Characterisation of an Exopolysaccharide Preventing Phage Adsorption in Lactococcus lactis subsp. cremoris MA39


Abstract: Lactococcus lactis subsp. cremoris strain MA39 produces an extracellular polysaccharide containing rhamnose, glucose and galactose. A 16.5 kb plasmid encoding exopolysaccharide production in MA39 was determined by plasmid curing experiments. Phage adsorption assays showed that four different lactococcal phages were adsorbed to MA39-40; only the 16.5 kb plasmid cured an exopolysaccharide non-producing mutant of strain MA39, with high efficiency (93.2-98.5%) while adsorption of these phages was completely inhibited in the wild type strain MA39. These results suggest that exopolysaccharide prevents phage adsorption by masking phage receptor sites.

Keywords: Exopolycaccharide, phage resistance, Lactococcus lactis subsp. Cremoris

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