title: Biodegradation of aromatic compounds: current status  and opportunities for biomolecular approaches.
abstract: Biodegradation can achieve complete and cost-effective elimination of aromatic pollutants through harnessing diverse microbial metabolic processes. Aromatics biodegradation plays an important role in environmental cleanup and has been extensively studied since the inception of biodegradation. These studies, however, are diverse and scattered; there is an imperative need to consolidate, summarize, and review the current status of aromatics biodegradation. The first part of this review briefly discusses the catabolic mechanisms and describes the current status of aromatics biodegradation. Emphasis is placed on monocyclic, polycyclic, and chlorinated aromatic hydrocarbons because they are the most prevalent aromatic contaminants in the environment. Among monocyclic aromatic hydrocarbons, benzene, toluene, ethylbenzene, and xylene; phenylacetic acid; and structurally related aromatic compounds are highlighted. In addition, biofilms and their applications in biodegradation of aromatic compounds are briefly discussed. In recent years, various biomolecular approaches have been applied to design and understand microorganisms for enhanced biodegradation. In the second part of this review, biomolecular approaches, their applications in aromatics biodegradation, and associated biosafety issues are discussed. Particular attention is given to the applications of metabolic engineering, protein engineering, and "omics" technologies in aromatics biodegradation.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore.
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Karthiga
authors.initials: K
authors.lastname: Nagarajan
authors.forename: Kai-Chee
authors.initials: KC
authors.lastname: Loh
mesh_terms: D001419:Bacteria / Q000166:cytology / Q000378:metabolism*; D001554:Benzene / Q000378:metabolism; D001555:Benzene Derivatives / Q000378:metabolism; D001673:Biodegradation, Environmental; D018441:Biofilms; D004785:Environmental Pollutants / Q000302:isolation & purification; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism; D010573:Pesticide Residues / Q000378:metabolism; D010933:Plankton / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism; D014050:Toluene; D014992:Xylenes / Q000378:metabolism
chemical_list: D001555:Benzene Derivatives; D004785:Environmental Pollutants; D006841:Hydrocarbons, Aromatic; D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D011084:Polycyclic Aromatic Hydrocarbons; D014992:Xylenes; D014050:Toluene; D011078:Polychlorinated Biphenyls; D001554:Benzene; C004912:ethylbenzene