[en] The paper investigates the role of the sulfur-oxidizing bacteria Thiobacillus thiooxidans in pyrite weathering in order to clarify the effects of the bacteria on the dissolution behavior of pyrite and the formation of secondary minerals using Raman spectroscopy and powder X-ray diffraction (XRD) in addition to solution analysis. It was found that T. thiooxidans, when present with the iron-oxidizing bacteria Thiobacillus ferrooxidans, enhanced the dissolution of Fe and S species for pyrite, whereas T. thiooxidans alone did not oxidize pyrite. Enhancement of the consumption of elemental sulfur and regeneration of Fe(II) ions were also observed with T. thiooxidans together with T. ferrooxidans, while this did not occur with T. ferrooxidans alone

[en] It is known that microbes obtained in the rock having sulfur and uranium have the highly ability in extraciting uranium (21-24 %). An experiment was carried out in the leaching process using those microbes and T. ferrooxodans 402 which has the capability in extracting uranium on 28 %. Four combination treatments has been done in this research using ATCC suspension for the medium of microbes as well as the solution for the process. From the data obtained, the extracting ability of microbe for uranium shows no statistical significant difference between treatments. Generally, the combination treatment tends to decrease the capability of uranium extraction which being possessed by the microbe. The highly yield uranium extraction was found on the combination treatment used TP-4/1 with CB-17/3, T.ferrooxidans 10435, or with T. ferrooxidans 402, while other treatment only gave yield around 6 to 10 % uranium. (authors). 11 refs, 2 figs, 4 tabs

[en] Biotechnology is regarded as one of the most promising and revolutionary solution to various problems which are generally faced in the extraction of metals from their ores such as high energy, capital costs and environmental pollution. The paper deals with the study of low grade copper ores for their beneficiation and extraction of copper. The ores used were chalcopyrite and oxidized copper ores. Microorganisms play a vital role in the solubilization of valuable contents from ores such as copper and other metals. Studies have been conducted on the indigenous copper ores by using thiobacillus ferro oxidans and thiobacillus thio oxidans. For comparison purpose some experiments have also been conducted by chemical leaching. The results of bacterial leaching are encouraging. (author)

[en] The performance of Cytisus striatus in association with different microbial inoculant treatments on the dissipation of the insecticide hexachlorocyclohexane (HCH) was studied. Two soils with different organic matter (A and B soil) content were spiked with 0 or 65 mg HCH kg⁻¹. Plants were either not inoculated (NI), or inoculated with the endophyte Rhodococcus erythropolis ET54b and the HCH-degrader Sphingomonas sp. D4 separately or in combination (ET, D4 and ETD4). Unplanted pots were also established. HCH phytotoxicity was more pronounced in the B soil. Soil HCH concentrations in unplanted pots were similar to initial concentrations, whereas concentrations were reduced after plant growth: by 20% and 8% in A and B soil, respectively. Microbial inoculants also modified HCH dissipation, although effects were soil-dependent. Inoculation with the combination of strains (ETD4) led to a significant enhancement in HCH dissipation: up to 53% in the A soil and 43% in the B soil. -- Highlights: •Effect of microbial inoculants on HCH dissipation was studied in a plant-soil system. •Inoculation of C. striatus with bacterial strains strongly enhance HCH dissipation. •Retention of HCH by organic matter can influence efficiency of HCH phytoremediation. -- The inoculation of Cytisus striatus with a combination of bacterial strains is a promising approach for the remediation of HCH-contaminated sites

[en] 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)

[en] The objective of this experiment was to investigate the possibility of using microbe other than Thiobacili to leach U from the low grade ores. Microbe used in this experiment was isolated from the rock containing sulfur.This microbe was not yet being identified strickly, in spite of that the colony coloured was cream on the anorganic solid medium, punctiform, gram negative and the cell measured as 0.7 x 1.0 u. The addition of exp.2, exp.4, and exp.6 microbe/ml into this process which was using 2 various solution (9 K and H2SO4) with the difference pH (1.5 and 2.5), obviously gave no response to the increasing of uranium being extracted. Nevertheless, the indirect effect of these three interaction factors can be seen on the changing of pH, redox potential, ferrous ion and Fe total which effective the uranium being extracted. The percolation method tend to be higher in the extracting uranium compared with the shaking method. In the percolating method, the edition of exp.4 microbe/ml at the beginning of experiment tend to increase the production of uranium being extracted, while for the shaking method required exp.6 microbe/ml to be added, although, statistically there is no significant difference compared with control. (author). 9 refs, 6 tabs

