醫學檢驗暨生物技術學系WEI, YU-HONGYU-HONGWEILAI, HSIN-CHIHHSIN-CHIHLAICHEN, SHAN-YUSHAN-YUCHENYEH, MAO-SONGMAO-SONGYEHCHANG, JO-SHUJO-SHUCHANG2009-01-202018-07-062009-01-202018-07-062004http://ntur.lib.ntu.edu.tw//handle/246246/105299Serratia marcescens SS-1 and its SpnR-defective isogenic mutant, SMDeltaR , produced an extracellular surfactant able to decrease surface tension of water from 72 to 37 dyne cm(- 1) (SMDeltaR strain) and to 45 dyne cm(-1) (SS-1 strain). The biosurfactant also emulsified kerosene and diesel with a maximum emulsion index of 77% ( diesel and kerosene) for the SMDeltaR strain, and 72% ( kerosene) and 40% ( diesel) for the SS-1 strain. Deletion of spnR gene appeared to enhance biosurfactant production. Model simulations suggest that biosurfactant production by the two strains was growth- associated. The SMDeltaR strain had a yield coefficient of 22 - 32 % g dry cell(-1), which is 32 - 50% higher than that of the SS-1 strain.en-USbiosurfactantemulsificationquorum sensingSerratia marcescenssurface tension