Use of esterase enzyme in the decomposition of plasticizers

Why in the news?

Researchers at Indian Institute of Technology Roorkee (IIT Roorkee) have successfully used ‘esterase enzyme’ produced by soil bacteria Sulfobacillus acidophilus for the decomposition of Diethyl Hexyl Phthalate (DEHP) plasticizer.

Mechanism of Esterase Enzyme:

• Esterase enzyme catalyzes the decomposition of DEHP plasticizer by remaining active for about a month.
• This enzyme decomposes DEHP plasticizer into two by-products:
  • Mono-(2-ethylhexyl) phthalate
  • 2-ethyl hexanol
• It converts high molecular weight phthalate plasticizer into water and carbon dioxide. 
• Esterase enzymes break down esters into alcohols and acids through a chemical reaction called hydrolysis. Esterases are found in animals, plants and microorganisms and have many different biological functions:
  • As biocatalysts
  • For drug hydrolysis
  • To impart characteristic flavors to wines
  • In insect defense system
    • Esterases are an important part of the xenobiotic defense system of insects.
  • In the diagnosis of lower urinary tract infections
• For large-scale production of this enzyme, researchers cloned the gene for the EstS1 esterase enzyme into E. coli bacteria and produced the enzyme on a large scale through aerobic culturing.
  • Aerobic culture can be used for a variety of purposes, including:
    • • Detection and isolation of pathogens
      • Water treatment
      • Cultivation of methane-producing archaea

About Plasticizers

• Plasticizers are chemicals added to plastics and personal care products to increase their flexibility and gloss.
• They are commonly found in items such as children's toys, shampoos, soaps, and food containers.
• Plasticizers can be absorbed through the skin, making them a direct threat to human health.
• Other examples of plasticizers besides DEHP are:
  • Phthalate esters: diisononyl phthalate (DINP), bis(2-propylheptyl) phthalate (DPHP), diisodecyl phthalate (DIDP), diisondecyl phthalate (DIUP) and ditridecyl phthalate (DTDP)
  • Glycerin
  • Castor oil