The presence of radionuclides and heavy metals in our surroundings has become the most serious environmental concern. These contaminants or pollutants fail to degrade on their own over time and must be removed or neutralized. Microorganisms act as natural catalysts in the process of transformation of toxic metals into non-toxic ones. This is why there is an increased interest in the understanding of microbiological processes which help in remediation of these toxic wastes from the environment (Francis 1990).
Microorganisms basically work by mobilization and immobilization of heavy metals and radioactive wastes. Mobilization include processes such as methylation of wastes and thus making them volatile substances, chelation of metals to
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This product is also found to be readily acted upon by a variety of degrading bacteria, algal species and fungal species also (Gadd 1996), (Karlson et al. 1993).
b) Autotrophic Leaching:
The chemolithic and acidophilic bacteria help in carrying out the autotrophic leaching of metals. They function by fixing carbon-di-oxide and obtaining energy from the oxidation of ferrous ions or reduced sulphur compounds, and form Fe(III) or H2SO4 as the end products (Bosecker 1997). The microorganisms involved in this process are Thiobacillus thioxidans, Thiobacillus ferroxidans, Leptospirillum ferroxidans (Ewart and Hughes 1991).
Also the production of sulphuric acid by Thiobacillus species is a form of bioremediation of sewage wastes. This technique has been used to remediate the problems of heavy metal contaminated soil, water, sewage etc.
c) Heterotrophic Leaching:
Heterotrophic metabolism can also account for leaching as it can cause the release of proton or organic acids (Burgstaller and Schinner 1993). For eg., Uranium reacts with chelating anion like citrate and form very stable Uranium- citrate complexes (Borkowski et al. 1997).
Now, many microorganisms such as bacteria or fungi are able to act upon these metal-chelate complexes and thus form products which are non- toxic to environment.
3.1.2 Metal
Deinococcus radiodurans is a member of the bacteria kingdom, belonging to the phylum Deinococcus-Thermus, and more specifically, the Deinococus genus. It is spherical in shape, and approximately 1.5 to 3.5 µm in diameter. It is usually found in tetrad formation: where four individual cells stick together. D. radiodurans isn 't known the cause any diseases, nor does it form endospores, and it stains gram positive. It is non-motile, and an obligate aerobic chemoorganoheterotroph. What makes D. radiodurans so unique, is its ability to withstand ionizing radiation, UV light, desiccation, and even oxidizing and reducing agents. When D. radiodurans was first discovered in 1956 by Arthur Anderson, it showed only a fraction of its amazing survivability. While Anderson was performing experiments to determine if canned food could be purified when exposed to high doses of gamma radiation: the meat still spoiled and from it D. radiodurans was isolated. Due to the fact that D. radiodurans can survive in such toxic situations, and that it is found in a wide variety of environments, scientists have long been toying with the idea of using D. radiodurans for bioremediation.
The experiment shows that bleach is an effective way of reducing some bacteria, but enough for a significant difference. Further testing is required to see if bleach alone could be used to eliminate all bacterial colonies. Introduction Phosphorous is a crucial element to all life on Earth. It is found in water, soil,
Before one of my father's greatest friends had died, he told about the story of my parents and how they became part of the Lakota tribe. My father had died without a chance to finish his journal so I have taken it into my hands to finish the journal. As far as I'm concerned, being the eldest means I've know more about his life experience than the others.
Prokaryotes are ubiquitous, successfully adapting to diverse environments as well as developing symbiotic relationships with host organisms (Lengeler, Drews, & Schlegel, 1999). Prokaryotes may have both autotrophic and heterotrophic characteristics. A cyanobacteria is photosynthetic, commonly called blue-green algae, and may produce toxins (Crayton, 1993). Bacteria are most commonly associated in the general
Vincent Van Gogh’s created a variety of artwork that featured objects in their natural setting. Van Gogh used elements to captivate what is shown. Cafe Terrace at Night is a painting that uses the medium of oil on canvas. Within the artwork, organic shapes form the intricate objects in this piece, to create the bigger picture. There are geometric shapes within objects such as ovals, squares, and rectangles. Tables that appear farther away lack detail from those closer to the front. The buildings are angled on the horizon, creating a street view perspective. In this piece, there is only a single vanishing point. Lines on the street directly point to the center of the piece, which shows a horse and carriage. Shutters and electrical lines are
Ideal culture conditions are acidic pH and high temperatures because S. acidocaldarius is an aerobic thermophile found in hot springs, such as Yellowstone National Park (Rice et al., 2001). This bacterium grows on complex organic substrates, such as yeast and some amino acids. The primary responsibility of this bacterium is to metabolize sulfur (Chen et
Ralstonia eutropha (R. eutropha) is a gram negative rod shaped (bacillus) bacteria which is catalase and oxidase positive (Yabuuchi et al, 1995) hence is a facultative anaerobe. R. eutropha has gone through a number of name changes including Hydrogenomonas eutrophus and Alcaligenes eutropha (Yabuuchi et al, 1995 and Repaske and Mayer 1976). It can be found in both fresh water and soil and is incredibly versatile as it can exist on only hydrogen (H2) and carbon dioxide (CO2) as an energy and carbon source (Pohlmann et al, 2006). Due to this versatility, R. eutropha has a number of beneficial uses.
