Breakthrough in Plasticiser Degradation Technology

The alarming rise of carcinogenic plasticisers in the environment has become a pressing concern. These chemicals, commonly used to enhance the flexibility and appearance of plastics and personal care products, pose direct threats to human health through skin absorption. A team of researchers led by Dr. Pravindra Kumar at IIT Roorkee has made strides in addressing this issue. They successfully utilised an esterase enzyme from the soil bacterium Sulfobacillus acidophilus to break down diethyl hexyl phthalate (DEHP), a difficult-to-degrade plasticiser. This innovative research offers a promising approach to mitigating the environmental impact of plastics.

About Plasticisers

Plasticisers are additives used in a variety of products, including toys, shampoos, and food containers. They improve flexibility and durability but can leach into the environment. DEHP is one of the most prevalent high molecular weight phthalates, known for its persistence and potential health risks.

The Role of Esterase Enzyme

The esterase enzyme from Sulfobacillus acidophilus was identified for its ability to degrade DEHP. Researchers characterised this enzyme using X-ray crystallography, which revealed its active sites and degradation mechanisms. The enzyme breaks DEHP into mono-(2-ethylhexyl) phthalate (MEHP) and 2-ethyl hexanol, making it important player in plasticiser breakdown.

Research Methodology

The IIT Roorkee team cloned the genes of the EstS1 esterase enzyme into E. coli bacteria for large-scale production. This method allows for efficient enzyme production through aerobic culture. The researchers also employed sophisticated biochemical techniques to evaluate the enzyme’s efficiency in degrading DEHP.

Sequential Enzyme Action

In laboratory experiments, the team used a sequential enzyme approach. After the esterase enzyme breaks down DEHP into MEHP and 2-ethyl hexanol, a second enzyme, phthalate dioxygenase, converts the phthalate into intermediate compounds. Finally, these intermediates are transformed into protocatechuate, which enters the tricarboxylic acid cycle, ultimately producing carbon dioxide and water.

Future Prospects

The research team aims to integrate all five enzymes involved in the degradation process into bacteria. This integration will enhance the degradation efficiency, as the enzymes will remain active longer and operate continuously within the bacteria. The team is also exploring enzyme engineering to further expedite the breakdown of plasticisers.

1. DEHP stands for diethyl hexyl phthalate, a common plasticiser.
2. Sulfobacillus acidophilus is a soil bacterium used in this research.
3. MEHP is the primary breakdown product of DEHP degradation.
4. Comamonas testosteroni was previously isolated for phthalate breakdown.
5. Phthalate dioxygenase is crucial for converting phthalates into intermediates.

Environmental Impact

This research represents advancement in tackling environmental pollution caused by plasticisers. By breaking down harmful substances into harmless by-products, the IIT Roorkee team is paving the way for a cleaner future. The findings highlight the potential of bioremediation techniques in addressing one of the most pressing challenges of our time.

Month: Current Affairs - January, 2025

Category: Environment Current Affairs