Optimal production of sulphuric acid by Thiobacillus thiooxidans using response surface methodology

Response surface methodology was applied to determine the optimal medium composition for sulphuric acid production by an indigenous Thiobacillus thiooxidans. With a view to reducing the number of experiments and obtaining the mutual interactions between the variables, a 2⁴ full-factorial central composite design was employed for experimental design and analysis of the results. Four independent variables, KH₂PO₄, (NH₄)₂SO₄, MgSO₄ and elemental sulphur, in the growth medium were tested. Elemental sulphur was found to exhibit positive correlation with the sulphuric acid yield, whereas the other three variables showed no significant effect. No mutual interactions were found between elemental sulphur and each of the other three variables. The optimal composition of the growth medium to achieve the optimal production of sulphuric acid was determined as follows (g/l): KH₂PO₄=3.5, (NH₄)₂SO₄=4.9, MgSO₄=0.7 and elemental sulphur=23.7. The corresponding sulphuric acid production and dry cell weight were 38 662 ppm and 0.7 g/l, which are about 2.6- and 1.75-fold increase, respectively, compared with those using the conventional T. thiooxidans optimum growth medium.     

Effects of organic matter on sulphur oxidation in soil and influence of sulphur oxidation on soil nitrification

Summary The effects of wheat straw and pressed sugar beet pulp on sulphur oxidation were determined in a loam soil amended with 1% (w/w) elemental sulphur. Wheat straw stimulated the oxidation of elemental sulphur over the first 2 to 3 weeks of the incubation period, resulting in an increase in LiCl-extractable sulphate. After 4 to 7 weeks incubation however, the only significant increase in soil sulphate followed the 1% straw addition, while at week 7 sulphate concentrations in the 0.25% and 5.0% straw amended soils were lower than the control. Pressed sugar beet pulp (1% w/w) initially stimulated the oxidation of elemental sulphur in the soil, but by weeks 3 to 7 of the incubation period rates of oxidation in pulp-amended soils were lower than the control. Towards the end of the incubation period however, sulphate concentrations in the amended soils exceeded the control values, significantly so by week 11. The concentration of thiosulphate and tetrathionate also increased in soils receiving sugar beet pulp. Nitrification was inhibited in soils in which sulphur oxidation was actively occurring. Although possible alternatives are mentioned, such inhibition appears to result from a decrease in soil pH brought about by the oxidation of elemental sulphur to sulphuric acid.     

Action of Thiobacillus thiooxidans on Sulphur in the Presence of a Surfactant Agent and its Application in the Indirect Dissolution of Phosphorus

The addition of a surfactant agent (Tween 80) to a medium containing sulphur and a culture of Thiobacillus thiooxidans increased the attachment of bacteria to sulphur, the rate of sulphur oxidation and sulphuric acid production. This acid was used to dissolve phosphorus from calcium phosphate. The yield was higher than reported for other microorganisms although dissolution was not increased significantly by Tween addition.     

Preliminary proteomic analysis of Thiobacillus ferrooxidans growing on elemental sulphur and Fe2+ separately

Thiobacillus ferrooxidans is one of the most important bacterium used in bioleaching, and can utilize Fe2+ or sulphide as energy source. Growth curves for Thiobacillus ferrooxidans have been tested, which show lag, logarithmic, stationary and aging phases as seen in other bacteria. The logarithmic phases were from 10 to 32 hours for Thiobacillus ferrooxidans cultivated with Fe2+ and from 4 to 12 days for Thiobacillus ferrooxidans cultivated with elemental sulphur. Differences of protein patterns of Thiobacillus ferrooxidans growing on elemental sulphur and Fe2+ separately were investigated after cultivation at 30 degrees C by the analysis of two-dimensional gel electrophoresis (2-DE), matrix-assisted laser desorption/ ionization (MALDI)-Mass spectrometry and ESI-MS/MS. From the 17 identified protein spots, 11 spots were found more abundant when growing on elemental sulphur. By contrast 6 protein spots were found decreased at elemental cultivation condition. Among the proteins identified, cytochrome C have been previously identified as necessary elements of electron-transferring pathway for Thiobacillus ferrooxidans to oxidize Fe2+; ATP synthase alpha chain and beta are expressed increased when Thiobacillus ferrooxidans cultivated with Fe2+ as energy source. ATP synthase Beta chain is the catalytic subunit, and ATP synthase alpha chain is a regulatory subunit. The function of ATPase produces ATP from ADP in the presence of a proton gradient across the membrane.     

