title: Formation of stable foam by the cells and culture supernatant of Gordonia (Nocardia) amarae.
abstract: Gordonia amarae is the cause of foaming activated sludge. In this study, the mechanism of foam formation by G. amarae SC1 was investigated. A liquid culture of SC1 cells generated a stable foam when shaken reciprocally. This foam formation was dependent on the presence of both bacterial cells and culture supernatant. A high-molecular-weight fraction (Mw>10000) of the supernatant was capable of emulsifying n-hexadecane in addition to exhibiting foaming activity, indicating that it contains a surface-active substance(s). The bacterial cells showed a high affinity to hexadecane. This hydrophobic cell surface property might be involved in the attachment of cells to air bubbles to generate a stable foam. The results demonstrated the participation of cells and the extracellular biosurfactant in the formation and stabilization of foam in G. amarae SC1 culture.
authors.affiliation: Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan. iwahori@sea.u-shizuoka-ken.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Iwahori
authors.forename: T
authors.initials: T
authors.lastname: Tokutomi
authors.forename: N
authors.initials: N
authors.lastname: Miyata
authors.forename: M
authors.initials: M
authors.lastname: Fujita