Researchers at the Indian Institute of Technology (IIT) Roorkee discovered a 3D structure of a bacterial enzyme that can aid the faster breakdown of plastic, said a press release. The research was spearheaded by Prof Pravindra Kumar with five associates at the Department of Biosciences and Bioengineering at IIT Roorkee.
The team identified all the enzymes responsible for phthalate and terephthalate degradation in Comamonas testosteroni KF1, a type of microbe, that would help in faster degradation of plastics and plasticisers, which are considered non-biodegradable. Apprising of the research results, Prof Pravindra Kumar, Department of Biosciences and Bioengineering at IIT Roorkee, highlights, "The global plastic pollution has become the most pressing environmental issue. And recent studies on enzymes degrading polyethylene terephthalate type of plastics into terephthalate (TPA) show some potential in tackling this. Also, research from the last decade has discovered terephthalate dioxygenase (TPDO), as being responsible for initiating the enzymatic degradation of TPA in a few Gram-negative and Gram-positive bacteria. Therefore, building on this, the team members have determined the crystal structure of TPDO from Comamonas testosteroni KF1 and revealed that this enzyme can help degrade non-biodegradables".
Phthalate, a substance that hinders the endocrine system in living beings and a potential carcinogen, found in plastics is degraded by a variety of bacteria. This degradation is initiated by phthalate dioxygenase (PDO), a Rieske oxygenase (RO) that catalyzes the dihydroxylation reaction. Further, ROs are a family of enzymes best known for catalyzing the first step in the catabolism of toxic aromatic compounds via regio- and stereospecific cis-dihydroxylation and have been the focus of extensive investigation because of their potential use in the biodegradation of persistent and toxic aromatic compounds.
Talking about the findings, Prof Ajit K Chaturvedi, Director, IIT Roorkee, said, "Toxic phthalates are detrimental to the environment. These results provide insights into a pollutant-degrading enzyme. The results facilitate the engineering of this enzyme for bioremediation and biocatalytic applications".
The study on phthalate dioxygenase is published in "Journal of Biological Chemistry", while on terephthalate dioxygenase will be published in the February edition of "Journal of Bacteriology".
Jai Krishna Mahto is the lead author of this work. Other Scientists, Neetu, Ms Monica Sharma, Bhairavnath Waghmode, Monica Dubey, Prof B P Vellanki, Prof Debabrata Sircar, Prof A K Sharma, and Prof Shailly Tomar were part of the team who contributed immensely to this work.