, Eric M; Kadali, Krishna K; Morrison, Paul D; Nurulita, Yuana; Ball, Andrew S

2014-09-01

The disposal of hazardous crude oil tank bottom sludge (COTBS) represents a significant waste management burden for South Mediterranean countries. Currently, the application of biological systems (bioremediation) for the treatment of COTBS is not widely practiced in these countries. Therefore, this study aims to develop the potential for bioremediation in this region through assessment of the abilities of indigenous hydrocarbonoclastic microorganisms from Libyan Hamada COTBS for the biotreatment of Libyan COTBS-contaminated environments. Bacteria were isolated from COTBS, COTBS-contaminated soil, treated COTBS-contaminated soil, and uncontaminated soil using Bushnell Hass medium amended with Hamada crude oil (1 %) as the main carbon source. Overall, 49 bacterial phenotypes were detected, and their individual abilities to degrade Hamada crude and selected COBTS fractions (naphthalene, phenanthrene, eicosane, octadecane and hexane) were evaluated using MT2 Biolog plates. Analyses using average well colour development showed that ~90 % of bacterial isolates were capable of utilizing representative aromatic fractions compared to 51 % utilization of representative aliphatics. Interestingly, more hydrocarbonoclastic isolates were obtained from treated contaminated soils (42.9 %) than from COTBS (26.5 %) or COTBS-contaminated (30.6 %) and control (0 %) soils. Hierarchical cluster analysis (HCA) separated the isolates into two clusters with microorganisms in cluster 2 being 1.7- to 5-fold better at hydrocarbon degradation than those in cluster 1. Cluster 2 isolates belonged to the putative hydrocarbon-degrading genera; Pseudomonas, Bacillus, Arthrobacter and Brevundimonas with 57 % of these isolates being obtained from treated COTBS-contaminated soil. Overall, this study demonstrates that the potential for PAH degradation exists for the bioremediation of Hamada COTBS-contaminated environments in Libya. This represents the first report on the isolation of

Alcaligenes is Commensal Bacteria Habituating in the Gut-Associated Lymphoid Tissue for the Regulation of Intestinal IgA Responses.

Science.gov (United States)

Kunisawa, Jun; Kiyono, Hiroshi

2012-01-01

Secretory-immunoglobulin A (S-IgA) plays an important role in immunological defense in the intestine. It has been known for a long time that microbial stimulation is required for the development and maintenance of intestinal IgA production. Recent advances in genomic technology have made it possible to detect uncultivable commensal bacteria in the intestine and identify key bacteria in the regulation of innate and acquired mucosal immune responses. In this review, we focus on the immunological function of Peyer's patches (PPs), a major gut-associated lymphoid tissue, in the induction of intestinal IgA responses and the unique immunological interaction of PPs with commensal bacteria, especially Alcaligenes, a unique indigenous bacteria habituating inside PPs.

Doing Climate Science in Indigenous Communities

Science.gov (United States)

Pandya, R. E.; Bennett, B.

2009-12-01

Historically, the goal of broadening participation in the geosciences has been expressed and approached from the viewpoint of the majority-dominated geoscience community. The need for more students who are American Indian, Native Hawaiian, or Alaska Native is expressed in terms of the need to diversify the research community, and strategies to engage more students are often posed around the question “what can we do to get more indigenous students interested in coming to our institutions to do geosciences?” This approach can lead to neglecting indigenous ways of knowing, inadvertently prioritizes western values over traditional ones, and doesn’t necessarily honor tribal community’s desire to hold on to their talented youth. Further, while this approach has resulted in some modest success, the overall participation in geoscience by students from indigenous backgrounds remains low. Many successful programs, however, have tried an alternate approach; they begin by approaching the geosciences from the viewpoint of indigenous communities. The questions they ask center around how geosciences can advance the priorities of indigenous communities, and their approaches focus on building capacity for the geosciences within indigenous communities. Most importantly, perhaps, these efforts originate in Tribal communities themselves, and invite the geoscience research community to partner in projects that are rooted in indigenous culture and values. Finally, these programs recognize that scientific expertise is only one among many skills indigenous peoples employ in their relation with their homelands. Climate change, like all things related to the landscape, is intimately connected to the core of indigenous cultures. Thus, emerging concerns about climate change provide a venue for developing new, indigenous-centered, approaches to the persistent problem of broadening participation in the geoscience. This presentation will highlight three indigenous-led efforts in to

The effect of lactic acid bacteria on cocoa bean fermentation.

Science.gov (United States)

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2015-07-16

Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

Non-Indigenous Women Teaching Indigenous Education: A Duoethnographic Exploration of Untold Stories

Science.gov (United States)

Burm, Sarah; Burleigh, Dawn

2017-01-01

Identifying as non-Indigenous, we are often left considering our positionality and identity in Indigenous education, how we have come to be invested in this area of research, and what we see as our contribution. In conversation with one another, we realized we choose to share certain stories and not others about our experiences working in…

Indigenous Rights in the Making: The United Nations Declaration on the Rights of Indigenous Peoples

OpenAIRE

Gilbert, Jérémie

2007-01-01

This article examines to what extent the recently adopted United Nations Declarations on the Rights of Indigenous Peoples participate to the development of indigenous peoples' international human rights.

Indigenous obesity in the news: a media analysis of news representation of obesity in Australia's Indigenous population.

Science.gov (United States)

Islam, Salwa; Fitzgerald, Lisa

2016-01-01

High rates of obesity are a significant issue amongst Indigenous populations in many countries around the world. Media framing of issues can play a critical role in shaping public opinion and government policy. A broad range of media analyses have been conducted on various aspects of obesity, however media representation of Indigenous obesity remains unexplored. In this study we investigate how obesity in Australia's Indigenous population is represented in newsprint media coverage. Media articles published between 2007 and 2014 were analysed for the distribution and extent of coverage over time and across Indigenous and mainstream media sources using quantitative content analysis. Representation of the causes and solutions of Indigenous obesity and framing in text and image content was examined using qualitative framing analysis. Media coverage of Indigenous obesity was very limited with no clear trends in reporting over time or across sources. The single Indigenous media source was the second largest contributor to the media discourse of this issue. Structural causes/origins were most often cited and individual solutions were comparatively overrepresented. A range of frames were employed across the media sources. All images reinforced textual framing except for one article where the image depicted individual factors whereas the text referred to structural determinants. This study provides a starting point for an important area of research that needs further investigation. The findings highlight the importance of alternative news media outlets, such as The Koori Mail, and that these should be developed to enhance the quality and diversity of media coverage. Media organisations can actively contribute to improving Indigenous health through raising awareness, evidence-based balanced reporting, and development of closer ties with Indigenous health workers.

Isolation and identification of indigenous prokaryotic bacteria from arsenic-contaminated water resources and their impact on arsenic transformation.

Science.gov (United States)

Jebelli, Mohammad Ahmadi; Maleki, Afshin; Amoozegar, Mohammad Ali; Kalantar, Enayatollah; Shahmoradi, Behzad; Gharibi, Fardin

2017-06-01

Arsenic is a known human carcinogen. Arsenite [As(III), H 3 AsO 3 ] and arsenate [As(V), H 2 AsO 4 - and HAsO 4 2- ] are the two predominant compounds of As found in surface water and groundwater. The aim of this study was to explore a bioremediation strategy for biotransformation of arsenite to arsenate by microorganisms. In this study, Babagorgor Spring, located west of Iran, was selected as the arsenic-contaminated source and its physicochemical characteristics and in situ microbiological composition were analyzed. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) analysis indicated that the arsenic level was 614μg/l. Fourteen arsenic tolerant indigenous bacteria were isolated from arsenic-contaminated water using chemically defined medium (CDM), supplemented with 260-3900mg/l arsenite and 1560-21800mg/l arsenate. Among the isolates, a strain As-11 exhibited high ability of arsenic transformation. Biochemical tests were used for bacterial identification and confirmation was conducted by 16S rRNA sequence analysis. Results confirmed that As-11 was related to the genus Pseudomonas. This bacterium showed maximum tolerable concentration to arsenite up to 3250mg/l and arsenate up to 20280mg/l. Under heterotrophic conditions, the bacterium exhibited 48% of As(III) and 78% of As(V) transformation from the medium amended with 130 and 312mg/l of sodium arsenite and sodium arsenate, respectively. Moreover, under chemolithotrophic conditions, bacterium was able to transform 41% of 130mg/l of As(III) from the medium amended with nitrate as the terminal electron acceptor. Pseudomonas strain As-11 was reported as an arsenic transformer, for the first time. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of bioleaching column test of sulphide copper ore and copper concentrate using preconditioned surface

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Videla Leiva Alvaro

2016-01-01

Full Text Available Bacterial activity can be related to the presence of Fe+3 in the solution, which drives copper oxidation during the secondary copper low grade sulfide ore leaching process. The present work evaluates improvements in kinetics of leaching when ferroxidans are preconditioned in an inert surface helping to build a biofilm which improves metabolism of the colony. The present work shows evaluation using laboratory columns to perform bioleaching during a 30 days period under three conditions: a base column with no inert surface, a column with loofa available for bacterial growth and conditioning, and finally a column with the loofa surface ground and distributed in the column among the particles.

