Helicobacteria · Heliobacteria are Gram-positive, endospore-forming, anoxygenic phototrophic bacteria found in anaerobic soils and paddy fields. · Example – Heliobacterium chlorum , Heliobacillus mobilis , Heliospirillum photoanaerobium and Heliomicrobium modesticaldum . · Number of Species – There are over 40 validated species within the Helicobacter genus, with new species occasionally being discovered in different animal hosts. · Habitat – Soil, paddy fields, hot springs, alkaline soils, anaerobic mud, soda lakes; commonly found in waterlogged agricultural fields (especially rice field). · Mode of Nutrition – Photoheterotrophic, require organic carbon sources and use light as an energy source. · Mode of Reproduction – Reproduce asexually via Binary fis...
Green Non-Sulfur Bacteria · Example – Chloroflexus aurantiacus , Chloronema giganteum , Oscillochloris trichoides and Herpetosiphon aurantiacus. · Number of Species – Around 30 – 35 species. · Habitat – Hot springs, alkaline springs, marine sediments, microbial mats, geothermal areas; thrive in hot, low-oxygen, illuminated environments. · Mode of Nutrition ü Photoheterotrophy (Primary Mode): They preferentially use light for energy but require organic compounds (e.g., sugars, amino acids, organic acids) as carbon sources. ü Photoautotrophy (Alternative Mode): Some, like Chloroflexus, can fix CO ₂ , but they use a unique pathway called the 3-Hydroxypropionate pathway, which is different from the Calvin cycle (used by plants and purple bacteria) and the rTCA cycle (used by green sulfur bacteria). ü Chemoheterotrophy:...