Plastic Predators: The Microbes Devouring Our Waste - Part 1

- Khushi Dubey, Rushi Joshi*

Fig: A cartoon schematic

The Plastic Crisis: A Problem That’s Now Inside Us

Discussions about plastic pollution in oceans are everywhere. Images of turtles with straws in their noses have circulated widely. But plastic pollution is no longer just an external issue—it has entered human bodies. Scientists just found microplastics in human blood, organs, and breast milk. These particles—smaller than a human hair—carry toxins that disrupt hormones, damage cells, and linger in your body for decades. This isn’t a problem ‘out there.’ India generates 3.5 million tonnes of plastic yearly. Delhi’s landfills are mountains of trash. The Ganga carries 1.15 lakh tonnes of plastic to the sea. But this waste doesn’t stay put. It breaks down, invades our food, water, and air—and becomes part of us.

Let us follow a single plastic bottle. When discarded, it fractures in sunlight and becomes microplastic. Rain washes them into the ground, where crops absorb them. Fish devour them in the waterways. You sip them with tap water. Breathe in Delhi's pollution. They gradually accumulate. According to studies, they are associated with infertility, cancer, and immunological diseases. By 2040, plastic in our bodies might have altered human DNA. An average Indian ingests 5 grams of plastic weekly—a credit card’s weight. This is biological warfare, and we’re losing it!

Physical methods such as photodegradation harness sunlight to weaken plastic polymers, although this process tends to be slow and incomplete [Andrady, 2011]. In contrast, thermal degradation takes a more dramatic approach by heating plastics to high temperatures, transforming them into fuels or simpler compounds. Yet, this method demands vast amounts of energy and can release harmful emissions into the atmosphere [Hopewell et al., 2009].

Another avenue is chemical recycling, which uses solvents or catalysts to deconstruct plastics back into their original building blocks. Despite its potential, this technique remains complex and expensive, limiting its practical application [Geyer et al., 2017]. Mechanical recycling, where waste plastics are repurposed into new products, also faces significant hurdles. The challenges of contamination and the gradual loss of quality over repeated cycles prevent it from being a perfect solution [Geyer et al., 2017].

Amid these challenges, microbial degradation offers a naturally efficient and eco-friendly alternative. Microorganisms work under normal environmental conditions, breaking down plastics completely into non-toxic substances. Their enzymes perform this task with far less energy and without producing harmful by-products. This natural process not only minimizes environmental impact but also adapts more readily to different types of plastics, often outperforming conventional methods in both efficiency and sustainability [Smith et al., 2020] [Carbios, 2022]. 

How do Microbes Turn Plastic into Life? 

Meet Ideonella sakaiensis - a bacterium discovered in a Japanese recycling plant. Its secret weapon is the PETase, an enzyme that slices through PET plastic like molecular scissors. Here’s how it works-

1. PETase latches onto the plastic and cuts its ester bonds, breaking them into terephthalic acid and ethylene glycol.

2. Another enzyme, MHETase, chops these fragments into bite-sized pieces. 

3. 3. The bacteria eat these molecules, turning plastic into energy, water, and more microbes. It’s nature’s ultimate recycling program.

   
   

Fig: Ideonella Recycling Process (In labs, this Ideonella can devour 90% of a plastic bottle in 6 weeks! )

Meet Pseudomonas bharatica - a soil bacterium discovered right here in India. Its mission? Destroy plastic bags. How? It secretes lipases and oxidases, enzymes that corrode LDPE plastic’s carbon backbone. Over 60 days, it eats through 40% of a bag, turning it into harmless fatty acids. 

Fig: A Lab research visualisation

However, nature's instruments move slowly. So, scientists are hijacking evolution. At the University of Portsmouth, researchers utilized CRISPR to modify PETase's structure, resulting in PETase FAST, a mutant enzyme that digests plastic 20% as quickly. How? By solidifying its hold on the plastic!

To create cracks in stubborn plastics such as polyethylene, scientists use UV light. Others apply solvents to soften the surface. In Bengaluru, the company TerraNano uses algal biofilms to capture microplastics in lakes. What's the goal? Make germs work everywhere and not just in labs. 

THE GLOBAL REVOLUTION and INDIA’s ROLE 

In 2016 at Kyoto University, Japanese scientists stumbled upon Ideonella sakaiensis in a recycling plant. This bacterium could eat PET plastic—the kind in your soda bottles. How? It produced PETase, an enzyme that snipped plastic into edible bits. The world took notice. Suddenly, plastic wasn’t waste—it was food.

France’s Carbios took it further. They built bioreactors where enzymes recycle PET into virgin-quality plastic in 10 hours. Famous and established brands like L’Oreal and Pepsi now use it. 

India wasn’t just watching—it was innovating! 

Fig: Indian demographic

While the Ganga carries 1.15 lakh tonnes of plastic yearly, Indian scientists are fighting back. At IIT Delhi, Dr. R.K. Jain’s team engineered Bacillus subtilis biofilms to trap microplastics in the river’s sediment. ‘It’s a living filter,’ he says. ‘Nature does the heavy lifting’

In Kanpur, Ankit Agarwal’s startup (Phool.co) rescues 8.4 tonnes of temple flowers daily. Using fungi, they turn this sacred waste into ‘Fleather’—a biodegradable alternative to plastic packaging. ‘We’re merging faith with science,’ Ankit says. ‘The Ganga deserves better.’

Hyderabad’s Banyan Nation uses AI to optimize microbial mixes, recycling FMCG waste into food-grade plastic. Partnering with Unilever, they’ve diverted 1,000+ tonnes from landfills.

‘It’s not charity,’ says co-founder Mani Vajipey. ‘It’s smart business.

Pune’s CSIR labs brew microbial cocktails. Hyderabad’s startups blend AI and biology. Kanpur’s tem has become a recycling hub. This is a distributed revolution—no single hero, but countless unsung warriors.

With 3.5 million tonnes of annual plastic waste and a biotech sector growing at 15% yearly, we’re in the battleground now.

Government initiatives:

Every innovation needs muscle. In 2022, India’s Extended Producer Responsibility (EPR) law mandated brands to recycle 30% of their plastic by 2025. Fines loom for non-compliance. Meanwhile, the Swachh Bharat Mission funds bioremediation of 100+ landfills with ₹1,400 crore. At Delhi’s Ghazipur landfill, CSIR’s microbial cocktails are breaking down mountains of LDPE.

‘We’re not just cleaning trash,’ says Dr. Swapnil Sharma. ‘We’re healing ecosystems.’ 

We will continue in the next part with :

• The challenges of this new promising way to get our earth back and have a better fighting chance.

• The Market and career opportunities it generates for students to look forward.