During bioremediation, microbes consume contaminants, transforming them into small quantities of water and harmless gas (ex. carbon dioxide). Some microbes are aerobic while others are anaerobic. (EPA, 2013). Microbes absorb oil, oxygen and nutrients and release gases and water. “Bioaugmentation” is the process where microbes are added to soil and groundwater that do not have enough. The optimal temperature, nutrients and food must be present for bioremediation to occur. Suitable conditions allow the microbes to grow, multiply and consume more contaminants. If the conditions are not up to standard, the microbes grow too slow or die before the contaminants are cleaned up. These conditions can be improved by adding “amendments”. (EPA, 2015).
Bioreactors are employed when the value of the gold recovery is sufficient to justify the costs of installing and operating the necessary equipment. Bioreactors are able to process less gold ore at one time, but create a much faster oxidation process. This process usually utilizes higher grade ores compared to heap leaching. This type of bioleaching is characterized by a reactor tank in which relatively finely ground ore and nutrients are added, as well as bacteria containing solution to create a slurry (Figure 1). This mixture is then mechanically or air agitated.
Who I am is made up from several aspects of my life and how I’ve developed over the years. Ever since I was younger, I was ambitious and tried to work my hardest to make everyone around of me proud. Of course, what third grader wouldn’t want to be praised? My elementary years were a breeze to me; I didn’t worry about making friends because it came naturally to me, I was in several advanced programs, and I made my parents happy, so everything felt amazing to me.
Among the bacteria, Yersinia enterocolitica deposited elemental bismuth during the exponential phase of growth [28]. The anaerobic bacterium C. acetobutylicum was found to be able to produce hexagonally shaped Bi2S3 nanostructures with the average size of 440–500 nm [16]. Nazari et al. [5] isolated a marine Gram-negative bacterial species (S. marcescens) capable to form Bi NPs with the average particle size of 150 nm. The ability of bacterial strains of Delftia family like D. acidovorans for reduction of Au3+ ions to Au0 has been previously reported [29]. It was showed that D. acidovorans was able to increase its survival in the presence of toxic Au3+ ions by secreting delftibactin which facilitates the reduction of Au3+ ions to less toxic elemental Au0 nanoparticles [29].
The contamination has affected the marine population at large but few of bacteria have found way out to tolerate such high concentration of mercury. Such bacteria have been discovered way back in 1960’s by Moore, where he reported to found an operon called as mercury operon or mer operon which is found to be integrated on plasmid, transposons, etc., which harbors the efficiency to withstand mercury contamination. Further various researches were made and it was found that mer operon primarily have two genes called merA which encodes for mercury reductase enzyme which breaks down inorganic form of mercury (Hg2+) to less toxic and volatile form of mercury (Hg0), which is released in environment and the other gene called merB which acts on organic form of mercury (CH3Hg+) to convert it into Hg2+.Thus two major mechanisms are found to be associated with mercury
Daims and colleagues (2015) initiated the study in Aushiger, Russia in April 2011, following the sampling of a microbial biofilm situated on a metal pipe constantly under the flow of hot water, from a 1200 meter deep oil exploration well. Using the biofilm as an inoculum, it was incubated at 46⁰ C in an ammonium-containing mineral medium for the enrichment of moderately thermophilic ammonia-oxidizing microbes. Following several serial dilutions in a similar AOM medium, the enrichment culture ENR4 was cultivated. The ENR4 culture was now scaled up to obtain enough biomass for DNA extraction, and various other analyses including phase contrast microscopy, electron microscopy, FISH, PCR and metagenomics.
Cadmium and cadmium compounds are, compared to other heavy metals, relatively water soluble and mobile compound in most soils, generally more bio- available and tends to bio- accumulate. It induces cell injury and death by interfering with calcium (Ca) regulation in biological system. Cadmium is not essential for plant or animal life (IPCS monographs/WHO1995a; WHO1995b). It is more mobile than zinc but less mobile than nickel. Cadmium is readily accumulated by many organisms, particularly by microorganism and mollusks where the bio-concentration factors are in the order of thousands. Its mobility essentially depends on the pH; the metal’s adsorption to the soil’s solid phase can be multiplied threefold for every unitary increase in pH in a range from 4 to 8. Terrestrial plants may accumulate cadmium in the roots and cadmium is found bound to the cell walls (AMAP 2002). The pH level is one of the most important factors controlling cadmium absorption. Compared with other micropolluants such as Cu or Pb, transfer of Cd to the above ground parts of the plant may be considered as
Pollution is one of the world’s leading problems. One contributing pollutant is plastic. One such pollutant is plastic; which contributes to 40% of the oceans surfaces being contaminated, and makes up 10% of the overall waste produced by humans (D’Alessandro). This problem of accumulating plastic waste gradually increases with time as all plastic that has ever been produced is still around in one way or another; for plastic takes between 450-1000 year to decompose ( Roth). Thankfully the solution is a fungus. The process that should be used to break down plastic in mass quantities is fungi mutarium.