Extracellular product of Nocardia amarae induces bacterial cell flocculation

The fact that Nocardia amarae YK1 produced a bacterial flocculation-inducing substance (designated as FIX) was discovered. FIX had a function of flocculating proliferous cells. FIX-induced flocculation was inhibited by making cells resting, but not completely by adding chloramphenicol. FIX worked widely on Gram-positive to -negative bacteria. In the presence of FIX, Achromobacter cycloclastus IAM1013, Acinetobacter calcoaceticus IAM1517, Bacillus subtilis IAM1069, Escherichia coli C600-1, E. coli IAM1239, Flavobacterium lutescens IAM1667, Klebsiella pneumoniae IAM1102, Micrococcus luteus IAM1313 and Pseudomonas putida IAM1002 formed flocs. B. cereus IAM1029, however, exhibited no flocculation.