The Effect of the Facultative Chemolithotrophic Bacterium Thiobacillus acidophilus on the Leaching of Low-Grade Cu-Ni Sulfide Ore by Thiobacillus ferrooxidans

The purpose of this investigation was to determine the effect of Thiobacillus acidophilus on the leaching of a low-grade Cu-Ni sulfide ore by Thiobacillus ferrooxidans. A sample of low-grade Cu-Ni sulfide ore containing 0.36% Cu, 0.48% Ni, and 7.87% Fe was pulverized and initially leached for a 21-day period using two different pure cultures of T. ferrooxidans, an environmental strain (F2) and a strain from the American Type Culture Collection (ATCC 23270). Samples of the ore slurries were drawn and the pH was monitored over the course of the leaching period. The concentrations of Cu and Ni leached by each strain were determined and compared. No significant differences were observed in the concentrations of Cu and Ni leached by the two pure cultures of T. ferrooxidans. Subsequently, the ore was leached with mixed cultures of T. ferrooxidans and T. acidophilus to determine the effect of the latter on the concentrations of Cu and Ni leached from the ore. The environmental strain F2 of T. ferrooxidans was used in combination with both a type strain (ATCC 27807) and an environmental strain (64) of T. acidophilus. After 21 days, the mixed cultures of T. ferrooxidans and T. acidophilus leached significantly greater amounts of copper than the pure strain alone, but no such difference was observed for the leaching of nickel.     

Leaching Heavy Metals from Contaminated Soil by Using Thiobacillus ferrooxidans or Thiobacillus thiooxidans

Iron- and sulfur-oxidizing bacteria identified as Thiobacillus ferrooxidans and T. thiooxidans were successfully enriched from various soil samples contaminated with heavy metals and organic compounds. Depending on the growth medium, the soil sample, and the type of contaminant, the indigenous isolates solubilized > 50% of most of the heavy metals present in the solid sample (As, Cd, Co, Cr, Cu, Ni, V, Zn, B, Be). Leaching with T. ferrooxidans strains resulted in total extraction of Cd, Co, Cu, and Ni. With sulfur-oxidizing bacteria > 80% of Cd, Co, Cu, and Zn was mobilized from rainwater sludge. Pb and Ba were not detected in the leachate, given the insolubility of their sulfate compounds. An increase in pulp density up to 20%, indicating 6.6% total organic carbon in the soil and rubble leach experiment (sample 557), did not inhibit the growth of the indigenous T. ferrooxidans strain. In view of these results, bioleaching appears to have some potential for remediation of heavy metal contaminated soils.     

氧化硫硫杆菌的研究进展

综述了氧化硫硫杆菌(Thiobacillus thiooxidans,T.t)培养方法和应用方面的研究进展。     

氧化亚铁硫杆菌培养过程中沉淀的研究

为了减少氧化亚铁硫杆菌培养过程中产生的沉淀,对氧化亚铁硫杆菌培养过程中产生的沉淀物进行了研究,确定了在pH为1．5,K2HPO4用量为0．25g/l,KH2PO4为0．195g/l时菌体可以保持其最高氧化活性,同时产生最少量沉淀物的培养条件,并发现沉淀物对菌体的生长和氧化Fe^2 没有影响。利用饥饿状态的氧化亚铁硫杆菌证明了菌体在一定条件下可以利用黄铁钒沉淀中的部分离子进行生长繁殖。     

Bio-oxidation of iron using Thiobacillus ferrooxidans

The effects of pH, ferrous and ferric ion concentrations on iron oxidation by Thiobacillus ferrooxidans were examined. The initial temperature and bacterial concentration were maintained at 37°C and 2±1×104cells/ml, respectively. The iron oxidation rate increased with increased initial ferrous iron concentration to 4g/l and thereafter decreased. The presence of iron(III) showed a negative effect on the bacterial iron oxidation rate. The increase of pH also showed an increase in the oxidation rate up to pH 1.75. The oxidation rate followed first order kinetics for the parameters studied. A rate equation has been developed.     

