The mechanism of stabilization of actinomycete foams and the prevention of foaming under laboratory conditions

Cultures ofNocardia amarae give rise to cell-stabilized foams in a laboratory scale foaming apparatus. The organism produces a surfactant and the cells are very hydrophobic; factors which, in terms of froth flotation theory, are essential for foam production and transport of the cells from the aqueous to the bubble phase. The addition of montmorillonitic clay to the culture prior to foaming prevents foam stabilization. The results obtained suggest the formation of a salt-dependent, reversible, bacterium-montmorillonite complex which prevents transport of cells to the bubble phase.