Exopolymeric production by bacterial strains isolated from activated sludge of paper industry

The bacteria originated from the paper mill sludge were identified, isolated and cultured. Enterobacter (E) and Klebsiella (K) represented 70% of the culturable aerobic flora. Kinetics of EPS production in isolated culture and in arbitrary 1:1 mixture was investigated by high-pressure size exclusion chromatography (HPSEC). In isolated culture, Enterobacter produced regularly and gradually during 24 h of culture, while Klebsiella produced the total amount of EPS already after 4 h without any changes later. The chromatographic profiles of the EPS production of the 1:1 mixture after 4, 8 and 24 h of culture could be fitted as a linear combination of the profiles of exopolymers produced by pure Enterobacter and Klebsiella strains. After 24 h of culture, Enterobacter was predominant in term of population (82%) and produced about 77% EPS amount, in spite of competition phenomena observed during culture.