Chemotaxis of chemolithotrophic Thiobacillus ferrooxidans toward thiosulfate

Abstract The chemotactic response of Thiobacillus ferrooxidans toward thiosulfate was observed. The traditional assay technique was modified by direct microscopic enumeration of cells which moved into the attractant solution. The optimum concentration shown by thiosulfate-grown cells, tetrathionate-grown cells as well as iron-grown cells was 10³ times the optimum concentration shown by cells grown on elemental sulfur. Iron-grown cells which lack thiosulfate-oxidizing activity showed increased accumulation at optimum concentration as compared to cells grown on elemental sulfur and other reduced sulfur compounds. This indicated the constitutive nature of chemotaxis by T. ferrooxidans toward thiosulfate.     

氧化亚铁硫杆菌固定化技术研究

在生物脱硫过程中 ,以H - 2软性填料作为氧化亚铁硫杆菌 (Thiobacillusferrooxidans)的固定化载体 ,构建了固定床生化反应器。考察了不同稀释率固定下床生化反应器氧化Fe2 + 的情况 ,在通气量为 330L/h ,稀释率为 0 6h-1条件下 ,Fe2 + 最大氧化速率达 7 6 7g[Fe2 + ]/L·h。该反应器连续运行 10 0d,固定化细胞稳定性良好     

A novel membrane-bound flavocytochrome c sulfide dehydrogenase from the colourless sulfur bacterium Thiobacillus sp. W5

A novel membrane-bound sulfide-oxidizing enzyme was purified 102-fold from the neutrophilic, obligately chemolithoautotrophic Thiobacillus sp. W5 by means of a six-step procedure. Spectral analysis revealed that the enzyme contains haem c and flavin. SDS-PAGE showed the presence of two types of subunit with molecular masses of 40 and 11 kDa. The smaller subunit contains covalently bound haem c, as was shown by haem staining. A combination of spectral analysis and the pyridine haemochrome test indicated that the sulfide-oxidizing heterodimer contains one molecule of haem c and one molecule of flavin. It appeared that the sulfide-oxidizing enzyme is a member of a small class of redox proteins, the flavocytochromes c, and is structurally most related to the flavocytochrome c sulfide dehydrogenase of the green sulfur bacterium Chlorobium limicola. The pH optimum of the enzyme is 8.6. At pH 9, the V _max was 2.1 ± 0.1 μmol cytochrome c (mg protein)^–1 min^–1, and the K _m values for sulfide and cytochrome c were 1.7 ± 0.4 μM and 3.8 ± 0.8 μM, respectively. Cyanide inhibited the enzyme by the formation of an N-5 adduct with the flavin moiety of the protein. On the basis of electron transfer stoichiometry, it seems likely that sulfur is the oxidation product. Received: 15 October 1996 / Accepted: 7 January 1997     

Enhancement of Copper Dissolution from a Sulfide Ore by Using Thiobacillus thiooxidans

Copper dissolution from a sulfide ore (with covellite as the main copper phase) was investigated in cultures of Thiobacillus ferrooxidans or Thiobacillus thiooxidans and in abiotic controls. In unsupplemented media, T. ferrooxidans was more efficient than T. thiooxidans. In the presence of ferric iron, the dissolution of covellite was not significantly different in cultures inoculated with T. ferrooxidans or T. thiooxidans. However, the most extraction was found in T. thiooxidans cultures supplemented with ferrous sulfate. The first results were explained by the mechanism proposed by Schippers and Sand (Appl Envir Microbiol 65:319-321, 1999), which involves polysulfides and sulfur as intermediates. This mechanism was extended to explain the behavior of T. thiooxidans culture supplemented with ferrous iron.     

