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  1. Yadzir, Z.H.M., Gafar, A.A., Rahman, M.F., Yakasai, M.H., Abdullah, M.A., Shamaan, N.A., et al.
    MyJurnal
    Contamination of organic xenobiotic pollutants and heavy metals in a contaminated site allows
    the use of multiple bacterial degraders or bacteria with the ability to detoxify numerous toxicants
    at the same time. A previously isolated SDS- degrading bacterium, Acinetobacter baumannii
    strain Serdang 1 was shown to reduce molybdenum to molybdenum-blue. The bacterium works
    optimally at pH 6.5, the temperature range between 25 and 34°C with glucose serves as the best
    electron donor for molybdate reduction. This bacterium required additional concentration of
    phosphate at 5.0 mM and molybdate between 15 and 25 mM. The absorption spectrum of the
    molybdenum blue obtained is similar to the molybdenum blue from other earlier reported
    molybdate reducing bacteria, as it resembles a reduced phosphomolybdate closely. Ag(i), As(v),
    Pb(ii) and Cu(ii) inhibited molybdenum reduction by 57.3, 36.8, 27.7 and 10.9%, respectively, at
    1 p.p.m. Acrylamide was efficiently shown to support molybdenum reduction at a lower
    efficiency than glucose. Phenol, acrylamide and propionamide could support the growth of this
    bacterium independently of molybdenum reduction. This bacterium capability to detoxify several
    toxicants is an important tool for bioremediation in the tropical region.
  2. Othman, A.R., Rahman, M.F., Shukor, M.Y., Abu Zeid, I.M., Ariffin, F.
    MyJurnal
    Chemical toxins and organic contaminants such as hydrocarbons and dyes are major global
    contaminants with countless tones of those chemicals are created yearly with a significant
    amount release to the environment. In this work we screen the ability of a molybdenum-reducing
    bacterium isolated from contaminated soil to decolorize various azo and triphenyl methane dyes
    independent of molybdenum reduction. Biochemical analysis resulted in a tentative identification
    of the bacterium as Enterobacter sp. strain Zeid-6. The bacterium was able to decolorize the azo
    dye Orange G. The bacterium reduces molybdate to Mo-blue optimally at pH between 5.5 and
    8.0 and temperatures of between 30 and 37 oC. Other requirements include a phosphate
    concentration of 5 mM and a molybdate concentration of 20 mM. The absorption spectrum of the
    Mo-blue produced was similar to previous Mo-reducing bacterium, and closely resembles a
    reduced phosphomolybdate. Molybdenum reduction was inhibited by copper, lead, mercury and
    silver which showed 36.8, 16.9, 64.9 and 67.6% inhibition to Mo-reducing activity of
    Enterobacter sp. strain Zeid-6, respectively. The resultant molybdenum blue spectrum closely
    resembles the spectrum of molybdenum blue from the phosphate determination method. The
    ability of this bacterium to detoxify molybdenum and decolorize azo dye makes this bacterium
    an important tool for bioremediation.
  3. Abo-Shakeer, L.K.A., Yakasai, M.H., Rahman, M.F., Syed, M.A., Bakar, N.A., Othman, A.R.
    MyJurnal
    Molybdenum is an emerging pollutant. Bioremediation of this heavy metal is possible by the
    mediation of Mo-reducing bacteria. These bacteria contain the Mo-reducing enzymes that can
    conver toxic soluble molybdenum into molybdenum blue; a less soluble and less toxic form of the
    metal. To date only the enzyme has been purified from only one bacterium. The aim of this study is
    to purify the Mo-reducing enzyme from a previously isolated Mo-reducing bacterium Bacillus
    pumilus strain Lbna using ammonium sulphate fractionation followed by ion exchange and then
    gel filtration. Two clear bands were obtained after the gel filtration step with molecular weights
    of 70 and 100 kDa. This indicates that further additional purification methods need to be used
    to get a purified fraction. Hence, additional steps of chromatography such as hydroxyapatite or
    chromatofocusing techniques can be applied in the future.
  4. Veeraswamy Kesavan, Abdulrasheed Mansur, Mohd Syahmi Ramzi Salihan, Rahman, M.F., Suhaili, Zarizal, Shukor, M.Y.
    MyJurnal
    The indiscriminate released of heavy metals and xenobiotics into soils and aquatic bodies
    severely alter soil organisms and the ecosystem. The isolation of xenobiotics degrading
    microorganisms is cost-effective and naturally pleasant approach. Lately, the toxicological effect
    of molybdenum to the spermatogenesis of several organisms has been record. This present study
    is aimed at the isolation and characterization of a bacterium capable of converting molybdenum
    to the colloidal molybdenum blue. Bacteria characterization was performed in a microplate
    format using resting cells. Thus, the reduction process can be employed as a device for
    molybdenum bioremediation. The results of the study revealed an optimum reduction at pH
    between 6.0 and 6.3 and temperatures of between 25 and 40 oC. Similarly, it was also observed
    that a phosphate concentration not greater than 5.0 mM and a sodium molybdate concentration
    at 20 mM was required for reduction. Glucose was observed as the best carbon source to support
    reduction. Following the scanning of molybdenum blue, it revealed an absorption spectrum
    indicating the characteristics of molybdenum blue as a reduced phosphomolybdate. Molybdenum
    reduction is inhibited by heavy metals like silver, lead, arsenic and mercury. Furthermore, the
    ability of the bacterium (Pseudomonas sp. strain Dr.Y Kertih) to utilize several organic
    xenobiotics such as phenol, acrylamide, nicotinamide, acetamide, iodoacetamide, propionamide,
    acetamide, sodium dodecyl sulfate (SDS) and diesel as electron donor sources for aiding
    reduction or as carbon sources for growth was also examined. Finding showed that none was
    capable of aiding molybdenum reduction, however the bacterium was capable of growing on both
    diesel and phenol as carbon sources. GC analysis was used to confirmed diesel degradation.
  5. Yakasai, M.H., Rahman, M.F., Khayat, M.E., Shukor, M.Y., Shamaan, N.A., Rahim, M.B.H.A.
    MyJurnal
    The presence of both heavy metals and organic xenobiotic pollutants in a contaminated site
    justifies the application of either a multitude of microbial degraders or microorganisms having
    the capacity to detoxify a number of pollutants at the same time. Molybdenum is an essential
    heavy metal that is toxic to ruminants at a high level. Ruminants such as cow and goats
    experience severe hypocuprosis leading to scouring and death at a concentration as low as
    several parts per million. In this study, a molybdenum-reducing bacterium with amide-degrading
    capacity has been isolated from contaminated soils. The bacterium, using glucose as the best
    electron donor reduces molybdenum in the form of sodium molybdate to molybdenum blue. The
    maximal pH reduction occurs between 6.0 and 6.3, and the bacterium showed an excellent
    reduction in temperatures between 25 and 40 oC. The reduction was maximal at molybdate
    concentrations of between 15 and 25 mM. Molybdenum reduction incidentally was inhibited by
    several toxic heavy metals. Other carbon sources including toxic xenobiotics such as amides
    were screened for their ability to support molybdate reduction. Of all the amides, only
    acrylamide can support molybdenum reduction. The other amides; such as acetamide and
    propionamide can support growth. Analysis using phylogenetic analysis resulted in a tentative
    identification of the bacterium as Pseudomonas sp. strain 135. This bacterium is essential in
    remediating sites contaminated with molybdenum, especially in agricultural soil co-contaminated
    with acrylamide, a known soil stabilizer.
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