Green sulfur bacteria and green nonsulfur bacteria are photosynthetic bacteria found in aquatic environments. They are gram-negative, anaerobic bacteria that range in shape from spherical to curved rods. They contain bacteriochlorophylls and carotenoids that allow them to carry out photosynthesis. These bacteria play important roles in the biogeochemical cycles of carbon, nitrogen, and sulfur through their ability to oxidize sulfide or fix molecular nitrogen. They are typically found in sulfur-rich mud and waters.

1. Green sulfur bacteria
and Green nonsulfur
bacteria

2. Green sulfur bacteria and Green nonsulfur
bacteria
TAXONOMY
• Kingdom:Bacteria
• Phylum:Cholorobi
• Class:Chlorobia
• Order:Chlorobiales
• Family:Chorobiaceae
• Genus:Chlorobium
• Representative Species:Chlorobium

3. General Morphology
• Gram-negative
• Spherical,Ovoid,Straight or Curved Rod-Shaped
• 0.3-1.1 um wide &0.4-3 um longor,sometimes,much
longer.
• Streptococci from filamentes;curved rod shaped
strains from long spirals.
• Non-motile
• Color can be either grass-green or chocolate brown.
• Storage materials:polyphosphate and polysaccharides.

4. Photo-synthetic pigments
• cytoplasmic membrane & chlorosomes.

5. Physiology
• Tropismphototrophic & Photolithoautotrophic
growth.
• Obligately anaerobic
• 20-350 C
• Ammonia is used as nitrogen source;molecular
nitrogen is fixed by many strains.
• Major carotenoid:Chlorobactene
• Bacteriochlorophylls c,d or e
• +small amounts of bacteriochloro- phyll a

6. Cont.,
Sulfide Oxidation:
• In sulufied-reduced media,thiosulfate = electron
donor substrate with sulfur = electoen donor.
• In the presence of reduced sulfur compounds and
bicarbonate,simple organic substrates can be
photoassimilated.

7. Habitat/Ecology:
• Hydrogen sulfied-containing mud andwater of
freshwater,brackish water and marine environments.
What is their significance?
• Essential for the natural cycling of sulfur.
• Contribute to the biogeochemical cycling of
carbon,nitrogen and sulfur.

8. Reference
https://prezi.com/vac6uyw9vwic/green-sulfur-and-
nonsulfur-bacteria/