Investigation and Partial Purification of Tellurite Reducing Enzyme from a Moderately Halophilic Bacterium Salinicoccus iranensis
Introduction: Excessive use of tellurite nowadays, has suffered the environment from the toxic effects of the oxyanion. Hence, biological treatment of polluted areas is considered as an environmentally friendly and inexpensive method. Although the toxic effects of tellurite for most microorganisms h...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
University of Isfahan
2014-11-01
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| Series: | Biological Journal of Microorganism |
| Subjects: | |
| Online Access: | http://uijs.ui.ac.ir/bjm//browse.php?a_code=A-10-309-1&slc_lang=en&sid=1 |
| Summary: | Introduction: Excessive use of tellurite nowadays,
has suffered the environment from the toxic effects of the oxyanion. Hence,
biological treatment of polluted areas is considered as an environmentally
friendly and inexpensive method. Although the toxic effects of tellurite for
most microorganisms have been reported, but several species of the bacteria
including the halophilic bacteria used in this project can overcome the
toxicity of the oxyanion by its reduction to the elemental form. The aim of
this study was to identify the mechanism (s) involved in tellurite
detoxification.
Materials and
methods: In order to
enhance and maintain enzymatic activity during purification, the test
conditions and enzyme production by the strain were optimized. The optimization
was done by One Factor at A Time (OFAT) method. Several factors, including:
time, various percentages of inoculum, range of pH, concentration of tellurite
and various salts effects were optimized. For assurance tellurite removal was
examined during the experiment. The enzyme was purified by various methods,
including ammonium sulphate precipitation and hydrophobic interaction column
chromatography in which the Concentration of 1.4 M saturated ammonium sulphate
was applied. The purity of the enzyme was assessed by SDS-PAGE during each
phase.
Results: The optimum conditions obtained showed that at 30 hours,
3% inoculum, pH 7.5, without tellurite and with 5% NaCl the highest enzyme
activity and tellurite removal are observed. Purification of the enzyme greatly
reduced the concentration of unrelated proteins and caused a concentrated band
which could be one subunit of the enzyme targeted. The partially purified
enzyme’s fraction was shown to have nitrate and selenite reductase activity
other than tellurite reductase activity.
Discussion and conclusion: This study is an approach to the identification of the halophilic
microorganisms Physiology and enzymes involved in restoring tellurite. The
production of the enzyme responsible for this phenomenon has been optimized and
partially purified. |
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| ISSN: | 2322-5173 2322-5181 |