Decomposition of silicate minerals by Bacillus mucilaginosus in liquid culture (original) (raw)
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Chinese Journal of Geochemistry, 2011
Bacillus mucilaginosus is a common soil bacterium, and usually used as a model bacterium in studying microbe-mineral interactions. Several reaction mechanisms of B. mucilaginosus weathering silicate minerals were proposed. However, the molecule mechanisms and detailed processes were still unclear. In this paper, bacterium-mineral interactions were studied in terms of variations in pH value over the experimental period, variations in mineral composition, weathering rates of silicate minerals and volatile metabolites in the culture medium, etc., to further explore the bacterium-mineral interaction mechanisms. The results showed that B. mucilaginosus could enhance silicate mineral weathering obviously. The weathering rates were quite different for various kinds of silicate minerals, and the weathering rate of weathered adamellite could reach 150 mg/m 2 /d. Although B. mucilaginosus produced little acidic substance, pH in the microenvironment of bacterium-mineral complex might be far lower than that of the circumjacent environment; a large amount of acetic acid was found in the metabolites, and was likely to play an important role as a ligand. These results appear to suggest that acidolysis and ligand degradation are the main mechanisms of B. mucilaginosus dissolving silicate minerals, the formation of bacterium-mineral complexes is the necessary condition for the bacteria weathering silicate minerals, and extracelluar polysaccharides played important roles in bacterium-mineral interaction processes by forming bacterium-mineral complexes and maintaining the special physicochemical properties of microenvironment.
Chemical Geology, 2002
Si adsorption onto Bacillus subtilis and Fe and Al oxide coated cells of B. subtilis was measured both as a function of pH and of bacterial concentration in suspension in order to gain insight into the mechanism of association between silica and silicate precipitates and bacterial cell walls. All experiments were conducted in undersaturated solutions with respect to silicate mineral phases in order to isolate the important adsorption reactions from precipitation kinetics effects of bacterial surfaces. The experimental results indicate that there is little association between aqueous Si and the bacterial surface, even under low pH conditions where most of the organic acid functional groups that are present on the bacterial surface are fully protonated and neutrally charged. Conversely, Fe and Al oxide coated bacteria, and Fe oxide precipitates only, all bind significant concentrations of aqueous Si over a wide range of pH conditions. Our results are consistent with those of w Ž .
Laboratory evidence for microbially mediated silicate mineral dissolution in nature
Chemical Geology, 1996
Bacteria may potentially enhance or inhibit silicate mineral dissolution in nature by a variety of mechanisms. In the laboratory, some micrc,bial metabolites enhanced dissolution rates by a factor of ten above the expected proton-promoted rate by an additional ligand-promoted mechanism focussed principally at A1 sites at the mineral surface. In investigations with bacteria, it was found that organic acids are produced in organic-rich/nutrient-poor cultures, resulting in increased mineral dissolution rates compared to abiotic controls. Alginate and poly-aspartate inhibited dissolution rates either by a reduction in surface reactivity or reactive surface area (or both). Bacteria may also influence dissolution rates by creating and maintaining microenvironments where metabolite concentrations are higher than in the bulk solution.
Ceramics Silikaty
Dissolution of aluminosilicates and Fe-oxyhydroxide minerals from granitic eluvium using bacteria of Bacillus genus was monitored with solution chemistry, granulometric and X-ray analyses as well as microscopic techniques to determine the effects of these bacteria on crystal surface and releasing mechanism of K, Si, Fe, and Al from minerals. Feldspars, quartz and micas are dominant minerals in granitic eluvium (GE). Oxyhydroxides of Fe are found in the intergranular spaces of minerals, contaminating and making most feldspar raw materials unsuitable for commercial applications. Bacteria of Bacillus spp. decrease pH of leaching medium by production of organic acids. These organic acids are directed by glycocalyx of adherent bacteria to specific sites on mineral surface (e.g. to crystal defects). The impregnated iron minerals are released by bacterial destruction of intergranular and cleavage spaces of silicate grains. This bacterial activity results in the release of Fe, Si, and K fro...