二氧化硫污染对植物体酶活性的影响

通过用６种浓度的ＳＯ２气体对６种植物进行熏气处理,然后测定植物叶片内的过氧化物酶,抗坏血酸氧化酶及多酚氧化酶的活性,为环境监测提供理论依据。通过试验,发现ＳＯ２气体对植物叶内不同酶的活性的影响有别。６种植物受不同浓度的ＳＯ２污染,叶内的过氧化物酶活性随ＳＯ２浓度增加而增加,促进叶片的衰老;而对其他的２种酶,则６种植物表现不同     

Preliminary Evidence for a Sulphur Cycle in Movile Cave,Romania

In order to investigate the food chain and energy balance of the chemolithoautotrophically‐based ecosystem of the sulphur spring in Movile Cave as a model system for extraterrestrial life, a first sampling campaign was done. Microbial diversity and activity were analysed by MPN‐enumeration methods and microcalorimetry, respectively. In addition, a speciation of the inorganic sulphur compounds by HPLC and IC techniques was performed. Metabolic activities were predominantly connected with thick microbial mats floating on the water surface of the cave. These mats showed an aerobic heat evolution of about 1200 μW/g and contained about 500 μmol/g elemental sulphur. In contrast, other samples collected from cave water, sediment and rock exhibited only activities of maximal 40 to 60 μW/g and contained only up to 2.5 μmol/g elemental sulphur. As the main primary producers aerobic and facultatively anaerobic sulphur oxidisers were identified at high numbers, occasionally exceeding 10⁷ CFU/g. Methylotrophic bacteria were present in all samples at up to 10⁶ CFU/g, indicating the important role of C1 metabolism for the cave ecosystem. Although reduced sulphur species were biologically oxidised to sulphuric acid, the pH values of the samples ranged from 6.5 to 8.2 due to the high buffering capacity of the cave walls, which consisted mainly of limestone. Surprisingly, not only neutrophilic but also extremely acidophilic bacteria were detected. Sulphate reducers were present in both aerobic and anaerobic zones. The data presented suggest a close interdependence of sulphur oxidation and reduction as well as carbon dioxide and other C1 compound metabolism in the most biologically active zone of the cave ecosystem, i.e. the floating microbial mats.     

Cysteine and methionine-precursors of methyl sulphone metabolites of 2,4',5-trichlorobiphenyl in mice

In order to account for the origin of the sulphur atom in methyl sulphones derived from polychlorinated biphenyls (PCB), groups of mice were treated with 2,4'-5-trichlorobiphenyl and [35S]cysteine or [35S]methionine, respectively. Control animals received the labelled amino acids only. The radioactive substances extracted from lung tissue were characterized by partition between hexane and sulphuric acid, thin-layer radiochromatography (TLRC), gas chromatography (GC) and mass fragmentography (MF). In lung extracts of both experimental groups sulphuric acid soluble metabolites were present: Their Rf-values on TLRC were identifical with that of 4-methylsulphonyl-2,4'-5-trichlorobiphenyl and their identity was confirmed by GC and GC-MF, which also indicated the presence of a minor sulphone isomer. The study shows that both cysteine and methionine could function as donors of the sulphur atom in the methyl sulphone metabolites derived from PCB.     

