A lipase-and biosurfactant-producing, Gram-positive, aerobic and coccal bacterium designated as CH1-8 was isolated from Thai fermented fish. It grew optimally at 37 C, pH 7.0, and in the presence of 0-5%, w/v NaCl. The results of phenotypic and chemotaxonomic properties including phylogeneitc tree analysis confirmed that it was belonged to the genus Stayphylococus. The16S rRNA gene sequence analysis revealed that strain CH1-8 was closely related to Staphylococcus xylosus ATCC 29971T (99.11%), therefore it was identified as Staphylococcus xylosus. This strain gradually degraded various types of oils, sunflower oil, palm oil, soybean oil and rice bran oil, including cooking oil. During cultivation at room temperatue for 35 days, lipase and biosurfactant acitivities of strain were 2 units/ml and 52 mN/m, respectively while the cleavage products were almost completely consumed. The maximal percentage of cooking oil hydrolysis by strain CH1-8 was 90% in the absence of NaCl and 60% in the presence of 10%, (w/v) NaCl. Therefore, the quality of wastewater from household will environmentally accepted after treated with strain CH1-8.
Key words: Staphylococcus xylosus, lipase, biosurfactant, oil-degradation
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