IMPROVEMENT OF IMMOBILIZATION CONDITIONS FOR BIODEGRADATION OF FLOATING OIL BY A BIO-SYSTEM CO-IMMOBILIZING MARINE OIL-DEGRADING YEAST CANDIDA SP AND NUTRIENTS

A new type of the biodegradable immobilizing carrier was developed for the biodegradation of oil spilled on the sea surface, and the physica l properties of the carrier and its effectiveness in oil-biodegradatio n was evaluated. The carrier was formed by mixing chicken egg as a foa ming agent and sodium alginate as a basic support at a ratio of about 20:1. Chemical cross-linking of protein in the chicken egg by glutaral dehyde improved the oil absorbability and the buoyancy of the immobili zing carrier. The ultimate strength of the carrier increased with incr eased concentration of the glutaraldehyde. The viability of the marine oil-degrading yeast Candida sp. (strain S10W5) immobilized in the car rier was not affected by the glutaraldehyde treatment. As immobilized nutrients, the combination of nine parts of crotonyliden-diurea and on e part of MgHPO4 was most effective. By using the carrier immobilizing the marine oil-degrading yeast and the nutrients, a mixture of n-alka nes (C-12-C-18) was degraded to less than 20% of its initial concentra tion in 14 d at 20 degrees C.