抄録
A new ice-nucleating bacterium, KUIN-3, was isolated from strawberry leaves. Strain KUIN-3 was identified as Erwinia uredovora from its taxonomical characteristics. The extracellular ice-nucleating matter (EIM) produced by strain KUIN-3, was purified to apparent homogeneity by ultra filtration, sucrose density-gradient ultracentrifugation, and gel filtration. The purified EIM was spherical matter (about 250 nm) by examination using a transmission electron microscope. The ice-nucleating activity from the EIM was equal to that of the cells in this strain. It was demonstrated that the components of the EIM were lipid, protein, saccharide and polyamine. The enzyme treatments by protease K, α-mannosidase, β-galactosidase, phospholipase C, and diamine oxidase decreased the activity of the EIM as well as of the cells. The results suggested that polyamine was the most important component of the EIM. The application of the ice nucleation activity of the EIM to the freezing-foods was attempted.
