Effect of growth conditions on the activity of Kluyveromyces lactis killer toxin

ABSTRACT

A study has been made of the relationship between incubation temperatures [[20 and 30'C] at different pH values [4,6and 8] and different carbon sources [maltose, mannitol and glycerol] on the growth and toxin production by Kluyveromyces lactis [y-1140]. The highest level of toxin production was observed nearly at a temperature of 30°, when maltose was used as the carbon source rather than mannitol and glycerol. Also the inhibitory effects of K.lactis Killer toxin against sensitive yeasts cells was significantly enhanced when plate assays were performed in media at pH 6 rather than at both pH 4 and pH Sand at an incubation temperature of 30° rather than at 20°. However the interference of K.lactis killer toxin with some test yeasts toxin could not be ignored