Saran's Learn Microbiology

Purple Sulfur Bacteria ·        Example – Chromatium , Allochromatium, Thiocapsa , Thiocystis, Thiospirillum , Ectothiorhodospira and Lamprocystis. ·        Number of Species – Over 100 described species were identified within the group belonging mainly to the family Chromatiaceae (Class: Gammaproteobacteria) and Ectothiorhodospiraceae. ·        Habitat – Anaerobic aquatic environments, especially: ü   Stagnant Water Bodies: Lakes, ponds, and lagoons, especially those with decaying organic matter. ü   Sulfur Springs: Environments where Hydrogen sulfide is geothermally produced which includes Sulfide-rich stagnant waters, lagoons, lakes, and hot springs. ü   Salt Marshes and Microbial Mats: In the deeper, anoxic layers where sulfide is present. ü   Meromictic Lakes: Permanently stratified lakes where the deeper layer (hypolimnion) is anoxic and may contain...

Cyanobacteria (Blue – Green Algae) ·        Cyanobacteria, commonly known as Blue Green Algae, are ancient Photosynthetic Prokaryotes with significant Ecological and Evolutionary roles. ·        Example - Anabaena , Nostoc , Oscillatoria , Spirulina , Gloeocapsa , Microcystis, Synechococcus and Prochlorococcus. ·        Number of Species – Approximately 8,000 species are estimated, though taxonomic debates persist. Around 5,185 species have been formally categorized into seven orders, including Chroococcales and Synechococcales. ·        Habitat ü   Freshwater: Lakes, ponds, rivers. ü   Marine: Oceans, seas, intertidal zones. ü   Terrestrial: Moist soils, rocks, tree bark. ü   Extreme Environments: Hot springs, hypersaline environments, deserts, polar regions. ü   Symbiotic Relationships: With Plants (e.g., Azolla ), ...

GENERAL CHARACTERISTICS OF PHOTOSYNTHETIC BACTERIA Photosynthetic Bacteria are Prokaryotic organisms capable of converting Light energy into Chemical energy through Photosynthesis. Unlike plants, many of them do not produce Oxygen (except Cyanobacteria) during this process. Cellular Structures: Photosynthetic Bacteria may be unicellular, filamentous, or colonial. Some can form specialized cells like Heterocysts (for nitrogen fixation in cyanobacteria) or Chlorosomes (light-harvesting structures in green bacteria). Habitat - Photosynthetic bacteria are found in a wide array of habitats, including aquatic (freshwater and marine), terrestrial (soil), and extreme environments (hot springs, salt lakes). Biochemical Composition - Photosynthetic Bacteria contain a high Protein content (40 – 60 %), with pigments and vitamins making up a significant portion of their cellular dry weight. Mode of Nutrition - Many exhibit metabolic flexibility, capable of different modes of nutrition (e.g., Pho...