An alternative method for screening lactic acid bacteria for the production of exopolysaccharides with rapid confirmation
Elinalva Maciel Paulo, Murilo Pinho Vasconcelos, Ivelise Santiago Oliveira, Helen Michelle de Jesus Affe, Rosely Nascimento, I. S. de Melo +2 more
Food Science and Technology
Abstract
The accumulation of exopolysaccharides (EPS) produced by microorganisms occurs in the presence of excess substrate and limiting conditions of elements that are essential to growth, such as nitrogen, phosphorus, sulfur, and magnesium. The presence of EPS produced by bacterial cells contributes to slime colonies formation in solid medium and increased viscosity in liquid medium. This paper proposes an alternative method for screening EPS-producing lactic acid bacteria using solid medium-containing discs of filter paper that are saturated with active cultures. The screening was carried out under different culture conditions varying the type of sugar, pH, and temperature. EPS production was visualized by the presence of mucoid colonies on the discs, which was confirmed by the formation of a precipitate when part of this colony was mixed with absolute alcohol. The established conditions for obtaining a high number of isolates producing EPS were 10% sucrose, pH 7.5 and 28 ºC. This method proved to be effective and economical because several strains could be tested on the same plate, with immediate confirmation.
Extracted Claims
5 claims extracted from this paper into the knowledge graph
exopolysaccharides (EPS) production occurs in the presence of excess substrate and limiting conditions of elements that are essential to growth
“The accumulation of exopolysaccharides (EPS) produced by microorganisms occurs in the presence of excess substrate and limiting conditions of elements that are essential to growth, such as nitrogen, p...”
EPS production contributes to slime colonies formation in solid medium and increased viscosity in liquid medium
“The presence of EPS produced by bacterial cells contributes to slime colonies formation in solid medium and increased viscosity in liquid medium.”
EPS production was confirmed by the formation of a precipitate when part of this colony was mixed with absolute alcohol
“EPS production was visualized by the presence of mucoid colonies on the discs, which was confirmed by the formation of a precipitate when part of this colony was mixed with absolute alcohol.”