Winogradsky Column

Bacteria that fix carbon dioxide and derive their energy from the oxidation of inorganic ions are defined as what?
Chlorobium is a member of which group of which group of bacteria?
phototrophic green sulfur bacteria
Name two genera of bacteria that are photoheterotrophs.



What very strong acid is produced by Thiobacillus when it oxidizes reduced forms of sulfur?
sulfuric acid
What organism carries out sulfate respiration producing sulfides that cause the bottom of a Winogradsky column to turn black?
Desulfovibrio deslfuricans
The anoxygenic photosynthetic bacteria differ from plants in that the bacteria do not split water to produce what compound?
Anoxygenic photosynthetic bacteria do not split water to produce O2, instead they split H2S to form organis sulfur.
What two photosynthetic pigments are synthesized by the purple nonsulfur bacteria?

  • bacteriochlorophyll
  • carotenoids

What wavelengths of light are absorbed by bacteriochlorophyll and carotenoids?

  • bacteriachlorophyll: 800-1000 nm
  • carotenoids: 600-700 nm

What type of growth conditions are necessary for the culture of the green and purple sulfur bacteria?
They grow only under strict anaerobic conditions.
The red to brown coloration of cultures of the purple nonsulfur bacteria is due to what pigments?
Both bacterichlorophyll and carotenoids combine to produce colors of broun, purple-reds, red, and green; however the carotenoids are the red-orange pigment and combined with the green of bacteriachlorophyll will produce brown
What substances are used by sulfate-reducing bacteria for their carbon requirements?

  • lactate
  • pyruvate

Give examples of habitats where sulfate reducing bacteria are found.

  • anaerobic sewage digesters
  • water-logged soil
  • paper mill waste ponds

Which organisms can be found in the anaerobic zone.

  • Cellulomonas
  • Desulfovibrio desulfuricans
  • Clostridium
  • Chlorobium
  • Chromatium

Which organisms grow in the black zone?

  • Clostridium
  • Desulfovibrio desulfuricans

For what is Cellulomonas responsible?
Celluomonas reduces the cellulose to monosaccharides to be femented by organisms like Clostridium.
What role do organisms like Clostridium have?
Clostridium and other fermenters, ferment the monosaccharides broken down by the Cellulomonas into organic acids like lactate and pyruvate.
What do sulfate reducing bacteria do?
Anaerobic sulfate reducing bacteria such as, Desulfovibrio desulfuricans, utilize the lactate, produced by fermentation, and the sulfate in the column to carry out sulfate respiration.
What is sulfate respiration?

In this process, sulfate serves as a terminal electron acceptor, and its reduction(and ETC) produces ATP. The process reduces sulfate to H2S which forms a black precipitate.

The sulfide diffuses upward and is made available to organisms which are sulfide oxidizers (Beggiatoa, Thiothrix, Thiobacillus) which produce sulfate which can be used by the sulfate reducers again.

Which organisms live in the black zone?

  • Clostridium
  • Desulfovibrio desulfuricans

Which organisms live in the Green zone?
What type of organism is Chlorobium?

  • Phototrophic green sulfur bacteria
  • anoxygenic photosynthesis
  • reduces H2S to elemental sulfur but stores it outside of the cell
  • fixes CO2 in the Krebs cycle (not Calvin)
  • greenish zones in mud due to presence of bacteriochlorophyll

What are phototrophic purple sulfur bacteria?

  • anoxygenic photosynthetic bacteria
  • H2S is source of reducing power and is reduced to elemental sulfur which is stored inside of the cells as sulfur granules
  • have photosynthetic pigments bacteriochlorophyll and carotenoids
  • Chromatium

What is Chromatium?
phototrophic purple sulfur bacteria
What are examples of purple nonsulfur bacteria?

  • Rhodobacter
  • Rhodospirillum

What are the characteristics of purple nonsulfur bacteria?

  • photoheterotrophic using organic compounds as a carbon source, and obtaining their energy from anoxygenic photosynthesis (normal)
  • can be photoautotrophic using CO2 as a carbon source and hydrogen gas or low concentrationof sulfide as reducing power
  • can grow heterotrophic on organic acids using respiration should light become very limited
  • are found in microaerophilic regions as brownish reddish cultures where the mud interfaces with the water

What are some examples of chemolithotrophic bacteria?

  • Thiobacillus
  • Beggiatoa

What are the characteristics of chemolithotropic bacteria?

  • grow in the aerobic zone of the column
  • obtain energy by oxidizing reduced forms of sulfur (H2S) to sulfate or sufuric acid.
  • use carbon dioxide for carbon requirements
  • Beggiatoa, Thiothrix, Thiobacillus

what are sheathed bacteria?

  • filamentous bacteria with a fungal like growth cycle.
  • they eat a variety of organic compounds
  • they like nutrient rich environments (hay infusions)
  • form masses of fine filaments often encrusted with iron
  • sheathed bacteria take in chelates, oxidize the carbon compound, and release ferrous iron – which oxidizes on their surface (iron rich water)
  • Leptothrix Sphaerotilus

also called a producer, is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) from simple inorganic molecules using energy from light (by photosynthesis) or inorganic chemical reactions (chemosynthesis). They are the producers in a food chain, such as plants on land or algae in water. They are able to make their own food and can fix carbon.
What do algae and cyanobacteria do?
they grow in the water and on the surface of teh column producing oxygen which keeps hte upper portion of the column aerobic.
Categories: Microbiology