Review Article Petroleum-Degrading Enzymes: Bioremediation and New Prospects
R. S. Peixoto, A. B. Vermelho, and A. S. Rosado
Institute of Microbiology Paulo de G´es, Federal University of Rio de Janeiro, Rio de Janeiro 21 941902, Brazil o Correspondence should be addressed to R.S. Peixoto, firstname.lastname@example.org Received 15 April 2011; Accepted 27 May 2011 Academic Editor: Claudiu T. Supuran Copyright © 2011 R. S. Peixoto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Anthropogenic forces, suchas petroleum spills and the incomplete combustion of fossil fuels, have caused an accumulation of petroleum hydrocarbons in the environment. The accumulation of petroleum and its derivatives now constitutes an important environmental problem. Biocatalysis introduces new ways to improve the development of bioremediation strategies. The recent application of molecular tools to biocatalysis mayimprove bioprospecting research, enzyme yield recovery, and enzyme speciﬁcity, thus increasing cost-beneﬁt ratios. Enzymatic remediation is a valuable alternative as it can be easier to work with than whole organisms, especially in extreme environments. Furthermore, the use of free enzymes avoids the release of exotic or genetically modiﬁed organisms (GMO) in the environment.
Ourplanet hosts many diﬀerent environments. From the Arctic to the Antarctic, there are deserts, rainforests, abyssal regions, and many other places where diﬀerent forms of life can be found. Not all organisms can adapt and/or survive in diverse environments, but, instead, they inhabit speciﬁc environments according to their biotic and abiotic characteristics. However, microorganisms areeverywhere; they have colonised diverse environments for thousands of years, including those that, for most organisms, are considered “extreme.” In addition to colonising the environment, microorganisms colonise other organisms and are essential to life on our planet as we know it. Only a small proportion of bacteria are harmful. In fact, microorganisms are key components of food webs and biogeochemicalcycles and in the maintenance and survival of plants, animals, and other organisms through symbiotic relationships. Several microorganisms may be involved in the reactions of biogeochemical cycles, and in some cases they are the only biological agents capable of regenerating forms of elements needed for other organisms . Collectively, microorganisms have a great metabolic diversity, which allowstheir ubiquity. Because of their ubiquitous nature, the biotechnological potential of microorganisms is virtually endless, with many possible applications. One of these
applications is the utilisation of microorganisms or their enzymes in petroleum bioremediation approaches . Biocatalysis can provide alternative ways to improve petroleum bioremediation approaches ; the screening forenzymes for this purpose is necessary. This paper presents some enzymatic applications for the degradation of petroleum toxic compounds and a discussion about improvements that could be used in petroleum enzymatic bioremediation.
2. Petroleum-Polluted Sites
Petroleum is a heterogeneous mixture of hydrocarbons, including aliphatic (n-alkanes), alicyclic, and aromatic hydrocarbons (i.e.,polycyclic aromatic hydrocarbons), which varies in compositional and physical properties accor-ding to the reservoir’s origin . These hydrocarbons are organic compounds containing carbon and hydrogen, which are highly insoluble in water. Microorganisms can either degrade or produce hydrocarbons , depending on the presence of certain metabolic pathways, speciﬁc to each function in the environmental...