Exercise 9: Culturing the Unculturable

Question 1

What is the purpose of a Winogradsky column?

Answer 1

It is used to study soil and sediment microorganisms that cannot be grown on ordinary laboratory medium

Question 2

What does a Winogradsky column represent?

Answer 2

The Winogradsky column represents a model ecosystem. A series of reactions occur and microbial communities develop in specific microenvironments within the column.

Question 3

What types of environments is it used to study?

Answer 3

aerobic environment at the surface and anaerobic environments below.

Question 4

What types of microbes are present?

Answer 4

• Clostridium=Cellulose-degrading bacteria
• Desulfovibrio=Uses fermentation products as energy and Sulfate as final electron acceptor
• Beggiotoa and Thiobacillus= chemolithotrophs that use H2S as energy source.
• Green algae and Cyanobacteria= Undergo oxygenic photosynthesis producing oxygen for aerobic organisms
• Purple and Green photosynthetic bacteria= undergo anoxygenic photosynthesis

Question 5

Where would they naturally be found? (i.e. in the environment)

Answer 5

Soil and the bottom of any source of water.