Chennai | May 2026
In a significant breakthrough for tackling plastic pollution, researchers in Chennai have identified a naturally occurring freshwater microalgae capable of breaking down plastic waste in polluted water bodies within just three months.
A study conducted by the Centre for Advanced Studies in Botany at the University of Madras found that a species called Uronema trentonense isolated from plastic waste in Rajakilpakkam Lake, can degrade up to 27 percent of high-density polyethylene (HDPE) and 21 percent of low density polyethylene (LDPE) over a 12 week period under controlled laboratory conditions.
HDPE and LDPE are among the most widely used plastics in everyday life, commonly found in bottles packaging materials and household items, making the discovery particularly relevant in the fight against urban plastic pollution.
According to the researchers algae works through a combination of biological, chemical, and physical processes. It attaches itself to plastic surfaces and forms a biofilm, which gradually alters the structure of the plastic. This leads to the weakening of polymer chains, allowing enzymes produced by the algae to break the material down into smaller fragments.
Over time, the plastic begins to show visible signs of degradation, including cracks, pits, and increased surface roughness. These fragments are further converted into simpler compounds such as fatty acid derivatives, some of which the algae uses as a carbon source for growth effectively enabling it to “consume” parts of the plastic.
Lead researcher Nagaraj Subramani noted that the findings could contribute to achieving global sustainability targets, particularly those focused on responsible consumption and production. The study highlights how naturally occurring organisms can be harnessed to address one of the most pressing environmental challenges.
The research team initially identified around 50 species of microalgae from plastic waste collected in the lake. From these, 10 species were shortlisted for detailed analysis based on their ability to colonise plastic surfaces. While several species showed varying levels of degradation, Uronema trentonense emerged as the most effective, followed by species like Nostoc and Stigeoclonium.
Earlier work by the same team had also identified other algae, including Coccomyxa species, capable of degrading plastics by up to 24 percent. That research examined over 200 algae species across multiple water bodies in and around Chennai, pointing to the potential of native algae in managing freshwater pollution.
However, the scientists cautioned that not all plastics are equally vulnerable. Materials such as PET, polypropylene (PP), and PVC showed much lower degradation rates, indicating that further research is needed to tackle a broader range of plastic types.
The discovery opens new possibilities for eco-friendly waste management strategies, especially in urban lakes and water systems struggling with plastic accumulation. Researchers believe that with further development, such algae-based solutions could be integrated into large-scale environmental cleanup efforts, offering a sustainable and cost-effective alternative to traditional methods.