[Gram-negative bacteria contaminating the process of producing lysine].

The authors have isolated Gram-negative bacteria of the Enterobacteriaceae family from the culture liquid of industrial fermenters with low yield of lysine. Most of them possessed the characters typical of Klebsiella pneumoniae and Escherichia coli, the rest were identified as the representatives of genera Proteus, Providencia, Enterobacter, Hafnia. Strains of Klebsiella pneumoniae, E.coli, Proteus rettgeri manifested lysine-decarboxylase activity. The capacity of some strains to destruct lysine synthesized by the target culture in the process of fermentation with formation of cadaverin was experimentally proved and confirmed under production conditions. Technological water is the source of distribution of gram-negative bacteria (first of all Klebsiella) in lysine production.