I will do three different practical experiments to investigate the growth and isolation of bacteria and the characteristics of different microbes. They are:Pouring Streaking Environment

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Hani Ali          BTEC National diploma in science

Practical report

Microbial techniques

Introduction

I will do three different practical experiments to investigate the growth and isolation of bacteria and the characteristics of different microbes.

 They are:

  • Pouring
  • Streaking
  • Environment

Pouring plates

Pouring plates can be used to investigate if bacteria can grow on a solidified nutrient agar by following the aseptic techniques carefully.

The aseptic techniques used were:

  • Flaming the neck of the bottle by passing the opening through a Bunsen burner
  • The lid of the bottle is opened using the small finger of the other hand during procedure to avoid placing the lid on the bench, where it can be contaminated

Apparatus

Bunsen burner

Bottle containing a nutrient agar

Petridish

Matches

Method

  1. Remove the bottle containing molten nutrient agar from the hot water. Allow the liquid agar to cool down.
  2. light the Bunsen burner and adjust it to blue flame
  3. Open the bottle with little finger on the other hand to avoid placing the lid on the bench.
  4. Flame the neck of the bottle for a few seconds. This is done to produce an upward flow of air from the bottle so that any organism in the area will not fall into the bottle.
  5. Pour the molten agar slowly into the base of sterile petridish, lifting the lid only as much as necessary. Do no not spill agar on the edges of dish.
  6. Replace the lid and allow the agar to set, by gently rotating to get even layer of agar.
  7. Secure the dish with adhesive, by using two pieces of tape to fasten the lid, but do not seal all the way round as this cold create anaerobic condition and encourage the growth of possible pathogenic microorganisms.
  8. The plate can be used for streaking or spreading, when the agar solidifies.
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Results

There was no contamination of any kind of bacteria

Discussions and conclusion

One disadvantage is that some of the solution will be left behind in the bottle. This can be avoided by transferring the suspension to the petredish, adding molten agar, then swirling the plate to mix the two liquids. However, even when plate is swirled repeatedly and in directions, the liquids are not mixed as evenly as in the former procedure.  

Streak plate

Streaking plate for single colonies is one of the most important techniques used by microbiologists, since it ...

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