Enhanced degradation of petrol (Slovene diesel) in an aqueous system by immobilized Pseudomonas fluorescens

The rate of degradation of n-alkanes C-12-C-18, in petrol (Slovene diesel) in an aqueous system, by free and immobilized Pseudomonas fluorescens in shaking flasks was investigated. Cells were immobilized to a biosupport, Biofix, and a biosorbant, Drizit. Analysis of cellular growth of the free and immobilized bacteria over 8 d of incubation with diesel as the sole carbon source, show-ed a reduction in the lag phase in the immobilized cultures in comparison to the free system. The free system degraded 52.3% of C-12 and 11.6% of C-13, but C-14-C-18 were not degraded. In comparison to the free system and diesel which had not been exposed to experimental conditions (unexposed), the immobilized systems degraded significantly more of C-13-C-18. Biofix-immobilized cells degraded 14.8% of C-12 and an average of 53.5% of C-13-C-18. Drizit-immobilized cells degraded 24.5% of C-12, 52.4% of C-13 and an average of 91.2% of C-14-C-18. This study shows the successful use of immobilized bacteria technology to enhance the degradation of diesel in an aqueous system.