Effect of nutrients on the microbial degradation of hydrocarbon by a marine microorganism, Pseudomonas sp.

Abstract

In order to improve the microbial degradation rate of n-tetradecane by Pseudomonas sp. in enriched sea water, the growth mediums which consisted of various nutrients as nitrogen and phosphorus source were investigated experimentally. It was shown that the seawater medium enriched by NH₄NO₃, K₃PO₄ and yeast extract was most appropriate to degrade n-tetradecane by Pseudomonas sp.
When NH₄NO₃/K₃PO₄ ratio was maintained at 10, the relation between the biodegradation rate of oil, r_m mg-oil l^-1h^-1, and the nutrient concentration, S mg-NH₄NO₃l^-1, was in good agreement with the following equation.
r_m=max·S/K_m+S
where (r_m) _max was the maximum r_m and K_m was the saturate constant. For the initial concentration of oil, 153 mg l^-1, (r_m) _max was determined to be 4.9 mg-oil l^-1h^-1 and K_m was 94 mg-NH₄NO₃ l^-1.
Furthermore rapid degradation of the oil was suggested to be a result of the enhanced growth rate of Pseudomonas sp., hence the increased production of emulsifier in the improved medium.