NATURAL DEFENCE: Marine microbes survive in some of the harshest environments on Earth
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White Robin
Antimicrobial resistance (AMR) is a growing global health crisis, killing millions. Disease-causing microbes are fast learning to defy the drugs they once dreaded. To outpace them, the world needs new medicines — and scientists are increasingly turning to the oceans for help. Mining useful genetic material from marine resources — both microbial and non-microbial — is fast emerging as a new scientific and industrial frontier.
Why oceans? Because marine life is battle-hardened. Marine microbes survive in some of the harshest environments on Earth — amid hydrothermal vents, extreme pressure, high salinity and low nutrients. Many non-microbial marine organisms, meanwhile, are soft-bodied and largely sessile or sedentary. Lacking physical defences, they rely on potent chemical weapons to survive predators, infections and competition.
The scientific effort today is to identify these natural defence mechanisms, copy them and mass-produce them as drugs or molecular tools.
The idea itself is not new. Marine bio-resources have been studied for decades, largely for natural products and basic research. What has changed in the past 10–15 years is the feasibility of the idea. Cheap genome sequencing, metagenomics (the study of the genomes of entire microbial communities at once), AI-driven screening and advances in synthetic biology have made it possible to mine marine microbes for the development of new drugs.
Scientists are now diving into oceans — literally and figuratively — in search of solutions for AMR.
A seminal contribution in this field has come from scientists at BGI Research (formerly Beijing Genomics Institute), China, led by Jianwei Chen. The team recovered 43,191 bacterial and archaeal genomes from publicly available marine metagenomes. (Archaea are microbes distinct from bacteria and plants or animals; their genomes represent the genetic blueprints of ancient life forms, often living in extreme environments.)
In a 2024 paper titled ‘Global marine microbial diversity and its potential in bioprospecting’, published in Nature, the researchers report that computer-based bioprospecting of these genomes led to the discovery of a novel CRISPR–Cas9 system (a programmable DNA cutter and potential new molecular tool), 10 antimicrobial peptides and three enzymes capable of degrading PET plastic.
Calling Chen’s work a “breakthrough”, Zhi-Feng Zhang of Shenzhen University notes that the team identified 117 antimicrobial peptide candidates using deep-learning tools and synthesised 63 of them. Ten showed strong antimicrobial activity, working against five bacterial strains, including human pathogens.
“The potential of marine microbes as a reservoir of new enzymology and natural products for bioprospecting remains largely underestimated,” Zhang writes in Engineering Microbiology, pointing to the “unprecedented opportunities” marine genetic resources offer.
Research in India
India, too, appears to be catching up. A key development is the establishment of a deep-sea marine microbial repository by the National Institute of Ocean Technology, near its sea-facing campus in Nellore, Andhra Pradesh. The facility is part of the ₹4,000 crore deep-sea mission of the Ministry of Earth Sciences.
Academic literature, too, reflects these developments. A recently published book, Marine Microbiome and Microbial Bioprospecting, containing 39 chapters by multiple scientists, provides a comprehensive overview of the microbial diversity across marine ecosystems and their bioprospecting potential.
Several chapters focus on drug discovery and AMR. In one on anti-tuberculosis research, scientists from CSIR–Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar, note that marine microbes produce structurally diverse metabolites with potent anti-mycobacterial activity. Compounds such as ilamycin, atratumycin, cyclomarin A and diazaquinomycin, they say, show strong promise and are backed by genomic and biosynthetic studies that enable scalable production.
Collectively, marine microorganisms represent a powerful but under-explored arsenal against drug resistance. As microbes on land continue to outsmart existing medicines, the next generation of life-saving drugs may well come from the depths of the sea.
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Published on December 29, 2025