Geographic distribution of isolated indigenous societies in Amazonia and the efficacy of indigenous territories.

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Kesler, Dylan C; Walker, Robert S

2015-01-01

The headwaters of the Amazon Basin harbor most of the world's last indigenous peoples who have limited contact with encroaching colonists. Knowledge of the geographic distribution of these isolated groups is essential to assist with the development of immediate protections for vulnerable indigenous settlements. We used remote sensing to document the locations of 28 isolated villages within the four Brazilian states of Acre, Amazonas, Roraima, and Rondônia. The sites were confirmed during previous over-flights and by image evidence of thatched-roof houses; they are estimated to host over 1,700 individuals. Locational data were used to train maximum entropy models that identified landscape and anthropogenic features associated with the occurrence of isolated indigenous villages, including elevation, proximity to streams of five different orders, proximity to roads and settlements, proximity to recent deforestation, and vegetation cover type. Isolated villages were identified at mid elevations, within 20 km of the tops of watersheds and at greater distances from existing roads and trails. We further used model results, combined with boundaries of the existing indigenous territory system that is designed to protect indigenous lands, to assess the efficacy of the existing protected area network for isolated peoples. Results indicate that existing indigenous territories encompass all of the villages we identified, and 50% of the areas with high predicted probabilities of isolated village occurrence. Our results are intended to help inform policies that can mitigate against future external threats to isolated peoples.

Geographic distribution of isolated indigenous societies in Amazonia and the efficacy of indigenous territories.

Directory of Open Access Journals (Sweden)

Dylan C Kesler

Full Text Available The headwaters of the Amazon Basin harbor most of the world's last indigenous peoples who have limited contact with encroaching colonists. Knowledge of the geographic distribution of these isolated groups is essential to assist with the development of immediate protections for vulnerable indigenous settlements. We used remote sensing to document the locations of 28 isolated villages within the four Brazilian states of Acre, Amazonas, Roraima, and Rondônia. The sites were confirmed during previous over-flights and by image evidence of thatched-roof houses; they are estimated to host over 1,700 individuals. Locational data were used to train maximum entropy models that identified landscape and anthropogenic features associated with the occurrence of isolated indigenous villages, including elevation, proximity to streams of five different orders, proximity to roads and settlements, proximity to recent deforestation, and vegetation cover type. Isolated villages were identified at mid elevations, within 20 km of the tops of watersheds and at greater distances from existing roads and trails. We further used model results, combined with boundaries of the existing indigenous territory system that is designed to protect indigenous lands, to assess the efficacy of the existing protected area network for isolated peoples. Results indicate that existing indigenous territories encompass all of the villages we identified, and 50% of the areas with high predicted probabilities of isolated village occurrence. Our results are intended to help inform policies that can mitigate against future external threats to isolated peoples.

Genetic and Environmental Determinants of Otitis Media in an Indigenous Filipino Population.

Science.gov (United States)

Santos-Cortez, Regie Lyn P; Reyes-Quintos, Ma Rina T; Tantoco, Ma Leah C; Abbe, Izoduwa; Llanes, Erasmo Gonzalo D V; Ajami, Nadim J; Hutchinson, Diane S; Petrosino, Joseph F; Padilla, Carmencita D; Villarta, Romeo L; Gloria-Cruz, Teresa Luisa; Chan, Abner L; Cutiongco-de la Paz, Eva Maria; Chiong, Charlotte M; Leal, Suzanne M; Abes, Generoso T

2016-11-01

To identify genetic and environmental risk factors for otitis media in an indigenous Filipino population. Cross-sectional study. Indigenous Filipino community. Clinical history and information on breastfeeding, tobacco smoke exposure, and swimming were obtained from community members. Heads of households were interviewed for family history and personal beliefs on ear health. Height and weight were measured. Otoscopic findings were described for the presence and character of perforation or discharge. An A2ML1 duplication variant that confers otitis media susceptibility was Sanger sequenced in all DNA samples. Co-occurrence of middle ear bacteria detected by 16S rRNA gene sequencing was determined according to A2ML1 genotype and social cluster. The indigenous Filipino population has a ~50% prevalence of otitis media. Young age was associated with otitis media (4 age strata; P = .004); however, age was nonsignificant as a bistratal or continuous variable. There was no association between otitis media and sex, body mass index, breastfeeding, tobacco exposure, or deep swimming. In multivariate analyses, A2ML1 genotype is the strongest predictor of otitis media, with an odds ratio of 3.7 (95% confidence interval: 1.3-10.8; P = .005). When otitis media diagnoses were plotted across ages, otitis media was observed within the first year of life, and chronic otitis media persisted up to adulthood, particularly in A2ML1-variant carriers. Among indigenous Filipinos, A2ML1 genotype is the primary risk factor for otitis media and main determinant of disease progression, although age, the middle ear microbiome, and social clusters might modulate the effect of the A2ML1 genotype. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

CONTEMPORARY INDIGENOUS LITERATURE: FORMS AND CONTENTS IN THE POETRY AND PROSE OF THE II LITERARY PARTY OF INDIGENOUS POETICS.

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Deborah Goldemberg

2010-06-01

Full Text Available By analyzing the forms and contents of the presentations made by indigenous performers and writers at the I Literary Party of Indigenous Poetics, this article exposes the challenges faced by traditional genre theories in tackling indigenous narratives and analyses how this “crisis” contributes to widening hierarchical and Western biased conceptions. On a stage open to contemporary indigenous expression, as is the literary party, the concepts of performance and storytelling, with the social function of maintaining tradition, continuous learning and transformation, better define this indigenous expression.

Growth characteristics of a strain of iron-oxidizing bacterium and its application in bioleaching of uranium ores

International Nuclear Information System (INIS)

Zhang Rui; Liu Yajie; Gao Feng; Xu Lingling

2008-01-01

05B is a strain of iron-oxidizing bacterium which separated from a uranium ore. The effect of temperature, initial pH, inoculation amount and initial total iron concentration on the strain's growth and activities in bioleaching of uranium ores are studied. The results show that the optimum growth temperature is 40-45 degree C, the optimum inoculation pH value being 1.5-1.7, the optimum initial inoculation amount being 10%-20%, and the initial total iron concentration being not more than 5 g/L. 05B is fit for leaching of low grade uranium ores. (authors)

Bio-extraction of precious metals from urban solid waste

Science.gov (United States)

Das, Subhabrata; Natarajan, Gayathri; Ting, Yen-Peng

2017-01-01

Reduced product lifecycle and increasing demand for electronic devices have resulted in the generation of huge volumes of electronic waste (e-waste). E-wastes contain high concentrations of toxic heavy metals, which have detrimental effects on health and the environment. However, e-wastes also contain significant concentrations of precious metals such as gold, silver and palladium, which can be a major driving force for recycling of urban waste. Cyanogenic bacteria such as Chromobacterium violaceum generate cyanide as a secondary metabolite which mobilizes gold into solution via a soluble gold-cyanide complex. However, compared to conventional technology for metal recovery, this approach is not effective, owing largely to the low concentration of lixiviants produced by the bacteria. To overcome the challenges of bioleaching of gold from e-waste, several strategies were adopted to enhance gold recovery rates. These included (i) pretreatment of e-waste to remove competing metal ions, (ii) mutation to adapt the bacteria to high pH environment, (iii) metabolic engineering to produce higher cyanide lixiviant, and (iv) spent medium leaching with adjusted initial pH. Compared to 7.1 % recovery by the wild type bacteria, these strategies achieved gold recoveries of 11.3%, 22.5%, 30% and 30% respectively at 0.5% w/v pulp density respectively. Bioleached gold was finally mineralized and precipitated as gold nanoparticles using the bacterium Delftia acidovorans. This study demonstrates the potential for enhancement of biocyanide production and gold recovery from electronic waste through different strategies, and extraction of solid gold from bioleached leachate.

Metal recovery via geobiotechnology

International Nuclear Information System (INIS)

Hedrich, Sabrina; Schippers, Axel

2017-01-01

Specialized acidophilic bacteria and archaea are able to extract valuable metals such as copper, gold, cobalt, nickel, zinc, and uranium from sulfide ores. This process is known as bioleaching and its application in the mining industry as biomining. Laboratory studies also demonstrated bioleaching of oxide ores such as laterites and of mining residues such as mine tailings as well as metal recycling from waste (secondary mining). Metals being leached have to be recovered from acidic polymetallic solutions (mine and process waters) which is possible via biosorption or biomineralisation.