Iron formulation affects in vitro storage of hops: An image analysis

Summary In vitro-stored plant germplasm is usually evaluated by visual analysis of the plant based on subjective characters. To reduce the variability in these evaluations, we developed a digital-image evaluation system for in vitro-stored plantlets. This study compares the standard visual evaluation system with a digital analysis system to determine if digital analysis can effectively quantify the health of diverse Humulus germplasm. Eight cultivars of Humulus lupulus L. were stored on standard Murashige and Skoog (MS) medium with iron alone (EDTA chelated) and on MS iron with 100 or 200 mgl^−1 sequestrene 138 iron (EDDHA chelated). Digital images of the upper two nodes of each plantlet were evaluated for red, green, blue, green/red ratio, and modified normalized difference vegetation index (MNDVI=R-G/R+G). Evaluation of each plantlet for MNDVI values showed consistent significant differences for all treatments only at the upper node. Significant differences for visual and the MNDVI values among the three iron treatments were observed at the upper node of most of the eight hop cultivars. Regression analysis of the upper node MNDVI values vs. whole-plant visual ratings showed positive correlations for most cultivars. Effects of iron treatments on storage duration were also analyzed for both visual and digital systems. There were significant differences among MNDVI values for plantlets stored on medium with standard MS iron alone (EDTA chelated) and with the addition of sequestrene 138 iron. In general, the MNDVI value of the upper node correlated well with visual ratings and could be used to determine the health of in vitro stored hops.     

Effects of elemental sulphur on the activity of adenylate kinase and performance of isolated rabbit heart

The experiments performed have shown that elemental sulphur inhibited only cytoplasmic isoenzyme of adenylate kinase without having any effect on mitochondrial isoenzyme. Effect of sulphur is related to its reaction with SH-groups of enzyme. Sulphur also by 50% inhibited cytoplasmic adenylate kinase in intact myocardium during perfusion of isolated rabbit heart. Under this circumstances the amplitude of contractions is diminished but perfusate flow is increased. Thus elemental sulphur must be considered as a new specific SH-reagent and vasodilator drug.     

Identification of two outer membrane proteins involved in the oxidation of sulphur compounds in Thiobacillus ferrooxidans

Abstract: Shift of three Thiobacillus ferrooxidans strains from Fe(II) to S⁰ or thiosulphate liquid medium caused distinctive changes in the outer membrane protein profile. In addition to a new 55-kDa protein which was synthesized only in the presence of sulphur compounds, a higher expression of a 47-kDa protein was observed. This latter protein appeared to be constitutively synthesized, since it was detectable in small amounts even in tile presence of ferrous iron as sole energy source, but its expression was greatly enhanced when elemental sulphur or thiosulphate were present in the growth medium.     

Studies on synthetic and structural characterization of new fluorine substituted phthalides of pharmaceutical interest

An efficient and economical synthesis of some new fluorine substituted phthalides was accomplished from two γ-keto acids, 2-(4-fluorobenzoyl)benzoic acid and 2-(3,5-dinitro-4-flurobenzoyl)benzoic acid. Each acid was reacted with various phenolic compounds in presence of catalytic quantity of concentrated sulphuric acid to get the phthalides. The structures of the synthesized compounds were established on the basis of their elemental analysis, spectral data and chemical reactions. Some of the synthesized phthalides exhibited antibacterial and antifungal activity on antimicrobial screening against human pathogenic bacteria and fungi.     

Studies on synthetic and structural characterization of new fluorine substituted phthalides of pharmaceutical interest

An efficient and economical synthesis of some new fluorine substituted phthalides was accomplished from two γ-keto acids, 2-(4-fluorobenzoyl)benzoic acid and 2-(3,5-dinitro-4-flurobenzoyl)benzoic acid. Each acid was reacted with various phenolic compounds in presence of catalytic quantity of concentrated sulphuric acid to get the phthalides. The structures of the synthesized compounds were established on the basis of their elemental analysis, spectral data and chemical reactions. Some of the synthesized phthalides exhibited antibacterial and antifungal activity on antimicrobial screening against human pathogenic bacteria and fungi.     

Microbial oxidation of elemental sulphur in brown soil

Plant and Soil - Brown soil formed from loamy clay was examined for its ability to produce sulphate from added elemental suphur. At higher rates of sulphur applications the pH of a slightly acid...     

