Ghodke_2021_Environ.Microbiol__

The carboxylesterases (EC 3.1.1.x) are widely distributed and form an important yet diverse group of hydrolases catalyzing the ester bond cleavage in a variety of substrates. Besides acting on plant cell wall components like cutin, tannin and feruloyl esters, they are often the first line of defense to metabolize drugs, xenobiotics, pesticides, insecticides, and plastic. But for the promiscuity of some carboxylesterases and cutinases, very few enzymes act exclusively on aromatic carboxylic acid esters. Infrequent occurrence of aromatic carboxylesterases suggests that aromatic carboxylesters are inherently more difficult to hydrolyze than the regular carboxylesters because of both steric and polar effects. Naturally occurring aromatic carboxylesters were rare before the anthropogenic activity augmented their environmental presence and diversity. An appraisal of the literature shows that the hydrolysis of aromatic carboxylic esters is a uniquely difficult endeavor and hence deserves special attention. Enzymes to hydrolyze such esters are evolving rapidly in nature. Very few such enzymes are known and they often display much lower catalytic efficiencies. Obviously, the esters of aromatic carboxylic acids, including polyethylene terephthalate waste, pose an environmental challenge. In this review, we highlight the uniqueness of aromatic carboxylesters and then underscore the importance of relevant carboxylesterases. This article is protected by copyright. All rights reserved.