Metal recovery via geobiotechnology; Metallgewinnung mittels Geobiotechnologie

Energy Technology Data Exchange (ETDEWEB)

Hedrich, Sabrina; Schippers, Axel [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany). Fachbereich Geochemie der Rohstoffe

2017-02-15

Specialized acidophilic bacteria and archaea are able to extract valuable metals such as copper, gold, cobalt, nickel, zinc, and uranium from sulfide ores. This process is known as bioleaching and its application in the mining industry as biomining. Laboratory studies also demonstrated bioleaching of oxide ores such as laterites and of mining residues such as mine tailings as well as metal recycling from waste (secondary mining). Metals being leached have to be recovered from acidic polymetallic solutions (mine and process waters) which is possible via biosorption or biomineralisation.

Population dynamics of the fast-growing sub-populations of Pseudomonas and total bacteria, and their protozoan grazers, revealed by fenpropimorph treatment

DEFF Research Database (Denmark)

Thirup, L; Ekelund, Flemming; Johnsen, Kaare Eske

2000-01-01

The population dynamics of indigenous soil bacteria and protozoa on decaying barley roots were followed by using litter bags buried in laboratory-incubated soil. The soil was either non-treated or treated with the fungicide fenpropimorph (in the formulation Corbel) at concentrations corresponding...... of protozoa corresponding to the two subpopulations was followed. The results strongly indicate a predatory association between the protozoa and bacteria. This was shown by a tight temporal association, and by a stimulation of bacteria following predatory release when protozoa were inhibited by fenpropimorph...

Socioeconomic status and self-reported asthma in Indigenous and non-Indigenous Australian adults aged 18-64 years: analysis of national survey data

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Cunningham Joan

2010-08-01

Full Text Available Abstract Background Asthma is more common among Indigenous than non-Indigenous Australian adults, but little is known about socioeconomic patterning of asthma within the Indigenous population, or whether it is similar to the non-Indigenous population. Methods I analysed weighted data on self-reported current diagnosed asthma and a range of socio-economic and demographic measures for 5,417 Indigenous and 15,432 non-Indigenous adults aged 18-64 years from two nationally representative surveys conducted in parallel by the Australian Bureau of Statistics in 2004-05. Results Current asthma prevalence was higher for Indigenous than non-Indigenous people in every age group. After adjusting for age and sex, main language and place of residence were significantly associated with asthma prevalence in both populations. Traditional SES variables such as education, income and employment status were significantly associated with asthma in the non-Indigenous but not the Indigenous population. For example, age-and sex-adjusted relative odds of asthma among those who did not complete Year 10 (versus those who did was 1.2 (95% confidence interval (CI 1.0-1.5 in the non-Indigenous population versus 1.0 (95% CI 0.8-1.3 in the Indigenous population. Conclusions The socioeconomic patterning of asthma among Indigenous Australians is much less pronounced than for other chronic diseases such as diabetes and kidney disease, and contrasts with asthma patterns in the non-Indigenous population. This may be due in part to the episodic nature of asthma, and the well-known challenges in diagnosing it, especially among people with limited health literacy and/or limited access to health care, both of which are more likely in the Indigenous population. It may also reflect the importance of exposures occurring across the socioeconomic spectrum among Indigenous Australians, such as racism, and discrimination, marginalization and dispossession, chronic stress and exposure to

Suicidal behaviour in Indigenous compared to non-Indigenous males in urban and regional Australia: Prevalence data suggest disparities increase across age groups.

Science.gov (United States)

Armstrong, Gregory; Pirkis, Jane; Arabena, Kerry; Currier, Dianne; Spittal, Matthew J; Jorm, Anthony F

2017-12-01

We compare the prevalence of suicidal thoughts and attempts between Indigenous and non-Indigenous males in urban and regional Australia, and examine the extent to which any disparity between Indigenous and non-Indigenous males varies across age groups. We used data from the baseline wave of The Australian Longitudinal Study on Male Health (Ten to Men), a large-scale cohort study of Australian males aged 10-55 years residing in urban and regional areas. Indigenous identification was determined through participants self-reporting as Aboriginal, Torres Strait Islander or both. The survey collected data on suicidal thoughts in the preceding 2 weeks and lifetime suicide attempts. A total of 432 participants (2.7%) identified as Indigenous and 15,425 as non-Indigenous (97.3%). Indigenous males were twice as likely as non-Indigenous males to report recent suicidal thoughts (17.6% vs 9.4%; odds ratio = 2.1, p age groups, but a significant gap emerged among men aged 30-39 years and was largest among men aged 40-55 years. Similarly, the prevalence of lifetime suicide attempts did not differ between Indigenous and non-Indigenous males in the 14- to 17-years age group, but a disparity emerged in the 18- to 24-years age group and was even larger among males aged 25 years and older. Our paper presents unique data on suicidal thoughts and attempts among a broad age range of Indigenous and non-Indigenous males. The disparity in the prevalence of suicidal thoughts increased across age groups, which is in contrast to the large disparity between the Indigenous and non-Indigenous suicide rates in younger age groups.

Population dynamics of mixed cultures of yeast and lactic acid bacteria in cider conditions

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Leila Roseli Dierings

2013-10-01

Full Text Available The objective of this work was to study the malolactic bioconversion in low acidity cider, according Brazilian conditions. The apple must was inoculated with Saccharomyces cerevisiae or S. cerevisiae with Oenococcus oeni. The control contained the indigenous microorganisms. Fermentation assays were carried out with clarified apple must from the Gala variety. At the beginning of fermentation, there was a fast growth of the non-Saccharomyces yeast population. Competitive inhibition occurred in all the assays, either with inoculated or indigenous populations of the yeast. The lactic acid bacteria count was ca. 1.41·10²CFU/mL at the beginning and 10(6CFU/mL after yeast cells autolysis. The lactic bacteria O. oeni reached the highest population (10(7CFU/mL when added to the apple must after the decline of the yeast. The malic acid was totally consumed during the alcoholic fermentation period (80.0 to 95.5 % and lactic acid was still synthesized during the 35 days of malolactic fermentation. These results could be important in order to achieve a high quality brut, or sec cider obtained from the dessert apple must.

FCJ-209 Indigenous Knowledge Systems and Pattern Thinking: An Expanded Analysis of the First Indigenous Robotics Prototype Workshop

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Angie Abdilla

2016-12-01

Full Text Available In November 2014, the lead researcher’s interest in the conceptual development of digital technology and her cultural connection to Indigenous Knowledge Systems created an opportunity to explore a culturally relevant use of technology with urban Indigenous youth: the Indigenous Robotics Prototype Workshop. The workshop achieved a sense of cultural pride and confidence in Indigenous traditional knowledge while inspiring the youth to continue with their engagement in coding and programming through building robots. Yet, the outcomes from the prototype workshop further revealed a need to investigate how Indigenous Knowledge Systems, and particularly Pattern Thinking, might hint toward a possible paradigm shift for the ethical and advanced design of new technologies. This article examines the implications of such a hypothetical shift in autonomous systems in robotics and artificial intelligence (AI, using the Indigenous Robotics Prototype Workshop as a case study and springboard.

Sporting Chance: Indigenous Participation in Australian Sport History

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Sean Gorman

2010-08-01

Full Text Available For many non-Indigenous Australians the only time they have any engagement with Indigenous peoples, history or issues is through watching sport on television or being at a football match at the MCG. This general myopia and indifference by settler Australians with Indigenous Australians manifests itself in many ways but perhaps most obscenely in the simple fact that Indigenous Australians die nearly 20 years younger than the rest of Australias citizens. Many non-Indigenous Australians do not know this. Sport in many ways has offered Indigenous Australians a platform from which to begin the slow, hard process for social justice and equity to be actualised. This paper will discuss the participation of Indigenous Australians in sport and show how sport has enabled Indigenous Australians to create a space so that they can speak out against the injustices they have experienced and to further improve on relations going into the future. The central contention is that through sport all Australians can begin a process of engaging with Indigenous history as a means to improve race relations between the two groups.

Preliminary exploration and thought of promoting library science Indigenization

International Nuclear Information System (INIS)

Liu Wenping; Du Jingling

2014-01-01

The article explains the significance of Library Science Indigenization, Answer some misunderstanding of Library Science Indigenization,reveals express form of Library Science Indigenization, Discusses criteria of Library Science Indigenization, finally give some suggestions and methods of Library Science Indigenization. (authors)

Comorbidity and cervical cancer survival of Indigenous and non-Indigenous Australian women: A semi-national registry-based cohort study (2003-2012).

