Effect of Varying NaCl Concentrations on the Growth Curve of Escherichia coli and Staphylococcus aureus
Omotoyinbo O. V.,
Omotoyinbo B. I.
Issue:
Volume 4, Issue 5, September 2016
Pages:
31-34
Received:
18 January 2017
Accepted:
3 March 2017
Published:
18 March 2017
DOI:
10.11648/j.cb.20160405.11
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Abstract: The effect of NaCl concentration on the growth of gram negative Escherichia coli and gram positive Staphylococcus aureus cells cultivated at 37°C was studied in an effort to understand the importance of NaCl to the growth of these bacteria. The bacteria were grown on standard nutrient agar in three groups containing NaCl concentrations; 0, 1.0 and 3.0% (w/v) with tubidimetric readings of absorbance taken at hourly intervals to obtain their growth curve. NaCl had an effect of shortening the latent period of growth in S. aureus previous to rapid growth, producing a characteristic lag phase which appears to have a somewhat greater accelerating effect than that obtainable in E. coli which is characteristic of most standard growth curves. At 0% (w/v) NaCl concentration, optimal growth of both E. coli and S. aureus was observed (0.557 and 0.583 respectively). However, an increase in the concentrations of NaCl above 0% to 1.0 and 3.0% decreased growth at 37°C. Hence, it was observed that the extent to which growth was suppressed was directly proportional to the increasing concentration of NaCl. Therefore NaCl was observed to inhibit growth of both bacteria at 37°C
Abstract: The effect of NaCl concentration on the growth of gram negative Escherichia coli and gram positive Staphylococcus aureus cells cultivated at 37°C was studied in an effort to understand the importance of NaCl to the growth of these bacteria. The bacteria were grown on standard nutrient agar in three groups containing NaCl concentrations; 0, 1.0 and ...
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