INVOLVEMENT OF CA-2+ IN THE FLOCCULATION OF KLUYVERA-CRYOCRESCENS KA-103

Kluyvera cryocrescens KA-103 showed a dispersed growth in Ca2+-free Polypepton medium, but formed flocs on addition of a sufficient concentration of Ca2+ to the bacterial cell suspension. Therefore, calcium adsorption properties and flocculation conditions were investigated using bacterial cells cultured in the Ca2+-free Polypepton medium. The bacterium required 1.5 mM Ca2+ or more for good flocculation (F>90%), but a cooperative effect of Na+ and Ca2+ on good flocculation was observed at lower concentrations of Ca2+. The Langmuir adsorption isotherm was used to describe the adsorption of Ca2+ by the bacterial cells. © 1990.