Investigation of P and S Distributions in the Roots of Tagetes patula L. using Micro-PIXE

A proton microprobe for energy-dispersive PIXE-analysis hasbeen used to measure elemental distributions of sulphur andother elements in roots of Tagetes patula L. by making a line-scanalong the diameter of the cross-section. Higher concentrationsof phosphorus and sulphur were found in or near the phloem.In addition the endodermis contained an increased sulphur concentration.The results obtained and future possibilities for this kindof investigation are discussed. Key words: Tagetes patula L., micro-PIXE, sulphur, thiophenes, endodermis, Pratylenchus penctrans (Cobb)     

Variation among species in proteomic sulphur content is related to environmental conditions

The elemental composition of proteins influences the quantities of different elements required by organisms. Here, we considered variation in the sulphur content of whole proteomes among 19 Archaea, 122 Eubacteria and 10 eukaryotes whose genomes have been fully sequenced. We found that different species vary greatly in the sulphur content of their proteins, and that average sulphur content of proteomes and genome base composition are related. Forces contributing to variation in proteomic sulphur content appear to operate quite uniformly across the proteins of different species. In particular, the sulphur content of orthologous proteins was frequently correlated with mean proteomic sulphur contents. Among prokaryotes, proteomic sulphur content tended to be greater in anaerobes, relative to non-anaerobes. Thermophiles tended to have lower proteomic sulphur content than non-thermophiles, consistent with the thermolability of cysteine and methionine residues. This work suggests that persistent environmental growth conditions can influence the evolution of elemental composition of whole proteomes in a manner that may have important implications for the amount of sulphur used by living organisms to build proteins. It extends previous studies that demonstrated links between transient changes in environmental conditions and the elemental composition of subsets of proteins expressed under these conditions.     

Sulphur oxidation by soil fungi including some species of mycorrhizae and wood-rotting basidiomycetes

Abstract The mycorrhizal fungi Amanita muscaria, Paxillus involutus, Hymenoscyphus ericae, Pisolithus tinctorius, Rhizopogon roseolus , and Suillus bovinus oxidized elemental sulphur to thiosulphate and sulphate in vitro. In some, but not all cases, tetrathionate was also formed. Limited oxidation of elemental sulphur by R. roseolus also occurred when growing in association with Pinus contorta in unsterilized peat. Although yeasts capable of oxidizing sulphur could not be isolated from a wide range of soils, a yeast-like fungus ( Monilia sp.) isolated from deciduous woodland soil oxidized elemental sulphur to sulphate, forming thiosulphate, but not tetrathionate. This fungus also oxidized tetrathionate to sulphate but showed only limited ability to oxidize thiosulphate to tetrathionate. Both Aspergillus niger and Trichoderma harzianum oxidized elemental sulphur in mixed culture with Mucor flavus . Larger amounts of sulphate were initially formed in mixed, compared to single culture; but by week 5 of the incubation period sulphate formation was greatest in single culture. The wood-rotting fungi, Hypholoma fasciculare and Phanerochaete velutina showed a limited ability to oxidize elemental sulphur in vitro but were incapable of oxidizing the element when growing as mycelial cords in non-sterilized soils. The relevance of these results to the possibility that fungi play a role in sulphur oxidation in soils is commented upon.     

Detection of a [3Fe-4S] cluster intermediate of cytosolic aconitase in yeast expressing iron regulatory protein 1. Insights into the mechanism of Fe-S cluster cycling.

Interconversion of iron regulatory protein 1 (IRP1) with cytosolic aconitase (c-aconitase) occurs via assembly/disassembly of a [4Fe-4S] cluster. Recent evidence implicates oxidants in cluster disassembly. We investigated H(2)O(2)-initiated Fe-S cluster disassembly in c-aconitase expressed in Saccharomyces cerevisiae. A signal for [3Fe-4S] c-aconitase was detected by whole-cell EPR of aerobically grown, aco1 yeast expressing wild-type IRP1 or a S138A-IRP1 mutant (IRP1(S138A)), providing the first direct evidence of a 3Fe intermediate in vivo. Exposure of yeast to H(2)O(2) increased this 3Fe c-aconitase signal up to 5-fold, coincident with inhibition of c-aconitase activity. Untreated yeast expressing IRP1(S138D) or IRP1(S138E), which mimic phosphorylated IRP1, failed to give a 3Fe signal. H(2)O(2) produced a weak 3Fe signal in yeast expressing IRP1(S138D). Yeast expressing IRP1(S138D) or IRP1(S138E) were the most sensitive to inhibition of aconitase-dependent growth by H(2)O(2) and were more responsive to changes in media iron status. Ferricyanide oxidation of anaerobically reconstituted c-aconitase yielded a strong 3Fe EPR signal with wild-type and S138A c-aconitases. Only a weak 3Fe signal was obtained with S138D c-aconitase, and no signal was obtained with S138E c-aconitase. This, paired with loss of c-aconitase activity, strongly argues that the Fe-S clusters of these phosphomimetic c-aconitase mutants undergo more complete disassembly upon oxidation. Our results demonstrate that 3Fe c-aconitase is an intermediate in H(2)O(2)-initiated Fe-S cluster disassembly in vivo and suggest that cluster assembly/disassembly in IRP1 is a dynamic process in aerobically growing yeast. Further, our results support the view that phosphorylation of IRP1 can modulate its response to iron through effects on Fe-S cluster stability and turnover.     

