Researchers from the Vellore Institute of Technology (VIT) in Tamil Nadu have recently discovered thermophilic Actinobacteria in the Rajgir hot spring lake in Nalanda, Bihar.

• They used 16S rRNA metagenomics to study microbial diversity.

About Thermophilic Actinobacteria

• They are a group of heat-loving bacteria within the phylum Actinobacteria that thrive at elevated temperatures (typically 45–70°C).
• Competitive Advantage: Thermophilic bacteria produce antibiotics to outcompete other microbes in these hostile yet mineral-rich habitats.
• Natural Habitat: Hot springs, Deep-sea hydrothermal vents, Geothermal areas (e.g., volcanic sites, tectonic zones), Peat bogs, compost piles, and decaying organic materials.
• Survival Mechanisms: Some thermophilic bacteria produce antimicrobial compounds to eliminate microbial competitors in these high-temperature, low-competition environments. Examples include: Bacillus strains, Streptomyces strains.
  • Some survive by other physiological adaptations such as heat-stable enzymes or thickened cell walls.
• Significance: 
  • Thermophilic enzymes are used in industrial applications: Example: Thermus aquaticus enzyme used in PCR tests.
  • Agricultural Utility: Thermophilic bacterial consortia from Indian hot springs (e.g., Chumathang, Leh) have shown plant growth promoting traits.

Key Findings Of the Researchers

• Abundance of Actinobacteria: Researchers found that Actinobacteria made up 40–43% of the microbial diversity at Rajgir unusually high compared to other hot springs where it’s typically around 20%.
• Actinobacteria as Antibiotic Producers: This group of bacteria is known to produce antibiotics like streptomycin and tetracycline, making their abundance at Rajgir significant in the fight against antimicrobial resistance.
  • The antibiotic resistance is rising globally, with WHO warning of $1 trillion in healthcare costs by 2050 due to resistant infections.
• Identification of Bacterial Strains: Researchers cultured isolates against pathogens such as  E. coli, Salmonella, Klebsiella, Pseudomonas, Staphylococcus and identified 7 Actinobacteria strains with potent antimicrobial activity.
• Diethyl Phthalate: Diethyl phthalate, extracted from Actinomycetales bacterium spp. found in Rajgir hot spring, was found to inhibit Listeria monocytogenes, a deadly foodborne pathogen, indicating potential for new antibiotic development.

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