Science.gov (United States)

Diaz, Abbey; Baade, Peter D; Valery, Patricia C; Whop, Lisa J; Moore, Suzanne P; Cunningham, Joan; Garvey, Gail; Brotherton, Julia M L; O'Connell, Dianne L; Canfell, Karen; Sarfati, Diana; Roder, David; Buckley, Elizabeth; Condon, John R

2018-01-01

Little is known about the impact of comorbidity on cervical cancer survival in Australian women, including whether Indigenous women's higher prevalence of comorbidity contributes to their lower survival compared to non-Indigenous women. Data for cervical cancers diagnosed in 2003-2012 were extracted from six Australian state-based cancer registries and linked to hospital inpatient records to identify comorbidity diagnoses. Five-year cause-specific and all-cause survival probabilities were estimated using the Kaplan-Meier method. Flexible parametric models were used to estimate excess cause-specific mortality by Charlson comorbidity index score (0,1,2+), for Indigenous women compared to non-Indigenous women. Of 4,467 women, Indigenous women (4.4%) compared to non-Indigenous women had more comorbidity at diagnosis (score ≥1: 24.2% vs. 10.0%) and lower five-year cause-specific survival (60.2% vs. 76.6%). Comorbidity was associated with increased cervical cancer mortality for non-Indigenous women, but there was no evidence of such a relationship for Indigenous women. There was an 18% reduction in the Indigenous: non-Indigenous hazard ratio (excess mortality) when comorbidity was included in the model, yet this reduction was not statistically significant. The excess mortality for Indigenous women was only evident among those without comorbidity (Indigenous: non-Indigenous HR 2.5, 95%CI 1.9-3.4), indicating that factors other than those measured in this study are contributing to the differential. In a subgroup of New South Wales women, comorbidity was associated with advanced-stage cancer, which in turn was associated with elevated cervical cancer mortality. Survival was lowest for women with comorbidity. However, there wasn't a clear comorbidity-survival gradient for Indigenous women. Further investigation of potential drivers of the cervical cancer survival differentials is warranted. The results highlight the need for cancer care guidelines and multidisciplinary

Comorbidity and cervical cancer survival of Indigenous and non-Indigenous Australian women: A semi-national registry-based cohort study (2003-2012.

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Abbey Diaz

Full Text Available Little is known about the impact of comorbidity on cervical cancer survival in Australian women, including whether Indigenous women's higher prevalence of comorbidity contributes to their lower survival compared to non-Indigenous women.Data for cervical cancers diagnosed in 2003-2012 were extracted from six Australian state-based cancer registries and linked to hospital inpatient records to identify comorbidity diagnoses. Five-year cause-specific and all-cause survival probabilities were estimated using the Kaplan-Meier method. Flexible parametric models were used to estimate excess cause-specific mortality by Charlson comorbidity index score (0,1,2+, for Indigenous women compared to non-Indigenous women.Of 4,467 women, Indigenous women (4.4% compared to non-Indigenous women had more comorbidity at diagnosis (score ≥1: 24.2% vs. 10.0% and lower five-year cause-specific survival (60.2% vs. 76.6%. Comorbidity was associated with increased cervical cancer mortality for non-Indigenous women, but there was no evidence of such a relationship for Indigenous women. There was an 18% reduction in the Indigenous: non-Indigenous hazard ratio (excess mortality when comorbidity was included in the model, yet this reduction was not statistically significant. The excess mortality for Indigenous women was only evident among those without comorbidity (Indigenous: non-Indigenous HR 2.5, 95%CI 1.9-3.4, indicating that factors other than those measured in this study are contributing to the differential. In a subgroup of New South Wales women, comorbidity was associated with advanced-stage cancer, which in turn was associated with elevated cervical cancer mortality.Survival was lowest for women with comorbidity. However, there wasn't a clear comorbidity-survival gradient for Indigenous women. Further investigation of potential drivers of the cervical cancer survival differentials is warranted.The results highlight the need for cancer care guidelines and

Injury prevention in Australian Indigenous communities.

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Ivers, Rebecca; Clapham, Kathleen; Senserrick, Teresa; Lyford, Marilyn; Stevenson, Mark

2008-12-01

Injury prevention in Indigenous communities in Australia is a continuing national challenge, with Indigenous fatality rates due to injury three times higher than the general population. Suicide and transport are the leading causes of injury mortality, and assault, transport and falls the primary causes of injury morbidity. Addressing the complex range of injury problems in disadvantaged Indigenous communities requires considerable work in building or enhancing existing capacity of communities to address local safety issues. Poor data, lack of funding and absence of targeted programs are some of the issues that impede injury prevention activities. Traditional approaches to injury prevention can be used to highlight key areas of need, however adaptations are needed in keeping with Indigenous peoples' holistic approach to health, linked to land and linked to community in order to address the complex spiritual, emotional and social determinants of Indigenous injury.

Tuberculosis in indigenous children in the Brazilian Amazon

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Caroline Gava

2013-02-01

Full Text Available OBJECTIVE: Assess the epidemiological aspects of tuberculosis in Brazilian indigenous children and actions to control it. METHODS: An epidemiological study was performed with 356 children from 0 to 14 years of age in Rondônia State, Amazon, Brazil, during the period 1997-2006. Cases of TB reported to the Notifiable Diseases Surveillance System were divided into indigenous and non-indigenous categories and analyzed according to sex, age group, place of residence, clinical form, diagnostic tests and treatment outcome. A descriptive analysis of cases and hypothesis test (χ² was carried out to verify if there were differences in the proportions of illness between the groups investigated. RESULTS: A total of 356 TB cases were identified (125 indigenous, 231 non-indigenous of which 51.4% of the cases were in males. In the indigenous group, 60.8% of the cases presented in children aged 0-4 years old. The incidence mean was much higher among indigenous; in 2001, 1,047.9 cases/100,000 inhabitants were reported in children aged < 5 years. Pulmonary TB was reported in more than 80% of the cases, and in both groups over 70% of the cases were cured. Cultures and histopathological exams were performed on only 10% of the patients. There were 3 cases of TB/HIV co-infection in the non-indigenous group and none in the indigenous group. The case detection rate was classified as insufficient or fair in more than 80% of the indigenous population notifications, revealing that most of the diagnoses were performed based on chest x-ray. CONCLUSIONS: The approach used in this study proved useful in demonstrating inequalities in health between indigenous and non-indigenous populations and was superior to the conventional analyses performed by the surveillance services, drawing attention to the need to improve childhood TB diagnosis among the indigenous population.

Contrasting colonist and indigenous impacts on amazonian forests.

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Lu, Flora; Gray, Clark; Bilsborrow, Richard E; Mena, Carlos F; Erlien, Christine M; Bremner, Jason; Barbieri, Alisson; Walsh, Stephen J

2010-06-01

To examine differences in land use and environmental impacts between colonist and indigenous populations in the northern Ecuadorian Amazon, we combined data from household surveys and remotely sensed imagery that was collected from 778 colonist households in 64 colonization sectors, and 499 households from five indigenous groups in 36 communities. Overall, measures of deforestation and forest fragmentation were significantly greater for colonists than indigenous peoples. On average, colonist households had approximately double the area in agriculture and cash crops and 5.5 times the area in pasture as indigenous households. Nevertheless, substantial variation in land-use patterns existed among the five indigenous groups in measures such as cattle ownership and use of hired agricultural labor. These findings support the potential conservation value of indigenous lands while cautioning against uniform policies that homogenize indigenous ethnic groups.

Indigenous Australians and Preschool Education: Who Is Attending?

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Biddle, Nicholas

2007-01-01

This paper discusses the individual, family, household and area level characteristics associated with preschool attendance for Indigenous and non-Indigenous Australians (aged three to five years who are not at school). Controlling for these factors explains all of the difference between Indigenous and non-Indigenous attendance rates for…

Indigenous Elementary Students' Science Instruction in Taiwan: Indigenous Knowledge and Western Science

Science.gov (United States)

Lee, Huei; Yen, Chiung-Fen; Aikenhead, Glen S.

2012-12-01

This preliminary ethnographic investigation focused on how Indigenous traditional wisdom can be incorporated into school science and what students learned as a result. Participants included community elders and knowledge keepers, as well as 4th grade (10-year-old) students, all of Amis ancestry, an Indigenous tribe in Taiwan. The students' non-Indigenous teacher played a central role in developing a science module `Measuring Time' that combined Amis knowledge and Western science knowledge. The study identified two cultural worldview perspectives on time; for example, the place-based cyclical time held by the Amis, and the universal rectilinear time presupposed by scientists. Students' pre-instructional fragmented concepts from both knowledge systems became more informed and refined through their engagement in `Measuring Time'. Students' increased interest and pride in their Amis culture were noted.

Drug Policy and Indigenous Peoples.

Science.gov (United States)

Burger, Julian; Kapron, Mary

2017-06-01

This paper identifies the principal concerns of indigenous peoples with regard to current international treaties on certain psychoactive substances and policies to control and eradicate their production, trafficking, and sale. Indigenous peoples have a specific interest in the issue since their traditional lands have become integrated over time into the large-scale production of coca, opium poppy, and cannabis crops, in response to high demand from the American and European markets, among others. As a consequence, indigenous peoples are persecuted because of their traditional use of these and other plant-based narcotics and hallucinogens. They are also victims of the drug producers who remove them from their lands or forcibly recruit them into the production process. As indigenous peoples are caught in the violent world of illicit drug production, law enforcement often targets them first, resulting in disproportionate rates of criminalization and incarceration.

