Marine bacteria: A storehouse of novel compounds for biodegradation

Abstract

Marine environments, which cover over the two-thirds of the earth’s surface, constitute a great pool of diversified natural resources, as they comprise more than 95% of the biodiversity of the total environment. This broad biodiversity may be attributed to the broad spectrum of marine environments that are found on earth and can accommodate different types of life. Petroleum hydrocarbons are the most widespread contaminants within the marine environment. Pollution by hydrocarbons in marine environments may be the consequence of various natural (natural seepages) and/or anthropogenic activities (discharge during tanks and/or ships transportation and/or pipeline failures) as well as the chronic pollution (ships, harbors, oil terminals, freshwater run-off, rivers, and sewage systems). The increasing need to remedy adverse effects of anthropogenic activities on estuarine, coastal, and marine ecosystems has prompted the development of effective bioremediation strategies. In the natural environment, biodegradation of crude oil involves a succession of species within the consortia of the present. A consortium of many different bacterial species, with broad enzymatic capacities, is usually involved in oil degradation. The structurally diverse group of surfaceactive metabolites, synthesized by microorganisms, is classified as biosurfactants. The biosurfactants produced by some marine microorganisms are promising agents for bioremediation of hydrocarbons, particularly of oil pollution in marine environments. Because of the reduced surface and interfacial tensions exerted by these molecules, in both aqueous solutions and hydrocarbon mixtures, makes them potential candidates for enhancing oil recovery, and actually are under intense research, particularly for the bioremediation of the sea polluted by crude oil.