Short communication - Production and characteristics of Debaryomyces hansenii killer toxin

The optimal conditions for the production of the killer toxin of Debaryomyc es hansenii CYC 1021 have been studied. The lethal activity of the killer t oxin increased with the presence of NaCl in the medium used for testing the killing action. Production of the killer toxin was stimulated in the prese nce of proteins of complex culture media. Addition of nonionic detergents a nd other additives, such as dimethylsulfoxide enhanced killer toxin product ion significantly. Killer toxin secretion pattern followed the growth curve and reached its maximum activity at the early stationary phase. Optimal st ability was observed at pH 4.5 and temperatures up to 20 degreesC. Above pH 4.5 a steep decrease of the stability was noted. The activity was hardly d etectable at pH 5.1.