The Effect of Environmental Factors Such as Temperature, Osmotic Pressure, Oxygen Concentration and Ph on Microbial Growth and Survival

2288 words 10 pages
The effect of environmental factors such as temperature, osmotic pressure, oxygen concentration and pH on microbial growth and survival

Microbial growth can be affected by different environmental factors such as temperature, osmotic pressure, oxygen concentration and pH. Six experiments were carried out in this report testing for microbial growth against different environmental factors. Good aseptic techniques were used to prevent contamination, resulting in a uniform set of results that are in line with the literature.

Bacteria vary greatly in terms of their characteristics and morphology. Colonies can be classified according to their colour, form, elevation, margin and size. Pure cultures of microorganisms
…show more content…
The colonies of M. Luteus were yellow in colour, circular colonies which are convex with entire margins.

Experiment 2: Selective and differential plating
Table 1: The size, sheen and colour of the colonies of the organisms on the EMB plate E. coli E. aerogenes B. subtilis
Size Small Small No growth
Sheen Green sheen No green sheen -
Colour Black Purple/pink -

Experiment 3: Effect of temperature on bacterial growth
Table 2: Microbial growth of the cultures incubated at varying temperatures (+ growth, - no growth) Growth of cultures
Slant Temperature (oC) E.coli P.fluorescens B.stearothermophilus
1 -4 - + -
2 25 + + +
3 37 + - +
4 65 - - +
5 85 - - -

Experiment 4: Effect of environmental factors on microbial growth – osmotic pressure
Table 3: Microbial growth of cultures on nutrient agar plate with varying salt concentration (+ growth, - no growth)

% Salt E. coli M. luteus V. natriegens
0.5 + + +
5 - - +
6.5 - - +
10 - - +

Experiment 5: Effect of oxygen concentration on bacterial growth
Table 4: Amount of microbial growth present in the molten agar previously boiled to drive off oxygen when 0.5ml of each bacterium was inoculated.

Inoculated bacterium Growth
E. coli Scattered growth at the top and throughout
C. sporogenes Scattered growth at the bottom
B. subtilis Growth at the top

Experiment 6: Effect of environmental factors on microbial growth – pH

Table 5: Microbial growth of salin cultures at


  • Causes and Effects of Economic Growth
    1720 words | 7 pages
  • The Effect of Temperature on the Solubility of Carbon Dioxide in Water Under Constant Pressure
    2244 words | 9 pages
  • Bacterial Growth Rates
    879 words | 4 pages
  • Solubility Equilibrium and the Effect of Temperature
    1210 words | 5 pages
  • The Effect of Substrate Concentration, Enzyme Concentration, Ph and Temperature on Enzyme Activity”
    1390 words | 6 pages
  • Effect of Varying Temperatures on Enzymatic Activity of Bacterial and Fungal Amylase and Hydrolysis of Starch
    2755 words | 12 pages
  • The Effect of Enzyme Concentration on Rate of Reaction
    2616 words | 11 pages
  • Positive Effect of Peer Pressure
    939 words | 4 pages
  • Coca Cola External Environmental Factors
    1009 words | 5 pages
  • Effects of Temperature on Catalase Activity
    995 words | 4 pages