A study of a bacterial immobilization substratum for use in the bioremediation of crude oil in asaltwater system

Abstract

N.G. WILSON AND G. BRADLEY. 1997. An immobilization matrix, Drizit, was examined for use in the bioremediation of oil in a saltwater system. The support was examined by scanning electron microscopy, cell-loading capacity, absorption of Ekofisk crude oil, the effect on cell recoverability of drying Drizit-immobilized cells at room temperature, 55°C or freeze drying and storage for up to 3 months, and the capability of immobilized Pseudomonas fluorescens to enhance biodegradation of petrol (Slovene diesel) in a saltwater system. Results showed that Drizit is an ideal immobilization substratum for use in bioremediation, and the substratum was found to have a good cell-loading capacity (3.75 mg protein g -1 substratum) and a high absorbency of oil (7.49 g Ekofisk g -1 substratum). After drying the immobilized cells at room temperature, 55°C or freeze drying and subsequent storage, cells were not recoverable after 2 weeks, 1 week or 2 months, respectively, and a significant decrease was seen in the number of cells recovered after drying and I week's storage in all cases. Enhanced biodegradation of C 13 -C 18 pristane and phytane, in petrol (Slovene diesel) occurred with the immobilization of Ps. fluorescens to Drizit. An average degradation of 73.8% occurred in the immobilized system in comparison with the free system which resulted in an average degradation of 39.8%. When the two systems were supplemented with nitrates and phosphates, degradation in the free supplemented system increased to an average of 72.4%. However, no significant difference in biodegradation was found between the immobilized system and the immobilized system supplemented with nitrates and phosphates which achieved an average degradation of 74.15%.