Quantitative Determination of Microbial Oil Degradation and Of Oil Absorption by a New Oil-Binding System in a Baltic Sea Mesocosm Experiment

Abstract

ABSTRACT In this study, a novel oil-binding system for marine application was developed within the joint research project “BIOBIND” (“Airborne clean-up of oil pollution at sea with biogenic oil binders”). The system's components include oil-absorbing solids, made of biogenic and biodegradable wood-fiber, that can be dropped from an aircraft and subsequently recovered either at sea or along the coast. The binder-based system was tested together with oil-degrading microbial communities previously isolated from coastal water samples of the Baltic Sea. In a first attempt at a meso-scale setup, mesocosms containing different combinations of seawater, oil binders, crude oil, and oil-degrading bacteria were established. These experiments sought answers to the following questions: (1) How does the microbial community isolated from the Western Baltic Sea react to oil entries? (2) What happens to the crude oil? (3) How efficient is the oil absorption capacity of the developed binders? Microbial activity was monitored by measuring the oxygen, phosphate, and ammonia contents of the mesocosms. Weight loss of the whole crude was estimated using a gravimetric method. In one of the mesocosms, the selected inoculum degraded around 25 % of the added crude oil. In another, in which the absorption efficiency of the oil binders was examined, more than 98 % of the crude oil was absorbed. Further molecular details on the fate of the oil were obtained using gas chromatography with a flame ionization detector and mass spectrometry to quantify alkanes and polycyclic aromatic hydrocarbons, respectively; both were efficiently degraded by the selected inoculum. The oil absorption and oil-degrading capabilities of a system consisting of oil binders and oil-degrading microbial communities at the meso-scale was shown. These promising preliminary tests recommend its further development for use in responding to small- and medium-size oil spills in near-coastal shallow-water areas.