Growth of Fungus Isolated from Sludge at Bottom of Ship's Fuel Tank

Growth of a fungus, which was isolated from the sludge at the bottom of a ship's fuel tank for Marine diesel oil, was examined. A lot of sludge had been stacked on the wire-mesh filter in the fuel strainer. In this ship, the commercially available dispersant, YUNIC #555D, was being used continuously to reduce the sludge formation in Marine diesel oil. The microscopic observation of the sludge revealed the mycelia of the fungus. The volume concentration of the dispersant in the sampled fuel oil containing sludge was estimated to be 1/300- 1/400, which was 25-67 times higher than that recommended by the company. This dispersant might have contributed to an increase in the growth of the isolate in Marine diesel oil. Hence we examined the additional effect of the dispersant on the growth of the isolate in Marine diesel oil. It was found that the isolate could grow in Marine diesel oil alone. Growth repression of the isolate, however, was observed even in the presence of 117100 of the dispersant as a final volume concentration. We examined another dispersant, SPA·LAZAE® that did not have any effect on the growth of the isolate.