• Luis A. Salcedo Mejía added an answer:
    When using heap leach or stirred tank bioreactors, does it depend on the mineral to use?
    There are many processes / patents using bioleaching of sulphide ores or oxidized copper / gold, using both batteries as bioreactors, but this will depend on that? The percentage of precious metal law?
    Luis A. Salcedo Mejía · Universidad Nacional Federico Villareal

    thank yous for all.
    very much thanks you

  • Luis A. Salcedo Mejía added an answer:
    Why can't Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans grow successfully in inorganic solid medium (as 9K, TK, etc.)?
    In liquid cultures with inorganic ferrous sulfate At. ferrooxidans and L. ferrooxidans grow fine but when trying to isolate on solid medium which is growing successfully At. ferrooxidans and L. ferrooxidans show no reproducible sporadic growth.
    Luis A. Salcedo Mejía · Universidad Nacional Federico Villareal
    thank you very much Xavier.
    And could consider a response to genomic level, differences between the genomes of these two species can suggest changes in microbiological assays.
    L. ferrooxidans suggests as being the predominant organism on At. ferrooxidans bioleaching processes.

    best regards
  • Fereydoun Hosseinzadeh added an answer:
    Can we enrich uranium through a process of bioleaching? How?
    Methods and any other ideas are welcome.
    Fereydoun Hosseinzadeh · National Institute of Genetic Engineering and Biotechnology
    Mr Sebtain Afzal
    Thanks alot for this articles
  • Lala Behari Sukla added an answer:
    Is it possible to suggest new approaches for evaluating wastes?
    The waste problem has increased considerably with rapidly increasing population and improvement at industry by developing technology. It is necessary to evaluate the wastes by recovering metals(valuable) from these wastes. Main target of waste management is to detoxify these materials for environmentally safe deposition.
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    Plasma gasification has become a buzzword and the new kid on the waste to energy block. One company has trialled its new process in Mexico, known as microwave plasma gasification, and is starting work on its first commercial facility in Texas. Tom Freyberg investigates claims that the process is 60% more efficient and can produce diesel from waste
  • Lala Behari Sukla added an answer:
    What are the new challenges in the use of sea water in bioprocess industries?
    We may face shortage of water in bioprocess industries. Sea water may be the real alternative.The high costs associated with transportation and desalination may be the real issue.
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    A number of ocean labs, scientists and businesses are exploring fertilization as a means to sequester atmospheric carbon dioxide in the deep ocean, and to increase marine biological productivity which is likely in decline as a result of climate change.
  • Mihail Iliev added an answer:
    Are there promising prospects for recovering heavy metals using microbes?
    Bioleaching to recover metal from waste is simpler, and therefore cheaper to operate and maintain. Fewer specialists are required to operate a complex chemical plant/factory.
    Mihail Iliev · Sofia University "St. Kliment Ohridski"
    Check one of the top scientist in this field - Groudev, S.N.
  • Lala Behari Sukla added an answer:
    Can anyone give me an idea regarding pressure oxidation of chalcopyrite?
    A chalcopyrite based ore if autoclaved in MSM media at neutral pH, can it be oxidized? if yes then to what extent?
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    The smaller the ore granularity, the higher the chalcopyrite leaching rate, so the ores are milled fully before the experiment..Firstly, O2 diffuses into water from the gas/liquid
    interface and then diffuses furthermore. It participates in reaction after it touches the ore surface. It is known that the influence of O2 on the chemical reaction is dependent
    on each O2 diffusible step during the above process. The gas solubility in the water is affected by the temperature and p(O2). The pressure of O2 has direct proportion to the
    O2 concentration in the water. Enhancing p(O2) promotes the O2 solubility and the oxidation speed is increased
  • Iveta Styriaková added an answer:
    In bioleaching application (the releasing of metals from raw material) will fungi or heterotrophic bacteria have better utilization?
    I think fungi produce many allergens and mycotoxins. That is why I have an interest in heterotrophic bacteria.
    Iveta Styriaková · Slovak Academy of Sciences
    Dear Debabrata, it is important fact which I will consider during laboratory experiment. Dear Lala, I often use Bacillus in my bioleaching experiments and I am very satisfied with bacterial activities in the bioleaching of black shale.
  • Lala Behari Sukla added an answer:
    Can anyone suggest current and future trends in using modified microorganisms?
    This is an enormous topic and one of great complexity. Genetic modification means artificially changing the genetic material of an organism. The term genetic modification and genetic engineering are interchangeable. Genes can be moved between species, and between different levels of biological microorganism.
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    When microorganisms are isolated from nature, their performance in producing desired products is rather poor. Metabolic engineering is performed to improve the metabolic and cellular characteristics to achieve enhanced production of desired product at high yield and productivity. Since the performance of microbial cell factory is very important in lowering the overall production cost of the bioprocess, many different strategies and tools have been developed for the metabolic engineering of microorganisms.