Vietnam Journal of Biotechnology, 2020
Silicate solubilizing bacteria (SSB) are key microorganisms to solubilize silicate minerals in the soil. Silicon helps to increase the growth and yield of plants and to enhance the environmental stress tolerance capability of plants. The aim of this study was to evaluate the effect of several factors like pH, salinity, and temperature on silicate solubilizing capacity of five selected SSB. Moreover, phosphorus solubilizing, nitrogen-fixing and indole-3-acetic acid (IAA) synthesizing capacity of these five bacteria were also tested. Liquid soil extract medium containing 0.25% Mg2O8Si3 was used in this study. Abilities of bacteria in phosphorous solubility, nitrogen fixation, and IAA synthesis were tested in NBRIP, Burk’s and NBRIP containing 100 mg L-1 tryptophan media, respectively. The results of the study indicated that five SSB showed their high capacity in silicate solubilization at pH 7.0, NaCl 0.0% and 35oC. However, at a concentration of NaCl 0.5%, these five SSB still solubi...
Silicates, Silicate Weathering, and Microbial Ecology
Geomicrobiology Journal, 2001
Mineralogy, microbial ecology, and mineral weathering in the subsurface are an intimately linked biogeochemical system. Although bacteria have been implicated indirectly in the accelerated weathering of minerals, it is not clear if this interaction is simply the coincidental result of microbial metabolism, or if it represents a speci c strategy offering the colonizing bacteria a competitive ecological advantage. Our studies provide evidence that silicate weathering by bacteria is sometimes driven by the nutrient requirements of the microbial consortium, and therefore depends on the trace nutrient content of each aquifer mineral. This occurrence was observed in reducing groundwaters where carbon is abundan t but phosphate is scarce; here, even resistant feldspars are weathered rapidly. This suggests that the progression of mineral weathering may be in uenced by a mineral's nutritional potential, with microorganisms destroying only bene cial minerals. The rock record, therefore, may contain a remnant mineralogy that re ects early microbial destruction of biologically valuable minerals, leaving a residuum of "useless" minerals, where "value" depends on the organism, its metabolic needs, and the diagenetic environment. Conversely, the subsurface distribution of microorganisms may, in part, be controlled by the mineralogy and by the ability of an organism to take advantage of mineral-bound nutrients.
Mineralogy and Petrology, 2012
The bio-weathering of basalt, granite and gneiss was experimentally investigated in this study. These rockforming 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.
Some microbiological aspects of bauxite mineralization and beneficiation
Mining, Metallurgy & Exploration, 1997
A microbial survey of Jamnagar bauxite mines in Gujarat, India, revealed the indigenous presence of a variety ofautotrophic and heterotrophic bacteria andfungi associated with the ore body and water ponds in the vicinity. Among these, bacteria belonging to the genera Thiobacillus, Bacillus and Pseudomonas are implicated in the weathering ofaluminosilicates; the precipitation ofiron oxyhydroxides; the dissolution and conversion ofalkaline metal species; and the formation ofalumina, silica and calcite minerals. Fungi belonging to the genus Cladosporium can reduce ferric iron and dissolve alumina silicates. Biogenesis thus plays a significant role in bauxite mineralization. Various types of bacteria and fungi, such as Bacillus polymyxa, Bacillus coagulans and Aspergillus niger, were found to be efficient in significant calcium solubilization and partial iron removal from bauxite ore. Probable mechanisms in the biobeneficiation process are analyzed. Biobeneficiation is shown to be an effective technique for the removal ofiron and calcium from bauxite ores for use in refractories and ceramics.
Interaction of microorganisms with sheet silicates
2013
To study the interaction between microorganisms and sheet silicates, nontronite (NAu-2), and chlinochlore (CCa-2) as a powder form less than 2 µm were incubated with two microorganisms; Streptomyces acidiscabies and Schizophyllum commune strains in liquid culture flasks for two months. CCa-2 is a non swelling mineral, while NAu-2 is a swelling mineral, where hydrated ions incorporate into the mineral interlayer. Consequently, the mineral expands and additional mineral surfaces are more exposed to solution and microbial attack. That is why NAu-2 was more susceptible to microbial dissolution than the CCa-2. X-ray diffraction (XRD) spectra showed that there was no change at all in the structure of CCa-2, while NAu-2 became amorphous to X-rays. S. acidiscabies E13 strain produces some organic acids, exo- polysaccharides (EPS), enzymes, siderophores, and melanin. The production of some of these biomolecules together at the same time might be the main reason that the S. acidiscabies strai...