Petroleum oil removal by immobilized bacteria-support system

Abstract

Petroleum oil spills at sea are a major environmental concern. The development of new technologies to remediate oil polluted sea water is thus of great importance. In this work, a co-culture of two hydrocarbon degrading strains (Pseudomonas monteilii P26 and Gordonia sp. H19) was immobilized in polyurethane foam (PUF) and used at microcosm scale for petroleum oil removal from artificial sea water at different temperatures. The immobilization was carried out using corn steep liquor (10% v/v) as a low cost culture medium. The immobilized biofilm was quantified by viable cell counts of the two strains. Approximately 108 CFU/g support of both strains were obtained. The oil removal of the bacteria immobilized on PUF and the PUF alone was similar (nearly 50%) at 4 °C and 15 °C in 7 days. At 30 °C the oil removal was 80% for the immobilized cells-PUF system and 60% for the PUF alone in the same time. The sorbed oil on PUF was also quantified: when adding the quantity of oil sorbed by the sterile PUF and the quantity that remainined in the water, the initial quantity of oil minus the oil loss by volatilization was obtained. On the other hand, in the case of the immobilized cells-support system, the sum of the remaining and sorbed oil was less than the initial oil after volatilization. This indicates that oil removal was achieved due to a combined sorption and biodegradation effect of the system comprised by P26-H19-PUF. Further research will focus on the storage capability of the immobilized biomass and on oil removal from soil.