Organoheterotrophe Laugung resistenter Materialien

Leaching processes can be classified in chemolithotrophic and organoheterotrophic mechanisms. In the case of chemolithotrophic leaching sulphide minerals, elemental sulphur, ferrous iron and a number of different reduced metals will be oxidized in a solution containing sulphuric acid of bacterial and/or chemical origin. Organoheterotrophic leaching however is connected with the accumulation of microbial metabolites such as organic acids, proteins, peptides and polysaccharides, which are capable to disintegrate ores, minerals or industrial wastes through dissolution, formation of complexes or chelates. Whereas at the present time chemolithotrophic leaching processes are in operation in industrial scale for the winning of copper, uranium and some other special metals, organoheterotrophic processes, their problems and technical applications are still under study. Therefore problems of organoheterotrophic leaching of chemical high resistant materials such as phosphorus furnace slag and zircon from the Baltic shield have been investigated with regard to possible technical applications for the winning of rare earth elements (REE) and other precious metals. Using a strain of Acetobacter methanolicus which is able to accumulate large amounts of gluconic acid on the basis of glucose or glucose containing by-products, leaching effects up to 90% of REE could be realized in the case of phosphorus furnace slag and up to 45% in the case of zircon.     

Comparison of bioleaching behaviors of different compositional sphalerite using <Emphasis Type="Italic">Leptospirillum ferriphilum</Emphasis>, <Emphasis Type="Italic">Acidithiobacillus ferrooxidans</Emphasis> and <Emphasis Type="Italic">Acidithiobacillus caldus</Emphasis>

Two sphalerite samples with different iron/sulphur (Fe/S) ratios, Shuikousan ore (Fe/S 0.2) and Dachang ore (Fe/S 0.52), were processed using three microbial species, Leptospirillum ferriphilum, Acidithiobacillus ferrooxidans and Acidithiobacillus caldus. Following 20 days of bioleaching in shake flask cultures, a higher zinc (Zn) extraction (96%) was achieved with Shuikousan ore than with Dachange ore (72%). The extraction efficiency increased when elemental S was added to Dachang ore to attain the same Fe/S ratio as that for Shuikousan ore. Following the addition of S, the redox potential, pH and total dissolved Fe for Dachang ore demonstrated similar behaviors to those of Shuikousan ore. Acidithiobacillus caldus and L. ferriphilum became the dominant species during the bioleaching of sphalerite with a high Fe/S ratio. In contrast, the dominant species were A. ferrooxidans and A. caldus during the bioleaching of sphalerite with a low Fe/S ratio. These results show that the Fe/S ratio has a significant influence on the bioleaching behavior of sphalerite and the composition of the microbial community.     

Effect of industrial immissions with high sulphur dioxide content on thiobacilli and oxidative activity of spruce forest soils towards inorganic sulphur compounds

Effect of industrial immissions with high sulphur dioxide content on the upper horizons of spruce forest soils in NW Bohemia was investigated. The content of sulphates, oxidative activity towards sulphide, elemental sulphur, thiosulphate and sulphite, concentration and species representation of thiobacilli in horizons F, H and A in regions highly affected by immissions (two localities) and in regions relatively less influenced (three localities) were followed. In the affected areas the sulphur content in the soil was higher, the species representation of thiobacilli was similar and their concentration was higher, the ability of the soil to oxidize thiosulphate was inhibited and oxidation of elemental sulphur was stimulated. The oxidation of sulphide and sulphite was not significantly affected by the immissions. Changes caused by immissions could be observed only in horizons F and H and did not involve horizons A.