The Mapuche People's Battle for Indigenous Land. Litigation as a Strategy to Defend Indigenous Land Rights

OpenAIRE

Skjævestad, Anne

2008-01-01

Land is the foundation for the economic sustenance of indigenous peoples and for the continued survival of their cultures. One of the major problems faced by indigenous peoples is the dispossession of their traditional lands and territories. The activities of business interests and economic development projects in indigenous territories – such as forest logging and infrastructure projects - and the environmental implications of such activities, often constitute a great threat to the livelihoo...

Revolutionizing Environmental Education through Indigenous Hip Hop Culture

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Gorlewski, Julie; Porfilio, Brad J.

2012-01-01

Based upon the life histories of six Indigenous hip hop artists of the Beat Nation artist collective, this essay captures how Indigenous hip hop has the potential to revolutionize environmental education. Hip hop provides Indigenous youth an emancipatory space to raise their opposition to neocolonial controls of Indigenous territories that…

INDIGENOUS LANGUAGES & PORTUGUESE LANGUAGE IN INDIGENOUS COMMUNITIES IN THE SOUTHERN OF MATO GROSSO DO SUL

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Marilze Tavares

2016-12-01

Full Text Available Most part of indigenous adults in the Guarani communities of Mato Grosso do Sul is bilingual and has one of the indigenous languages, Guarani Kaiowá or Guarani Ñandeva, as their mother tongue and Portuguese as a second language; only a few elderly and young children still who do not go to school speak only the mother tongue. In this paper, we try to verify which impression the speakers have for each of these languages and the importance they attribute to each one of them. Data analysis showed that the mother tongue is closely related to the expression of their traditional culture; in general, the indigenous claim their languages are being transmitted to new generations, and therefore preserved in an appropriate manner in the two communities. The Portuguese is also considered very important by all informants and the main motivation for its teaching/learning is the need to contact with the non-indigenous population. These results may help us understand issues related to the future of these indigenous languages and Portuguese language in the investigated communities.

Hospital Utilisation in Indigenous and Non-Indigenous Infants under 12 Months of Age in Western Australia, Prospective Population Based Data Linkage Study.

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Kimberley McAuley

Full Text Available Indigenous infants (infants aged under 12 months have the highest hospital admission and emergency department presentation risks in Australia. However, there have been no recent reports comparing hospital utilisation between Indigenous and non-Indigenous infants.Our primary objective was to use a large prospective population-based linked dataset to assess the risk of all-cause hospital admission and emergency department presentation in Indigenous compared to non-Indigenous infants in Western Australia (WA. Secondary objectives were to assess the effect of socio-economic status (Index of Relative Socio-Economic Disadvantage [IRSD] on hospital utilisation and to understand the causes of hospital utilisation.There were 3,382 (5.4% Indigenous and 59,583 (94.6% non-Indigenous live births in WA from 1 January 2010 to 31 December 2011. Indigenous infants had a greater risk of hospital admission (adjusted odds ratio [aOR] 1.90, 95% confidence interval [95% CI] 1.77-2.04, p = <0.001 and emergency department presentation (aOR 2.15, 95% CI 1.98-2.33, p = <0.001 compared to non-Indigenous infants. Fifty nine percent (59.0% of admissions in Indigenous children were classified as preventable compared to 31.2% of admissions in non-Indigenous infants (aOR 2.12, 95% CI 1.88-2.39. The risk of hospital admission in the most disadvantaged (IRSD 1 infants in the total cohort (35.7% was similar to the risk in the least disadvantaged (IRSD 5 infants (30.6% (aOR 1.04, 95% CI 0.96-1.13, p = 0.356.WA Indigenous infants have much higher hospital utilisation than non Indigenous infants. WA health services should prioritise Indigenous infants regardless of their socio economic status or where they live.

Association of bacteria with marine invertebrates: Implications for ballast water management

Digital Repository Service at National Institute of Oceanography (India)

Khandeparker, L.; Anil, A.C.

stream_size 36739 stream_content_type text/plain stream_name EcoHealth_10_268a.pdf.txt stream_source_info EcoHealth_10_268a.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 1 Author version: EcoHealth... transportation, can have direct impact on society and human health. Ship’s ballast tanks hold different non-indigenous vertebrates, invertebrates, plants, microscopic algae, bacteria etc. (Williams et al. 1988; Carlton and Geller 1993; Smith et al. 1996...

Reduced nephron endowment in the neonates of Indigenous Australian peoples.

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Kandasamy, Y; Smith, R; Wright, I M R; Lumbers, E R

2014-02-01

Rates of chronic kidney disease (CKD) among Indigenous groups in Australia exceed non-Indigenous rates eight-fold. Using kidney volume as a surrogate for nephron number, we carried out a study to determine if Indigenous neonates have a smaller kidney volume (and thus a reduced nephron number) from birth compared with non-Indigenous neonates. We recruited term and preterm neonates (Indigenous) and 39 term (13 Indigenous) neonates. TKV of Indigenous neonates was significantly lower at 32 weeks [12.0 (2.0) v. 15.4 (5.1) ml; P=0.03] and 38 weeks CA [18.6 (4.0) v. 22.6 (5.9) ml; P=0.04] respectively. Term Indigenous neonates also had smaller kidney volumes compared with non-Indigenous neonates. Despite a smaller kidney volume (and reduced nephron number), Indigenous neonates did not have a significantly lower eGFR. Indigenous neonates achieve similar eGFRs to Non-Indigenous neonates, presumably through a higher single nephron filtration rate. This places Indigenous neonates at a greater risk of long-term kidney damage later in life.

Functional and probiotic attributes of an indigenous isolate of Lactobacillus plantarum.

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Jai K Kaushik

Full Text Available BACKGROUND: Probiotic microorganisms favorably alter the intestinal microflora balance, promote intestinal integrity and mobility, inhibit the growth of harmful bacteria and increase resistance to infection. Probiotics are increasingly used in nutraceuticals, functional foods or in microbial interference treatment. However, the effectiveness of probiotic organism is considered to be population-specific due to variation in gut microflora, food habits and specific host-microbial interactions. Most of the probiotic strains available in the market are of western or European origin, and a strong need for exploring new indigenous probiotic organisms is felt. METHODS AND FINDINGS: An indigenous isolate Lp9 identified as Lactobacillus plantarum by molecular-typing methods was studied extensively for its functional and probiotic attributes, viz., acid and bile salt tolerance, cell surface hydrophobicity, autoaggregation and Caco-2 cell-binding as well as antibacterial and antioxidative activities. Lp9 isolate could survive 2 h incubation at pH 1.5-2.0 and toxicity of 1.5-2.0% oxgall bile. Lp9 could deconjugate major bile salts like glycocholate and deoxytaurocholate, indicating its potential to cause hypocholesterolemia. The isolate exhibited cell-surface hydrophobicity of approximately 37% and autoaggregation of approximately 31%. Presence of putative probiotic marker genes like mucus-binding protein (mub, fibronectin-binding protein (fbp and bile salt hydrolase (bsh were confirmed by PCR. Presence of these genes suggested the possibility of specific interaction and colonization potential of Lp9 isolate in the gut, which was also suggested by a good adhesion ratio of 7.4+/-1.3% with Caco-2 cell line. The isolate demonstrated higher free radical scavenging activity than standard probiotics L. johnsonii LA1 and L. acidophilus LA7. Lp9 also exhibited antibacterial activity against E. coli, L. monocytogenes, S. typhi, S. aureus and B. cereus. CONCLUSION

Spatial distribution of tuberculosis in indigenous and non-indigenous populations in the state of Pará, Brazil, 2005-2013

OpenAIRE

Paiva, Bárbara Lopes; Azeredo, Jéssica Quelé; Nogueira, Laura Maria Vidal; Santos, Bruno de Oliveira; Rodrigues, Ivaneide Leal Ataide; Santos, Marcandra Nogueira de Almeida

2017-01-01

Abstract Objective: To analyze the incidence of tuberculosis in indigenous and non-indigenous residents in the state of Pará from 2005-2013. Method: An ecological study was performed with data from SINAN, stratified for the 13 existing Regional Health Centers in Pará. The tuberculosis incidence rates were calculated for indigenous and non-indigenous populations in the 13 regions and maps were prepared to visualize the magnitude of the occurrence of tuberculosis. Results: Significant differ...

Toward an Integrative Framework of Indigenous Research

DEFF Research Database (Denmark)

Li, Peter Ping

2012-01-01

It has long been recognized that indigenous research should be helpful, if not essential, for an adequate understanding of local phenomena. The indigenous approach is consistent with, but extends beyond, the repeated calls for contextualizing management and organization research. However, the cha......It has long been recognized that indigenous research should be helpful, if not essential, for an adequate understanding of local phenomena. The indigenous approach is consistent with, but extends beyond, the repeated calls for contextualizing management and organization research. However...