Metal resistance and plasmid DNA in Thiobacillus ferrooxidans

The minimal inhibitory concentrations of copper and nickel were determined for each of fifteen isolates of T. ferrooxidans native to a Cu/Ni tailings environment. Ten isolates were inhibited by 160 mM Cu,²⁺ or less, and ten were inhibited by 160 mM Ni²⁺or less. The isolates were screened for plasmid DNA using an alkaline lysis method and CCC plasmid forms were confirmed using the Hintermann technique. Two isolates were found to be devoid of plasmid DNA, and only one isolate contained more than two plasmids. Variability existed in plasmid size, although the majority were larger than the standard pBR322 (4.3 kbp). One plasmid was selected for further analysis using restriction endonucleases. EcoRI, HindIII and KpnI all cleaved the plasmid in two locations, and PstI cleaved the plasmid in six locations. PstI-digested fragments of the plasmid were ligated into pBR322, and the recombinant plasmids were transformed into Escherichia coli ATCC 8739. Four genetically-different transformants resulted, and each was grown in media containing 2.0 mM Cu²⁺ and compared to the growth of a control under similar conditions. There was no conferred copper resistance in E. coli, although one recombinant plasmid appeared to decrease the tolerance for E. coli ATCC 8739 to Cu²⁺.     

Thermal characterization of different isolates of Thiobacillus ferrooxidans

Abstract Ten different isolates of Thiobacillus ferrooxidans were characterized with respect to temperature in the range 2–35°C. Four of the ten strains oxidized ferrous iron exponentially over the entire range of incubation temperatures, including the lowest temperature tested (2°C), and were therefore characterized as psychrotrophic. Jarosite production was substantially reduced at temperatures less than 10°C and was not observed at 2°C. Energy of activation values were in the range 75.2–96.6 kJ/mol°C and indicated that iron oxidation at low temperatures was governed by both a chemical and a physical control.     

Dissolution of sulphur particles by Thiobacillus ferrooxidans: substrate for unattached cells

The growth of Thiobacillus ferrooxidans on sulphur is known to proceed through the attachment of cells to the sulphur particles. Experiments, However, show that the cells in the liquid phase, which are not attached to the sulphur particles, also grow. It has been shown through the use of a two-compartment membrane reactor that this increase is partially due to the release of ions, corresponding to partially oxidized of sulphur, into the solution by the attached cells. The main soluble ion has been found to the thiosulphate, but traces of sulphite have also been detected. (c) 1993 John Wiley & Sons, Inc.     

Thermotolerance of adenylylsulfate reductase from Thiobacillus denitrificans

Abstract Adenylylsulfate (APS) and APS reductase are important in the energy-generating processes of sulfate-reducing bacteria and sulfur lithotrophs (phototrophs and nonphototrophs). APS reductase from an extremely thermophilic archaebacterial sulfate-reducer was recently shown to be thermophilic with optimal activity at 85°C (Speich and Truper (1988) J. Gen. Microbiol. 134, 1419–1425). APS reductase of Thiobacillus denitrificans , a mesophilic eubacterium, has biochemical and physical properties in common with the thermophilic enzyme and is also thermotolerant (up to 75°C). APS reductase and other enzymes of dissimilative inorganic sulfur metabolism may commonly be thermotolerant is mesophilic eubacteria; perhaps a vestige of their primordial significance.     

Lipopolysaccharides of Thiobacillus species containing lipid A with 2,3-diamino-2,3-dideoxyglucose

Lipopolysaccharides were isolated from two strains of Thiobacillus ferrooxidans and one strain each of Thiobacillus thiooxidans, Thiobacillus novellus and Thiobacillus sp. IFO 14570. Neutral sugars, 2-keto-3-deoxyoctonate, fatty acids and the rare 2,3-diamino-2,3-dideoxyglucose were detected in all lipopolysaccharides. Lipopolysaccharides of both T. ferrooxidans strains contained l-glycero-d-manno-heptose, whereas that of T. thiooxidans contained both l-glycero-d-manno-heptose and d-glycero-d-manno-heptose. On the other hand, heptoses were absent in lipopolysaccharides of T. novellus and Thiobacillus sp. IFO 14570. Lipid A of T. ferrooxidans and T. thiooxidans contained both glucosamine and 2,3-diamino-2,3-dideoxyglucose, in contrast, lipid A of T. novellus and the Thiobacillus sp. IFO 14570 most likely contain only 2,3-diamino-2,3-dideoxyglucose as backbone sugar. Deoxycholate polyacrylamide gel electrophoresis revealed S-type character for all lipopolysaccharides studied. The significance of the lipopolysaccharide composition for taxonomic and phylogenetic questions with regard to thiobacilli is discussed.Abbreviations DAG 2,3-diamino-2,3-dideoxyglucose - DOC sodium deoxycholate - GC gas-liquid chromatography - GC/MS gas-liquid chromatography/mass spectrometry - d,d-Heptose d-glycero-d-manno-heptose - l,d-Heptose l-glycero-d-manno-heptose - KDO 2-keto-3-deoxyoctonate - LPS lipopolysaccharide - 3-OH-14:0 3-hydroxy-tetradecanoic acid - PAGE polyacrylamide gel electrophoresis - PCP phenol-chloroform-petroleum ether     

