VIT Researchers Discover Antibiotic-Producing Thermophilic Actinobacteria in Rajgir Hot Spring

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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