Indigenous education and heritage revitalization

NARCIS (Netherlands)

Ke, Wen-Li

2011-01-01

The thesis (working title: 'Indigenous Education and Heritage Revitalization') focuses on the (possible) roles of tangible and intangible cultural heritage in the education of indigenous peoples in Taiwan, against the background of worldwide discussions and studies of the possibilities to create and

More Like Ourselves: Indigenous Capitalism through Tourism

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Bunten, Alexis Celeste

2010-01-01

Through a comparison of Indigenous-owned cultural tourism businesses in southeastern Alaska and New Zealand as well as secondary data examining Indigenous tourism across the Pacific, this article introduces the concept of "Indigenous capitalism" as a distinct strategy to achieve ethical, culturally appropriate, and successful Indigenous…

Hospital Utilisation in Indigenous and Non-Indigenous Infants under 12 Months of Age in Western Australia, Prospective Population Based Data Linkage Study.

Science.gov (United States)

McAuley, Kimberley; McAullay, Daniel; Strobel, Natalie A; Marriott, Rhonda; Atkinson, David N; Marley, Julia V; Stanley, Fiona J; Edmond, Karen M

2016-01-01

Indigenous infants (infants aged under 12 months) have the highest hospital admission and emergency department presentation risks in Australia. However, there have been no recent reports comparing hospital utilisation between Indigenous and non-Indigenous infants. Our primary objective was to use a large prospective population-based linked dataset to assess the risk of all-cause hospital admission and emergency department presentation in Indigenous compared to non-Indigenous infants in Western Australia (WA). Secondary objectives were to assess the effect of socio-economic status (Index of Relative Socio-Economic Disadvantage [IRSD]) on hospital utilisation and to understand the causes of hospital utilisation. There were 3,382 (5.4%) Indigenous and 59,583 (94.6%) non-Indigenous live births in WA from 1 January 2010 to 31 December 2011. Indigenous infants had a greater risk of hospital admission (adjusted odds ratio [aOR] 1.90, 95% confidence interval [95% CI] 1.77-2.04, p = disadvantaged (IRSD 1) infants in the total cohort (35.7%) was similar to the risk in the least disadvantaged (IRSD 5) infants (30.6%) (aOR 1.04, 95% CI 0.96-1.13, p = 0.356). WA Indigenous infants have much higher hospital utilisation than non Indigenous infants. WA health services should prioritise Indigenous infants regardless of their socio economic status or where they live.

African Indigenous science in higher education in Uganda

Science.gov (United States)

Akena Adyanga, Francis

This study examines African Indigenous Science (AIS) in higher education in Uganda. To achieve this, I use anticolonial theory and Indigenous knowledge discursive frameworks to situate the subjugation of Indigenous science from the education system within a colonial historical context. These theories allow for a critical examination of the intersection of power relations rooted in the politics of knowledge production, validation, and dissemination, and how this process has become a systemic and complex method of subjugating one knowledge system over the other. I also employ qualitative and autoethnographic research methodologies. Using a qualitative research method, I interviewed 10 students and 10 professors from two universities in Uganda. My research was guided by the following key questions: What is African Indigenous Science? What methodology would help us to indigenize science education in Uganda? How can we work with Indigenous knowledge and anticolonial theoretical discursive frameworks to understand and challenge the dominance of Eurocentric knowledge in mainstream education? My research findings revealed that AIS can be defined in multiple ways, in other words, there is no universal definition of AIS. However, there were some common elements that my participants talked about such as: (a) knowledge by Indigenous communities developed over a long period of time through a trial and error approach to respond to the social, economic and political challenges of their society. The science practices are generational and synergistic with other disciplines such as history, spirituality, sociology, anthropology, geography, and trade among others, (b) a cumulative practice of the use, interactions with and of biotic and abiotic organism in everyday life for the continued existence of a community in its' totality. The research findings also indicate that Indigenous science is largely lacking from Uganda's education curriculum because of the influence of colonial and

Walking the Path Together: Indigenous Health Data at ICES.

Science.gov (United States)

Pyper, Evelyn; Henry, David; Yates, Erika A; Mecredy, Graham; Ratnasingham, Sujitha; Slegers, Brian; Walker, Jennifer D

2018-01-01

Indigenous data governance principles assert that Indigenous communities have a right to data that identifies their people or communities, and a right to determine the use of that data in ways that support Indigenous health and self-determination. Indigenous-driven use of the databases held at the Institute for Clinical Evaluative Sciences (ICES) has resulted in ongoing partnerships between ICES and diverse Indigenous organizations and communities. To respond to this emerging and complex landscape, ICES has established a team whose goal is to support the infrastructure for responding to community-initiated research priorities. ICES works closely with Indigenous partners to develop unique data governance agreements and supports processes, which ensure that ICES scientists must work with Indigenous organizations when conducting research that involves Indigenous peoples. © 2018 Longwoods Publishing.

Indigenous Research on Chinese Management

DEFF Research Database (Denmark)

Li, Peter Ping; Leung, Kwok; Chen, Chao C.

2012-01-01

We attempt to provide a definition and a typology of indigenous research on Chinese management as well as outline the general methodological approaches for this type of research. We also present an integrative summary of the four articles included in this special issue and show how they illustrate...... our definition and typology of indigenous research on Chinese management, as well as the various methodological approaches we advocate. Further, we introduce a commentary on the four articles from the perspective of engaged scholarship, and also three additional articles included in this issue....... Finally, we conclude with our suggestions for future indigenous research....

Isolation and Characterization of Lactic Acid Bacteria from Inasua

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Ferymon Mahulette

2017-04-01

Full Text Available Inasua is a traditionally product of wet salt fish fermentation produced by Teon, Nila and Serua (TNS Communities in Central Maluku, Indonesia. The community made this fermented fish to anticipate the lean time when fisherman could not go to sea.  The  fish that used as inasua raw material is demersal fishes that live around coral reefs, such as Samandar fish (Siganatus guttatus, Gala-gala fish (Lutjanus sp. and Sikuda fish (Lethrinus ornatus. The objective of the research was to isolate and characterize of bacterial indigenous in  Inasua from three producers in Seram Island. The measurement of pH from inasua samples were 5.9, 5.0 and 5.8, respectively. The highest number of lactic acid bacteria was found from  Gala – gala inasua was 2,5x107 cfu/g sample. Isolation of all isolates bacteria from inasua showed that a total of 7 isolates of bacteria was obtained  from Samadar inasua, 9 isolates from  Gala-gala inasua, and 7 isolates from  Sikuda inasua.  From a total of 23 isolates, only 6 isolates had characteristic as lactic acid bacteria that were Gram  positive, negative catalase, and cocci shape. The microscopic characteristics  of the isolates are coccid in pairs or uniforms which combine to form tetrads. Carbohydrate utilization test  of selected isolate by using API 50 CHB kit indicated that 13 carbohydrates are fermented by these isolates  after incubation for 48 hours. The research  was concluded that the dominant bacteria in inasua sample  is  cocci-lactic acid bacteria. Keywords : fermented fish, inasua, lactic acid bacteria, MRSA medium

Synthesis of argentojarosite with simulated bioleaching solutions produced by Acidithiobacillus ferrooxidans

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, Chiranjit [Department of Microbiology, Ohio State University, 484 West 12" t" h Avenue, Columbus, OH 43210 (United States); Jones, F. Sandy; Bigham, Jerry M. [School of Environment and Natural Resources, Ohio State University, 2021 Coffey Road, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 West 12" t" h Avenue, Columbus, OH 43210 (United States)

2016-09-01

Argentojarosite (AgFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}) is formed as a secondary phase in Ag-catalyzed bioleaching of chalcopyrite (CuFeS{sub 2}), but to date very little is known about the paragenesis or characteristics of this silver-containing compound. The purpose of this study was to synthesize argentojarosite via biological oxidation of 120 mM ferrous sulfate by Acidithiobacillus ferrooxidans. Because of its toxicity to A. ferrooxidans, Ag{sup +} (as AgNO{sub 3}) was added to spent culture media (pH 2) after complete oxidation of ferrous sulfate. Schwertmannite (ideally Fe{sub 8}O{sub 8}(OH){sub 6}(SO{sub 4})) was precipitated during the iron oxidation phase, and subsequent Ag{sup +} addition resulted in the formation of argentojarosite. Contact time (8 h, 5 d, and 14 d) and Ag{sup +} concentration (0, 5, 20, and 40 mM) were used as variables in these experiments. Synthesis of argentojarosite, schwertmannite and other mineral phases was confirmed through X-ray diffraction analysis. Additional analyses of solid-phase oxidation products included elemental composition, color and specific surface area. The sample synthesized in the presence of 40 mM Ag{sup +} and with 14 d contact time yielded an X-ray diffraction pattern of well crystallized argentojarosite, and its elemental composition closely matched the calculated Ag, Fe, and S contents of ideal argentojarosite. The color and surface area of the remaining samples were influenced by the presence of residual schwertmannite. This phase remained stable over the time course of 14 d when no Ag{sup +} was present in the system. When equilibrations were extended to 42 d, partial conversion of reference schwertmannite to goethite was noted in the absence of Ag. In the presence of 20 mM or 40 mM Ag over the same time course, some formation of argentojarosite was also noted. In this case, schwertmannite was the only source of Fe and SO{sub 4} for argentojarosite formation. - Highlights: • Iron-oxidizing bacteria

Synthesis of argentojarosite with simulated bioleaching solutions produced by Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

th Avenue, Columbus, OH 43210 (United States))" data-affiliation=" (Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States))" >Mukherjee, Chiranjit; Jones, F. Sandy; Bigham, Jerry M.; th Avenue, Columbus, OH 43210 (United States))" data-affiliation=" (Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States))" >Tuovinen, Olli H.

