The aim of this study was to examine the effects of lipophilic fertilizers (uric acid and lecithin) on the degradation of crude oil hydrocarbons in the oil-spilled coast. An area of oil-spilled coast was selected and dived into tidal and non tidal zones. These zones were further divided into fertilizer amendment and non-amendment zones. Lipophilic fertilizers were spread into fertilizer amendment zones monthly. Degradation of crude oil in these test zones were investigated by measuring concentration of the total hydrocarbon, NH4+-N, NO3--N, total phosphorus, number of petroleum degraders, and microbial dehydrogenase activity in sands or sediments in these zones monthly. Although there were no any trend in the concentration of NH4+-N, NO3--N, and total phosphorus, concentration of total hydrocarbon in these zones decreased during the test period. The number of petroleum degrader reached the highest in the beginning of June in non tidal-fertilizer amendment zone, while in the beginning of July in the tidal-fertilizer amendment zones. The number of petroleum degraders did not change much in non-fertilizer amendment zones. The number of petroleum degraders in these zones all decreased sharply after July. Dehydrogenase activity increased from May to July and then decreased in sand/sediment of all these zones. However, dehydrogenase activity in sand/sediment was much higher in fertilizer-amended than in fertilizer-non amended zones. Based on these results, we know that fertilizer amendment increased the number of petroleum degraders and microbial activity, and enhanced crude oil removal. In this study, we also used Bushnell-Haas broth to enrich and isolate petroleum degraders from sand/sediment of these oil-spilled zones. We found there was not much difference in the microbial community of tidal and non tidal zones. Amendment of fertilizer increased species of petroleum degraders in sediments but not in sands. We isolated 15 strains. 11 strains, e.g. Alcanivorax dieselolei, Acinetobacter venetianu, Bacillus firmus, Candida viswanathii, Dietzia maris, Novosphingobium pentaromativorans, Pseudomonas pseudoalcaligenes, P. stutzeri, Tistrella mobilis, Cellulosimicrobium cellulans, Brevibacterium iodinum can degrade crude oil. Four strains, e.g. Oceanbacillus iheyensis, Halomonas venusta, Shewanella algae, Staphylococcus saprophyticus can not degrade crude oil. However, using consortia of these 11 petroleum-degrading bacteria for on site bioremediation did not get good results. Various environmental factors such as weather, tidal might affect these results. Further works are needed to prepare better consortia for bioremediation.

Crude oil、Dehydrogenase activity、Lipophilic fertilizers、The Most Probable Number Method