RHEOLOGICAL CHARACTERISTICS AND FUNCTIONS OF EXOPOLYSACCHARIDES OF AZOTOBACTER-BEIJERINCKII AND MYCOBACTERIUM-LACTICOLUM

Exopolysaccharides of Azotobacter beijerinckii and Mycobacterium lacti colum produce highly viscous solutions. Their viscosity decreases both at the increase of concentrations of mono- or bivalent metal salts an d at the alteration of pH in the native solutions of polymers in disti lled water. Depyruvilation of A. beijerinckii polysaccharide sharply d ecreases viscosity of its solution. Deacetylation of the polysaccharid e results in a decrease of its solubility in the presence of salts of bivalent metals. Capsules of A. beijerinckii and M. lacticolum promote bacterial adhesion to hydrophilic surfaces (glass). Decapsulation of the bacterial cells increases their hydrophobicity and decreases capab ility of eels for adhesion. The presence of free extracellular polysac charides increases resistance of the bacteria to high concentrations o f copper ions.