Guwahati: Picture this: tiny, invisible helpers working tirelessly underground to clean up pollution, boost plant growth, and fight crop diseases—all without leaving behind harmful side effects. Researchers from the Indian Institute of Technology Bombay (IIT Bombay) are turning this vision into reality, using bacteria to tackle some of the toughest challenges facing agriculture today.
Large-scale manufacturing and excessive use of synthetic organic chemicals in agriculture have resulted in the release of genotoxic aromatic pollutants into multiple biosphere compartments. Various aromatic compounds like naphthalene, benzoate, phthalates and their derivatives are extensively used in different industries like cosmetics, textiles, food and feed preservatives, dyes, single-use manufacturing, petroleum as well as in large quantities to agricultural fields as pesticides. Excessive usage of these compounds has led to contamination of ecosystems like soil, water and bioaccumulation in the food chain.
The majority are mutagenic, endocrine disrupting, carcinogenic and are known to cause environmental hazards, compromise soil health and negatively affect biota, including humans. Moreover, the entry of aromatic compounds into agricultural fields from irrigation, application of pesticides, leaching from mulching films, etc. lead to the accumulation of these pollutants in soil and subsequently cause toxicity to crop plants. Aromatics like Carbaryl, naphthalene, phthalates, etc. have been reported to cause seed mortality and phytotoxicity (suppressed growth of shoot and roots, wilting, chlorosis, reduced biomass, transpiration rates and crop yield) to various crop plants.
In a groundbreaking study published in Environmental Technology & Innovation, scientists at IIT Bombay have demonstrated how certain bacteria not only remove toxic pollutants from the soil but also enhance its fertility, help plants thrive, and ward off harmful fungi. These findings could reduce our dependence on chemical fertilizers, pesticides, and fungicides, offering an eco-friendly alternative for sustainable farming.
Cleaning Polluted Soil with Bacteria
Soil contamination from aromatic compounds (organic compounds with a benzene-like ringed structure) in the form of pesticides (insecticide and herbicide) is one of the major issues the agriculture industry faces today. These compounds are toxic, can inhibit seed germination, reduce plant growth and yield, and also accumulate in seeds and plant biomass. Many aromatic pollutants such as carbaryl, naphthalene, benzoate, 2,4-dichlorophenoxyacetic acid and phthalates are extensively used in pesticide formulation and also released as by-products from various other industries, like cosmetics, textile, construction, food and feed preservatives, dyes, petroleum, and plastics. Traditional approaches to remove these pollutants, like chemical treatments or soil removal, often turn out to be band-aid solutions – expensive and unable to tackle the problem completely.
The IIT Bombay team identified bacteria from toxic environments. While doing so, they noticed that certain bacterial species, specifically from the genera Pseudomonas and Acinetobacter, were especially good at breaking down aromatic compounds. “These bacteria were isolated from contaminated soil and agricultural fields. They feed on pollutants, breaking them into simpler, harmless, non-toxic compounds. In this way, they act as natural cleaners of polluted environments,” explains Prof. Prashant Phale, from the Department of Biosciences and Bioengineering at IIT Bombay, under whose guidance Sandesh Papade carried out the research for his PhD work.
A Two-in-One Solution for Farmers
These tiny organisms aren’t just cleaning up soil—they’re making it more fertile too.
While breaking down aromatic pollutants, these bacteria were also found to convert insoluble forms of essential nutrients, such as phosphorus and potassium, into soluble forms and make them readily available to the plants. They also produce siderophores, which help plants absorb iron in nutrient-limited environments. Moreover, these bacteria also contribute to plant growth and health by creating a high amount of growth hormone called indoleacetic acid (IAA). “So, while these bacteria are cleaning the soil, they are also helping plants grow healthier and more robust by fertilising the soil and improving soil health,” Prof. Phale added.
Interestingly, when a mixture of bacteria from the Pseudomonas and Acinetobacter genera is used, they significantly boost the growth and yield of crops (wheat, mung bean, spinach, fenugreek, etc.) up to 45-50%. “As they say, ‘unity is the best policy.’ Some strains might be good at breaking down pollutants, while others might be better at promoting plant growth or defending against diseases. By combining them, we assembled a team of bacteria that can work together cooperatively, doing jobs simultaneously and more efficiently,” remarks Prof. Phale.
Natural Defenders Against Fungi
Fungal diseases are another problem affecting several crops worldwide. According to the Food and Agricultural Organisation of the United Nations, hundreds of fungal diseases impact 168 crops essential to human nutrition. Despite the use of fungicides and disease-resistant cultivars, fungal infections still cause global crop losses of 10–23% annually, with key calorie crops consumed in India, like rice and wheat, particularly affected.
The bacteria studied by IIT Bombay offer a gentler alternative. They produce natural antifungal substances like lytic enzymes and hydrogen cyanide, which target harmful fungi without collateral damage. “These bacteria act like a natural defence system for plants,” says Prof. Phale.
Toward Sustainable Farming Solutions
While these findings hold immense promise, there’s still work to be done before farmers can widely adopt this technology. Prof. Phale believes that “it will take some time for widespread adoption, as the technology will need to be scaled up, tested in different environments, and made available as commercial products.”
In the future, researchers also want to test how these helpful bacteria benefit plants during droughts and other environmental stress conditions.
They also intend to create easy-to-use products, called “bio-formulations,” that combine the bacteria with natural materials, making them long-lasting and simple for farmers to apply in agriculture fields.
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