[en] To explore plate separation techniques of Acidithiobacillus ferrooxidans and understand its growth characteristic, strains of Acidithiobacillus ferrooxidans were obtained by separation and purification using 2 : 2 solid medium. And growth characteristics of 5 strains of them were studied. The results showed that 2 : 2 solid medium could be used ideally for separation and purification of Acidithiobacillus ferrooxidans. And the fastest growth rate of Acidithiobacillus ferrooxidans could get at the initial pH value from 2.O to 2.5, the optimal growth temperature was 30 ℃ 9 the initial Fe²⁺ concentration might be desirable for 4.623 g/L, and the appropriate inoculums' quantity was 10%. There existed growth characteristics differences among different Acidithiobacillus ferrooxidans strains. (authors)

[en] The present development, including development of new leaching processes and equipment and soon, in bacteria leaching of uranium and gold ores at home and abroad are described. Opinions and advices are presented

[en] During solubilization processes of low grade sulphidic ores, the auto trophic bacteria oxidize reduced sulphur compounds and ferrous iron to sulphates and ferric iron respectively. The ore leaching bio topes are not only colonized by auto trophic bacteria (Thiobacillus spp., Leptospirillum ferro oxidans and sulfolobus sp.) but the heterotrophic microorganisms, including bacteria and fungi of various species are also found in these habitats. The autotrophs, in addition to energy metabolism, also produce organic compounds which in excess amount inhibit their growth. Through the utilization of such compounds and also through the production of carbon dioxide and ammonia, these heterotorphs can help bio leaching processes. Effect of one of the heterotrophs; methylobacterium sp., a nitrogen scavenger, found in as association with the thio bacilli in one of the leaching bio tope in Germany was studied in leaching of a carbonate bearing complex (containing copper, iron, zinc and lead) sulphidic ore, in shake flask studies. T. ferro oxidans (Strain F-40) reported to be non nitrogen fixer and strain F-41, a nitrogen fixing thiobacillus were studied for leachability behaviour alone and in combination with T. thio oxidans (lacking nitrogen fixing ability) using media with and without added ammonium nitrogen. In addition the effect of methylobacterium sp. (alt-25) was also tested with the afore mentioned combinations. Nitrogen fixation by T. ferro oxidans did not suffice the nitrogen requirement and the leaching system in laboratory needed addition of nitrogen. The heterotrophic nitrogen scavenger also did not have a positive influence in nitrogen limited system. In case where ammonium nitrogen was also provided in the media, this heterotroph had a negative in own growth and leaving lesser amount available for thio bacilli. This high amount of acid is a limiting factor in bio leaching of high carbonate uranium ores. Uranium ore ecosystems have also been found to contain association of auto trophic and heterotropic microorganisms. Use of some heterotrophs for production of sufficient acid from molasses for pretreatment of uranium ore has also been discussed. (author)

[en] A secure energy supply is one of the basic pre-requisites for a sound economic system, sustained standard and quality of life and eventually for the social well-being of each individual. For a progressive country like Pakistan, it is obligatory that all energy options must be pursued vigorously including coal utilization, which given the relatively large resources available, is considered to be one of the major options for the next few hundred years. Bioprocessing of coal in an emerging technology which has started to receive considerable research attention. Recent research activities involving coal cleaning, direct coal conversion, and indirect conversion of coal-derived materials have generated a plethora of facts regarding biochemistry, chemistry, and thermodynamic behavior of coal, in that its bioprocessing is on the verge of becoming and acceptable means to great coals. In this research report, investigations pertaining to the various aspects of coal bio processing, including desulfurization and depyritization are discussed. Bituminous coals varying in total sulfur contents of 3-6% were depyritized more than 90% by mesophilic acidophiles like Thiobacillus ferroxidans and Thiobacillus thio oxidans and thermophilic Sulfolobus brierleyi. The archaebacterium, Sulfolobus brierleyi was found to desulfurize inorganic and organic sulfur components of the coal. Conditions were established under which it can remove more than 30% of the organic sulfur present in the coals. Heterotrophic microorganisms including oxenic and soil isolates were also employed for studying sulfurization. A soil isolate, Oil-2, was found to remove more than 70% dibenzothiophenic sulfur present in an oil-water emulsion (1:20 ratio). Pseudomonas putida and the bacterium oil-2 also remove 60-70% organic sulfur present in the shale-oil. Preliminary results indicate the presence of putatively known Kodama's pathway in the oil-2. The mass balance for sulfate indicated the possibility of the presence of 4-S degradative pathway in this bacterium. (author)