Effect of Temperature on Hydrocarbon Bioremediation in Simulated Petroleum-Polluted Seawater Collected from Tokyo Bay

This study focused on the effect of temperature on biological removal of petroleum hydrocarbons. Seawater samples were collected from two stations in Tokyo Bay seasonally, and were made into petroleum-polluted seawater by adding mixture of n － alkanes in a fixed concentration in laboratory. A 28 days of bioremediation incubation experiment was carried out with and without additional nutrients supplement in each season, and the remained hydrocarbons during incubations were measured by GC － MS. alkB gene, the functional gene responsible for alkane degradation, was also recorded throughout the incubation. Our results showed that bioremediation efficiency of petroleum hydrocarbon was highest in summer, followed by spring, autumn, and winter respectively. Alkanes with as much as 34 carbon atoms can be significantly degraded within 28 days of incubation in summer, and in contrast, no obvious degradation can be recognized in winter regardless of the number of carbon atoms. N － alkanes degradation efficiency was generally associated with, but not necessarily correlated to the copy number of alkB gene.