Selective Stimulation of Aromatic Compound Degradation by the Indigenous Marine Bacterium Cycloclasticus for Bioremediation of Oil Spills in the Marine Environment

Abstract

S-2 EPS, an extracellular polysaccharide produced by Rhodococcus rhodochrous S-2, is a functional biopolymer that increases the organism’s organic solvent tolerance. We previously demonstrated that addition of S-2 EPS and minerals to oil-contaminated seawater enhanced the degradation of an aromatic fraction (AF) of Arabian light crude oil by Cycloclasticus, a polycyclic aromatic hydrocarbon (PAH)-degrading indigenous marine bacterium, and stimulated its growth in AF-contaminated seawater. Moreover, Cycloclasticus growth and PAH degradation were selectively activated by the association of S-2 EPS with Cycloclasticus cells. In this chapter, the effects of S-2 EPS on the growth and PAH degradation activity of Cycloclasticus in hydrocarbon-degrading marine bacterial consortia are summarized. S-2 EPS regulates the interaction between living bacteria and oils, and because it selectively stimulates degradation of aromatic compounds by the indigenous marine bacterium Cycloclasticus, S-2 EPS is useful for bioremediation of oil spills in the marine environment.