2016-01-01

Argentojarosite (AgFe 3 (SO 4 ) 2 (OH) 6 ) is formed as a secondary phase in Ag-catalyzed bioleaching of chalcopyrite (CuFeS 2 ), but to date very little is known about the paragenesis or characteristics of this silver-containing compound. The purpose of this study was to synthesize argentojarosite via biological oxidation of 120 mM ferrous sulfate by Acidithiobacillus ferrooxidans. Because of its toxicity to A. ferrooxidans, Ag + (as AgNO 3 ) was added to spent culture media (pH 2) after complete oxidation of ferrous sulfate. Schwertmannite (ideally Fe 8 O 8 (OH) 6 (SO 4 )) was precipitated during the iron oxidation phase, and subsequent Ag + addition resulted in the formation of argentojarosite. Contact time (8 h, 5 d, and 14 d) and Ag + concentration (0, 5, 20, and 40 mM) were used as variables in these experiments. Synthesis of argentojarosite, schwertmannite and other mineral phases was confirmed through X-ray diffraction analysis. Additional analyses of solid-phase oxidation products included elemental composition, color and specific surface area. The sample synthesized in the presence of 40 mM Ag + and with 14 d contact time yielded an X-ray diffraction pattern of well crystallized argentojarosite, and its elemental composition closely matched the calculated Ag, Fe, and S contents of ideal argentojarosite. The color and surface area of the remaining samples were influenced by the presence of residual schwertmannite. This phase remained stable over the time course of 14 d when no Ag + was present in the system. When equilibrations were extended to 42 d, partial conversion of reference schwertmannite to goethite was noted in the absence of Ag. In the presence of 20 mM or 40 mM Ag over the same time course, some formation of argentojarosite was also noted. In this case, schwertmannite was the only source of Fe and SO 4 for argentojarosite formation. - Highlights: • Iron-oxidizing bacteria were used to oxidize Fe 2+ in the absence of K + and NH 4 + . �

Kahwà:tsire: Indigenous Families in a Family Therapy Practice with the Indigenous Worldview as the Foundation

OpenAIRE

Derrick, J.M.

2017-01-01

This study creates new knowledge regarding the impact of European colonization on Indigenous (Aboriginal, First Nations, Inuit, Metis) families in Canada. It particularly focuses on the issues in families whose children were forcibly removed by the government to institutions called residential schools. Members of Indigenous families voluntarily attended a family therapy practice which utilized a family systems approach and was uniquely based in the Indigenous worldview. This worldview is spir...

A Comparison between Australian Football League (AFL Injuries in Australian Indigenous versus Non-indigenous Players

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Jessica Orchard

2013-09-01

Full Text Available It has previously been shown that being of aboriginal descent is a risk factor for hamstring injuries in Australian football. The aim of this study was to review the Australian Football League (AFL injury database to determine whether there were any injuries where indigenous players had different relative risks to non-indigenous players. Analysis was conducted using data from the AFL injury database, which included data from 4,492 players over 21 years (1992–2012, covering 162,683 player-matches at AFL level, 91,098 matches at lower levels and 328,181 weeks (possible matches of exposure. Compared to non-indigenous players, indigenous players had a significantly higher risk of hamstring injuries (RR 1.52, 95% CI 1.32–1.73 and calf strains (RR 1.30, 95% CI 1.00–1.69. Conversely, indigenous players had a significantly lower risk of lumbar/thoracic spine injuries (RR 0.61, 95% CI 0.41–0.91, groin strains/osteitis pubis (RR 0.75, 95% CI 0.58–0.96 and Achilles tendon injuries (RR 0.32, 95% CI 0.12–0.86. The results for the above injuries were also significant in terms of games missed. There was no difference between overall risk of injury (RR 1.03, 95% CI 0.96–1.10 or missed games (RR 1.00, 95% CI 0.97–1.04. This suggests that indigenous AFL players have the same overall number of injuries and missed games, but a slightly different injury profile.

Cardiovascular dynamics of Canadian Indigenous peoples.

Science.gov (United States)

Foulds, Heather J A; Bredin, Shannon S D; Warburton, Darren E R

2018-12-01

Limited understanding of Indigenous adults' cardiovascular structure and function exists despite high rates of cardiovascular disease. This investigation characterised cardiovascular structure and function among young Indigenous adults and compared to age- and sex-matched European descendants. Echocardiographic assessments included apical two- and four-chamber images, parasternal short-axis images and Doppler. Analyses included cardiac volumes, dimensions, velocities and strains. Cardiovascular structure and function were similar between Indigenous (n=10, 25 ± 3 years, 4 women) and European-descendant (n=10, 24 ± 4 years, 4 women,) adults, though European descendants demonstrated greater systemic vascular resistance (18.19 ± 3.94 mmHg∙min -1 ∙L -1 vs. 15.36 ± 2.97 mmHg∙min -1 ∙L -1 , p=0.03). Among Indigenous adults, women demonstrated greater arterial elastance (0.80 ± 0.15 mmHg·mL -1 ·m -2 vs. 0.55 ± 0.17 mmHg·mL -1 ·m -2 , p=0.02) and possibly greater systemic vascular resistance (17.51 ± 2.20 mmHg∙min -1 ∙L -1 vs. 13.93 ± 2.61 mmHg∙min -1 ∙L -1 , p=0.07). Indigenous men had greater cardiac size, dimensions and output, though body size differences accounted for cardiac size differences. Similar cardiac rotation and strains were observed across sexes. Arterial elastance and cardiac size were different between Indigenous men and women while cardiovascular structure and function may be similar between Indigenous and European descendants.

Indigenous rights, performativity and protest

NARCIS (Netherlands)

Hanna, Philippe; Langdon, Esther Jean; Vanclay, Frank

Protests to claim rights are a common practice among Indigenous peoples of the world, especially when their interests conflict with those of nation states and/or multinational corporations regarding the use of their lands and resources. Drawing on a case study of the National Indigenous Mobilization

Protecting indigenous land from mining

NARCIS (Netherlands)

Borde, Radhika

2017-01-01

Support for indigenous peoples has been increasing over the last few decades. This can be seen internationally, as well as in several domestic contexts. The support for indigenous people has been linked to the increasingly prominent impetus to conserve the Earth’s biodiversity and environment.

Indigenous participation and representation in Venezuelan electoral processes

Directory of Open Access Journals (Sweden)

Luis Fernando ANGOSTO FERRÁNDEZ

2012-06-01

Full Text Available This article examines the Venezuelan regional elections of 2008 as a contextual event for the analysis of electoral strategies and results associated with the indigenous representation. Three factors intertwined in the electoral moment are analyzed: 1. the existence of minimum guaranteed representation for indigenous population in legislative organs; 2. the participation of indigenous candidates and electors; 3. the maneuvers of political parties and civil organizations that attempt to channel and/or benefit from such indigenous representation and participation. The description of the electoral context facilitates the identification of factors that, beyond the normative structure of the State, condition the agency of individuals and parties involved in electoral processes. Among those factors are the symbolic value of indigeneity in the current process of national identity re-definition, the interest of political parties in controlling the vote of the indigenous representation and the tendency towards the consolidation of professionalized elites within the indigenous activism.

Integrating indigenous games and knowledge into Physical Education

African Journals Online (AJOL)

Integrating indigenous games and knowledge into Physical Education: Implications for ... The aim of this study was to analyse indigenous Zulu games towards integrating indigenous game skill and knowledge ... AJOL African Journals Online.

Surface characterization of bacterial cells relevant to the mineral industry

NARCIS (Netherlands)

Sharma, PK; Rao, KH

Bacteria belonging to the Acidithiobacilli group are widely used in the mineral processing industry in bioleaching and biobeneficiation operations. Paenibacillus polymyxa has also found application in biobeneficiation studies. Microbial adhesion to mineral surface is an essential step,for both

Biostimulation of indigenous microbial community for bioremediation of petroleum refinery sludge.

