IIT Roorkee Develops Bacterial Enzyme-Based Solution to Degrade Plasticizers

IIT Roorkee Develops Bacterial Enzyme-Based Solution to Degrade Plasticizers

Sub : Sci

Sec: Msc

Why in News

• Researchers at IIT Roorkee have developed a method using bacterial enzymes to degrade high molecular weight plasticizers like diethyl hexyl phthalate (DEHP). This breakthrough aims to combat the increasing environmental and health risks posed by plasticizers.

What are Plasticizers?

• Chemicals added to plastics and personal care products to improve flexibility and shine.
• Commonly found in baby toys, shampoos, soaps, and food containers.
• Plasticizers can be absorbed through the skin, posing carcinogenic risks.
• Their prevalence in the environment has been rising at an alarming rate.

Research at IIT Roorkee:

• They utilized an enzyme, esterase, derived from the soil bacterium Sulfobacillus acidophilus to degrade DEHP plasticizer.
• This enzyme demonstrated the ability to break down high molecular weight phthalate plasticizers, previously considered difficult to degrade.
• The esterase enzyme was structurally characterized using X-ray crystallography to identify active sites and understand the degradation mechanism.
• Additional biochemical and biophysical approaches were employed to study enzyme efficiency.
• Enzymes Used in Sequence:
  • Sulfobacillus acidophilus: Esterase enzyme for breaking DEHP into MEHP and 2-ethyl hexanol.
  • Comamonas testosteroni: Enzymes for further degradation:
    • Phthalate dioxygenase converts phthalate into intermediate compounds.
    • Phthalate decarboxylase converts intermediates into protocatechuate.
    • The bacteria’s tricarboxylic acid cycle then converts protocatechuate into water and carbon dioxide.
  • Degradation Process:
    • The enzyme breaks down DEHP into two products:
      • Mono-(2-ethylhexyl) phthalate (MEHP)
      • 2-ethyl hexanol
    • These products can be further degraded into water and carbon dioxide using a sequence of enzymes.
    • Gene Cloning: The genes for the esterase enzyme were cloned into coli bacteria for large-scale enzyme production. Enzymes produced through aerobic culture were effective for degradation.
    • Integration into Bacteria: Integrating enzymes into bacteria ensures prolonged activity and continuous degradation. Eliminates the need for fresh enzyme batches, making the process efficient.

Diethyl Hexyl Phthalate (DEHP): A high molecular weight plasticizer used to enhance flexibility in plastics, known for its carcinogenic effects.

Esterase: An enzyme that catalyses the breakdown of ester bonds, crucial for degrading plasticizers like DEHP into simpler compounds.

Soil Bacterium Sulfobacillus acidophilus: A microorganism producing esterase enzyme, effective in degrading high molecular weight plasticizers.

X-ray Crystallography: A technique used to determine the three-dimensional structure of molecules, identifying active sites in enzymes like esterase.