A new scaffold-bacteria-based system for bioremediation of oil contaminated water

Abstract

Bioremediation is a promising non-invasive and cost-effective technology that uses (micro)organisms to degrade or remove hazardous environmental pollutants. New methods are needed to enhance and optimize natural biodegradation, such as the use of carrier materials that could improve survival and catalytic activity of the biodegraders. In this study, we developed a bioremediation system based on a new 3D polycaprolactone-based scaffold and hydrocarbon(HC)-degrading bacteria to clean (sea)water contaminated by crude oil and its derivatives. Scaffold biopolymers are biodegradable, produced in the melt, i.e. at low cost and without the use of toxic solvents. They can be available in large quantities and endowed with a marked lipophilicity1. The bioremediation efficiency of our system was tested on crude oil and n-alkanes using two highly performant HC-degraders: the marine hydrocarbonoclastic model strain Alcanivorax borkumensis SK22 and the soil long-chain n-alkane degrader Nocardia sp. strain SoB3. A high capacity of adhesion and proliferation of bacterial cells within the whole three-dimensional structure was observed using scanning electron microscopy. The bacterial degradation ability of HC-embedded scaffold was evaluated by GC-FID analysis. Total oil HC degradation rates of 50% and 40% of were observed after 6 days incubation, for Nocardia and Alcanivorax, respectively; rates of biodegradation of 90% (Nocardia) and 60% (Alcanivorax) were observed for n-alkanes after the same incubation period. The degrading ability of the scaffold-bacterial cells system was compared whit that of free-living cells. The use of this bioremediation system may lead to a better interaction between the hydrophobic substrate and the bacterial cells, increasing the bacterial degradation ability. 1 Scaffaro R., et al.,submitted. 2Yakimov M.M. et al., (1998) IJSEM 48: 339-348. 3Quatrini P. et al., (2008) JAM 104: 251–259