Influence of lipopolysaccharides on the attachment of Thiobacillus ferrooxidans to minerals

The loss of part of the lipopolysaccharides (LPS) of the outer membrane of T. ferrooxidans negatively influenced the attachment of the bacteria to minerals and the bioleaching process. LPS previously extracted from T. ferrooxidans and which had come into contact with pyrite inhibited the attachment of cells to minerals and also negatively affected the bioleaching. These results suggest that LPS play an important role in the attachment of the microorganisms and therefore, its presence or absence could affect the bioleaching process.     

氧化亚铁硫杆菌氧化亚硫酸盐的动力学研究

实验用Ms培养基,利用去除铁离子的氧化亚铁硫杆菌(Thiobacillus ferrooxidans)进行了细菌亚硫酸盐的生长代谢研究。实验结果表明氧化亚铁硫杆菌对亚硫酸根具有一定的氧化能力。用Origin 7.0对实验数据进行拟合处理,表明了氧化亚铁硫杆菌催化氧化亚硫酸盐的动力学方程符合Hill方程。氧化亚铁硫杆菌催化氧化亚硫酸盐是一个底物抑制的细胞反应,其KS值随pH值和底物浓度的改变而变化。pH值对反应有很大的影响,pH值越接近中性KS就越小,反应速率就越大。     

Resistance to heavy metals in different strains of Thiobacillus ferrooxidans

Ten different isolates of Thiobacillus ferrooxidans were studied with regard to their degree of resistance to the metals copper, nickel, uranium, and thorium. Inhibitory concentrations for a particular metal were those which showed a statistically-significant decrease in the amount of ferrous iron oxidized by the bacterium compared to an untreated control. The different isolates had different susceptibilities to the metals tested, and none of the metals had a stimulatory effect. Uranium and thorium were 20 to 40 times more toxic to ferrous iron oxidation than either copper or nickel.     

The reductive reactions of Thiobacillus ferrooxidans on sulphur and selenium

Abstract An investigation into the sulphur oxidation of iron grown Thiobacillus ferrooxidans is reported. A new mechanism for sulphur catabolism in this obligate acidophile, involving the initial reduction of the substrate, is proposed. Evidence to support substrate reduction comes from the evolution of H₂S in both aerobic and anaerobic conditions (O₂ and Fe³⁺ acting as terminal electron acceptors, respectively) and a accurate trapping method of detection is described. Levels of sulphur reduction are such that a role in the full catabolism of sulphur can be envisaged. In addition, red selenium reduction was investigated and the bioenergetic implications for both substrates are discussed.     

Nitrate-Controlled Anaerobic Oxidation of Pyrite by Thiobacillus Cultures

Nitrate-dependent pyrite oxidation is an important process as it may prevent pollution by nitrate from agriculture. Anaerobic oxidation of pyrite with nitrate as an electron acceptor was studied in cultures of Thiobacillus denitrificans and Thiobacillus thioparus. Both strains reduced nitrate, with pyrite added as sole electron donor, but T. thioparus reduced nitrate to nitrite only. Accumulation of nitrite, however, was prevented in co-cultures of T. denitrificans and T. thioparus. Furthermore, pyrite oxidation rates were dependent on pyrite pretreatment, which results in different specific surface areas of pyrite. Initial nitrate concentration or pyrite origin did not affect the pyrite oxidation rate.