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.

Aerobic Degradation of Petroleum Components by Microbial Consortia

“…Petroleum compounds differ in their susceptibility to microbial attack and generally degrade in the following order of decreasing susceptibility [37]: n-alkanes > branched alkanes > low molecular weight aromatics >cyclic alkanes, > polycyclic aromatic hydrocarbons > polar compounds. Although many of these compounds can be relatively easily degraded under soil and fresh water environments [3,12] and low salinity marine habitats [13][14][15][16]. Biodegradation rates have been shown to be highest for the saturates, followed by the light aromatics, with high-molecular-weight PAHs and polar compounds (resins and asphaltenes) exhibiting extremely low rates of degradation or may not be degraded at all [38][39][40].…”

“…Petroleum compounds such as alkanes, benzene, toluene, ethyl benzene, and xylenes (BTEX) and some polycyclic aromatic hydrocarbons (PAHs) are biodegradable under the proper environmental conditions [3,12] and low salinity marine habitats [13][14][15][16]. However, higher molecular PAHs, polycyclic aromatic sulphur heterocyclics (PASHs), methyl tertiary butyl ether (MTBE), gasoline additive and other components of petroleum products may be recalcitrant to biodegradation.…”

Implications of Benzoate Induced Alterations in Cell Morphology and Physiology in Pseudomonas aeruginosa TMR2.13 for Potential Application in Bioremediation and Monitoring Approaches

“…Hydrocarbon contamination particularly that derived from petroleum products and other anthropogenic activities is a major cause of concern in the marine environment and has therefore garnered interest in bioremediation studies [1][2][3][4]. Environments rich in hydrocarbons particularly coastal and estuarine ecosystems generally have a high nitrate load [5].…”

Impacts of produced water origin on bacterial community structures of activated sludge

“…The new compositionfunction sludge was achieved by bacterial community dispersal and assembly. The genera retrieved from both clone libraries such as Pseudoalteromonas, Marinomonas, Novosphingobium and Flavobacterium, which are regarded as the PAH degraders referred to pure cultures, were always retained in sludge (Cao et al, 2009). Most of the other species were endangered by the new environmental conditions and replaced by influent-sourced bacteria.…”