Molecular and cellular fundamentals of aerobic cometabolism of trichloroethylene

Citation
Dj. Arp et al., Molecular and cellular fundamentals of aerobic cometabolism of trichloroethylene, BIODEGRADAT, 12(2), 2001, pp. 81-103
Citations number
124
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Biotecnology & Applied Microbiology
Journal title
BIODEGRADATION
ISSN journal
0923-9820 → ACNP
Volume
12
Issue
2
Year of publication
2001
Pages
81 - 103
Database
ISI
SICI code
0923-9820(2001)12:2<81:MACFOA>2.0.ZU;2-O
Abstract
Cometabolism recognizes that microorganisms can transform non-growth-suppor ting substrates. The term "cometabolism'' was first introduced over 30 year s ago and has been redefined, criticized, and used widely ever since. In th is review we have examined the aerobic cometabolism of chlorinated solvents , with a particular emphasis on the cometabolism of trichloroethylene. Mono oxygenases or dioxygenases with relaxed substrate ranges initiate these tra nsformations. The physiological role of the oxygenases is to initiate the m etabolism of growth-supporting substrates (e.g., methane, propane, butane, toluene, ethylene, and ammonia). Diverse enzymes catalyze these oxidative r eactions with chlorinated solvents. Synthesis of most of these enzymes is i nduced by the presence of the growth-supporting substrate and is largely re gulated at the level of gene transcription. The genes that code for a given oxygenase are usually clustered together in a single operon and often shar e homology with counterparts that code for the subunits of related oxygenas es in other bacteria. During cometabolism the growth-supporting and non-gro wth-supporting substrates can both bind to the oxygenase. Transformation of chlorinated solvents by these enzymes presents the cell with a new set of compounds. Some of these compounds are toxic to the cells, others are stabl e products that are expelled from the cell, and in a few cases the cells ut ilize the products. The combined effects of cometabolism can have a profoun d influence on a cell.