FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Biosynthesis of exopolysaccharides and their role in the adhesion of Bacillus megaterium to a stainless steel surface


The purpose of this investigation was to determine the effect of availability of nutritious components in a culture medium on the biosynthesis of exopolysaccharides (EPS) Bacillus megaterium. Furthermore, a dependence between the amount of EPS produced and the adhesion of bacteria to stainless steel surface (304L) was defined. For the purpose of determining the amount of EPS synthesized, they were separated by ultrasonic waves and, after the acid hydrolysis accomplished, a spectrophotometric assay was applied. The adhesion of Bacillus megaterium was investigated by an absolutely novel method of estimating degrees of adhesion on a nine-degree scale; so far, this method has not been mentioned in any literature. It was proved that in the majority of experimental cases, the highest level of the EPS biosynthesis occurred at the beginning of this process (during the 4th and 8th hour). When the source of nitrogen was unavailable during the initial 24 hours of the process, no extracellular carbohydrates were present. An intensified production of carbohydrates was reported only during the 48th hour of the process ensuing, with a very high production level (0,035 mg EPS/ 10cfu). In the majority of experimental cases, it was proved that a correlation existed between the amount of synthesized exopolysaccharides, at each individual stage of development of the bacterial culture, and the adhesion of Bacillus megaterium cells to a stainless steel surface. Additionally, it was reported that the adhesion degree of bacteria was higher during a low production of extracellular polysaccharides. Tis fact shows that, besides the biosynthesis of exopolysacchariodes, some other factors play a significant role in the adhesion of micro-organisms to abiotic surfaces.


exopolysaccharides (EPS), biofilm, adhesion