Directory of Open Access Journals (Sweden)

Jayeeta Sarkar

2016-09-01

Full Text Available Nutrient deficiency severely impairs the catabolic activity of indigenous microorganisms in hydrocarbon rich environments (HREs and limits the rate of intrinsic bioremediation. The present study aimed to characterize the microbial community in refinery waste and evaluate the scope for biostimulation based in situ bioremediation. Samples recovered from the wastewater lagoon of Guwahati refinery revealed a hydrocarbon enriched high total petroleum hydrocarbon (TPH, oxygen-, moisture-limited, reducing environment. Intrinsic biodegradation ability of the indigenous microorganisms was enhanced significantly (>80% reduction in TPH by 90 days with nitrate amendment. Preferred utilization of both higher- (>C30 and middle- chain (C20-30 length hydrocarbons were evident from GC-MS analysis. Denaturing gradient gel electrophoresis (DGGE and community level physiological profiling (CLPP analyses indicated distinct shift in community’s composition and metabolic abilities following nitrogen (N amendment. High throughput deep sequencing of 16S rRNA gene showed that the native community was mainly composed of hydrocarbon degrading, syntrophic, methanogenic, nitrate/iron/sulfur reducing facultative anaerobic bacteria and archaebacteria, affiliated to γ- and δ-Proteobacteria and Euryarchaeota respectively. Genes for aerobic and anaerobic alkane metabolism (alkB and bssA, methanogenesis (mcrA, denitrification (nirS and narG and N2 fixation (nifH were detected. Concomitant to hydrocarbon degradation, lowering of dissolve O2 and increase in oxidation-reduction potential (ORP marked with an enrichment of N2 fixing, nitrate reducing aerobic/facultative anaerobic members e.g., Azovibrio, Pseudoxanthomonas and Commamonadaceae members was evident in N amended microcosm. This study highlighted that indigenous community of refinery sludge was intrinsically diverse, yet appreciable rate of in situ bioremediation could be achieved by supplying adequate N sources.

Biostimulation of Indigenous Microbial Community for Bioremediation of Petroleum Refinery Sludge

Science.gov (United States)

Sarkar, Jayeeta; Kazy, Sufia K.; Gupta, Abhishek; Dutta, Avishek; Mohapatra, Balaram; Roy, Ajoy; Bera, Paramita; Mitra, Adinpunya; Sar, Pinaki

2016-01-01

Nutrient deficiency severely impairs the catabolic activity of indigenous microorganisms in hydrocarbon rich environments (HREs) and limits the rate of intrinsic bioremediation. The present study aimed to characterize the microbial community in refinery waste and evaluate the scope for biostimulation based in situ bioremediation. Samples recovered from the wastewater lagoon of Guwahati refinery revealed a hydrocarbon enriched [high total petroleum hydrocarbon (TPH)], oxygen-, moisture-limited, reducing environment. Intrinsic biodegradation ability of the indigenous microorganisms was enhanced significantly (>80% reduction in TPH by 90 days) with nitrate amendment. Preferred utilization of both higher- (>C30) and middle- chain (C20-30) length hydrocarbons were evident from GC-MS analysis. Denaturing gradient gel electrophoresis and community level physiological profiling analyses indicated distinct shift in community’s composition and metabolic abilities following nitrogen (N) amendment. High throughput deep sequencing of 16S rRNA gene showed that the native community was mainly composed of hydrocarbon degrading, syntrophic, methanogenic, nitrate/iron/sulfur reducing facultative anaerobic bacteria and archaebacteria, affiliated to γ- and δ-Proteobacteria and Euryarchaeota respectively. Genes for aerobic and anaerobic alkane metabolism (alkB and bssA), methanogenesis (mcrA), denitrification (nirS and narG) and N2 fixation (nifH) were detected. Concomitant to hydrocarbon degradation, lowering of dissolve O2 and increase in oxidation-reduction potential (ORP) marked with an enrichment of N2 fixing, nitrate reducing aerobic/facultative anaerobic members [e.g., Azovibrio, Pseudoxanthomonas and Comamonadaceae members] was evident in N amended microcosm. This study highlighted that indigenous community of refinery sludge was intrinsically diverse, yet appreciable rate of in situ bioremediation could be achieved by supplying adequate N sources. PMID:27708623

Indigenous knowledges driving technological innovation

Science.gov (United States)

Lilian Alessa; Carlos Andrade; Phil Cash Cash; Christian P. Giardina; Matt Hamabata; Craig Hammer; Kai Henifin; Lee Joachim; Jay T. Johnson; Kekuhi Kealiikanakaoleohaililani; Deanna Kingston; Andrew Kliskey; Renee Pualani Louis; Amanda Lynch; Daryn McKenny; Chels Marshall; Mere Roberts; Taupouri Tangaro; Jyl Wheaton-Abraham; Everett. Wingert

2011-01-01

This policy brief explores the use and expands the conversation on the ability of geospatial technologies to represent Indigenous cultural knowledge. Indigenous peoples' use of geospatial technologies has already proven to be a critical step for protecting tribal self-determination. However, the ontological frameworks and techniques of Western geospatial...

Population structure of four Thai indigenous chicken breeds.

Science.gov (United States)

Mekchay, Supamit; Supakankul, Pantaporn; Assawamakin, Anunchai; Wilantho, Alisa; Chareanchim, Wanwisa; Tongsima, Sissades

2014-03-27

In recent years, Thai indigenous chickens have increasingly been bred as an alternative in Thailand poultry market. Due to their popularity, there is a clear need to improve the underlying quality and productivity of these chickens. Studying chicken genetic variation can improve the chicken meat quality as well as conserving rare chicken species. To begin with, a minimal set of molecular markers that can characterize the Thai indigenous chicken breeds is required. Using AFLP-PCR, 30 single nucleotide polymorphisms (SNPs) from Thai indigenous chickens were obtained by DNA sequencing. From these SNPs, we genotyped 465 chickens from 7 chicken breeds, comprising four Thai indigenous chicken breeds--Pradhuhangdum (PD), Luenghangkhao (LK), Dang (DA) and Chee (CH), one wild chicken--the red jungle fowls (RJF), and two commercial chicken breeds--the brown egg layer (BL) and commercial broiler (CB). The chicken genotypes reveal unique genetic structures of the four Thai indigenous chicken breeds. The average expected heterozygosities of PD=0.341, LK=0.357, DA=0.349 and CH=0.373, while the references RJF= 0.327, CB=0.324 and BL= 0.285. The F(ST) values among Thai indigenous chicken breeds vary from 0.051 to 0.096. The F(ST) values between the pairs of Thai indigenous chickens and RJF vary from 0.083 to 0.105 and the FST values between the Thai indigenous chickens and the two commercial chicken breeds vary from 0.116 to 0.221. A neighbour-joining tree of all individual chickens showed that the Thai indigenous chickens were clustered into four groups which were closely related to the wild RJF but far from the commercial breeds. Such commercial breeds were split into two closely groups. Using genetic admixture analysis, we observed that the Thai indigenous chicken breeds are likely to share common ancestors with the RJF, while both commercial chicken breeds share the same admixture pattern. These results indicated that the Thai indigenous chicken breeds may descend from the

Indigenous housing and health in the Canadian North

DEFF Research Database (Denmark)

Christensen, Julia

2016-01-01

In this article, I explore the relationship between housing, home and health amongst Indigenous homeless people living in the Canadian North. In particular, I examine the ways in which Indigenous homemaking practices conflict with housing policy, and exacerbate individual pathways to homelessness....... I argue that integral components in northern Indigenous conceptualizations of home and, in turn, health are not only unrecognized in housing policy, but actively discouraged. The potential for homemaking to inform health and housing policy speaks to the relevance of cultural safety not only...... to Indigenous health services, but also to a comprehensive framing of Indigenous health....

Rehabilitation and indigenous peoples: the Māori experience.

Science.gov (United States)

Harwood, Matire

2010-01-01

Indigenous peoples often have the worst health status in comparison to non-indigenous people in their own nations; urgent action to address the health inequities for indigenous people is required. The role of rehabilitation in addressing health and disability inequities is particularly important due to the health need of indigenous peoples; the unequal distribution of health determinants; and disparities in access to, quality of care through and outcomes following rehabilitation. This article will present a perspective for Māori, the indigenous peoples of New Zealand, on a framework for improving rehabilitation services for Māori and ultimately their health and wellbeing.

The Portrayal of Indigenous Health in Selected Australian Media

Directory of Open Access Journals (Sweden)

Melissa J. Stoneham

2014-04-01

Full Text Available It is acknowledged that health outcomes for Australian Indigenous peoples are lower than those of non-Indigenous Australians. Research suggests negative media in relation to Indigenous Australians perpetuates racist stereotypes among the wider population and impacts on the health of Indigenous Australians. This study examined the media portrayal of Indigenous Australian public health issues in selected media over a twelve month period and found that, overwhelmingly, the articles were negative in their portrayal of Indigenous health. A total of 74 percent of the coverage of Australian Indigenous related articles were negative, 15 percent were positive, and 11 percent were neutral. The most common negative subject descriptors related to alcohol, child abuse, petrol sniffing, violence, suicide, deaths in custody, and crime.