  • Lala Behari Sukla added an answer:
    What are the challenges in developing microbial process for recovering metals from oxidic ores?
    Treating oxidic ores through bioleaching process is a great challenge for microbiologists and engineers.
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    Bioleaching is a profitable alternative to the conventional chemical process of uranium recovery. The leaching of U from low-grade ores and solid wastes is realized by chemoautotrophic bacteria such as Acidithibacillus ferrooxidans. Uranium reducing bacteria, particularly Shewanella putrefaciens and Shewanella oneidensis, can be used for UO2 particles synthesis. The bioreduction of U(VI) in the presence of hematite particles can be a way to new catalyst fabrication. (Physicochem. Probl. Miner. Process. 49(1), 2013, 71−79 )
  • Development and application of genetically modified biosurfactants?
    Biosurfactants have gained importance against chemical surfactants because they can be produced from renewable resources using green chemistry. Another important feature is that they are biodegradable and nontoxic. In spite of many laboratory based success in biosurfactants production and its immense commercial applications, the production of biosurfactants at a plant scale remains a challenging issue as the composition of final product is affected by the nutrient, micronutrient, and environmental factors. It is important to formulate the guidelines and regulations to use biosurfactants in different sectors. Super-active microbial strains needs to be developed using genetic engineering for production of biosurfactants at industrial level using renewable substrates as raw material.
    Luis Roberto Rivera-Mackintosh · Autonomous University of Chihuahua
    GM strains are certainly a valid approach, but it depends on the specific type of biosurfactant. For certain biosurfactants, like lipopeptides, there's an untapped research line in solid state cultures.
  • Sandeep Panda added an answer:
    Why do we often face problematic issues in scaling up of microbial cultures?
    When we culture microorganisms in lab scale we get results with efficiency. However, when such microbial cultures are aimed for scaling up for an industrial application (may be in diverse fields) we face a lot problems. How can these issues be resolved? What care should be taken?
    Sandeep Panda · Institute of Minerals and Materials Technology
    I have worked in an industrial heap bioleaching operation. Now interestingly, as everyone has discussed, it is indeed a great problem when we scale up. As in my case where bacterial solution is prepared at once in some cubic meters in open bioreactors under natural environmental conditions, the volume is affected by evaporation losses which has to be daily monitored and compensated with appropriate water or media. Also homogenity is a issue. Still we have tried to minimize the problems and are still working on to provide an easy and faster way to recover metal values using microbial biotechnology.
  • Lala Behari Sukla added an answer:
    Can bioinformatic predictions play an important role in application of bioleaching process on an industrial scale?
    Bioinformatics information towards bioleaching.
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    With about 300 fully sequenced bacterial and archaeal genomes and with additional information of hundreds of thousands of DNA and protein sequences in public databases it is possible to predict genes and their putative protein products in DNA sequences derived from genome sequencing projects. In this chapter, it provides a general overview of how bioinformatics and genome biology can provide insight into the genomic organization and function of biomining microorganisms with a special reference to Acidithiobacillus ferrooxidans about which most is known. Bioinformatics and genome biology are effective tools for making preliminary inroads into how an otherwise uncharacterized organism functions. It is particularly powerful in cases where it is difficult to implement conventional genetic tools such as in the case of several bioleaching microorganisms and results are beginning to emerge to support this view
    The Use of Bioinformatics and Genome Biology to Advance Our Understanding of Bioleaching Microorganisms
    Chapter in book “Microbial processing of metal sulphides”, eds. W. Sand and E. Donati. Springer (accepted).
  • Lala Behari Sukla added an answer:
    Latest information on chalcopyrite heap bioleaching?
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    You can refer the paper Advances in high-temperature heap leaching of refractory copper sulphide ores,SW Robertson, PJ van Staden, A Seyedbagheri,journal of African
    instutute.min metall,vol-112,no-12,2012
  • Lala Behari Sukla added an answer:
    Can anyone give a possible idea related to the use of iron reducing bacteria (IRB) for chalcopyrite processing or leaching
    Lala Behari Sukla · Council of Scientific and Industrial Research (CSIR), New Delhi
    The number of biotechnological applications of IRB, including remediation of soils and sediments contaminated with metals, radionuclides and organics, is rapidly increasing.Bioleaching of iron from kaolin using Fe(III) reducing bacteria has been studied.Nickel present in goethite has been released using IRB in case lateritic ore. A lot of progress has been made towards understanding of the phylogeny, ecology and biogeochemical role of dissimilatory iron-reducing bacteria. The known phylogenetic range of iron-reducing bacteria has expanded considerably, as has the known range of iron minerals that serve as a source of Fe(III) for anaerobic respiration. You can try IRB for processing of Chalcopyrite.I think IRB may break the Chalcopyrite structure and help in releasing copper into solution.

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