International Journal of Dairy Science and Technology ISSN: 1716-3498 Vol. 3 (1), pp. 165-171 March, 2017. © Advanced Scholars Journals

Full Length research Paper

Phage infection of capsule-producing lactic acid bacteria with ultimate application in the formulation of phage-inhibitory

*Abraham D. Presley, Donald Ali Monroe and Albert Hemingway

Department of Food Science and Technology, University of Georgia, Athens, GA 30602 USA.

*Corresponding author. E-mail: [email protected] 

Accepted 16 January, 2017

Abstract

Lactic cultures that produce capsular polysaccharides are widely used in the dairy industry. However, little information is available on their phage-cell interactions. Concanavalin A (Con A), lysozyme, and saccharides were investigated for their ability to modify phage-cell interactions in such a manner as to inhibit phage infection. The ability of phage to infect cells was determined by measuring acid production in Elliker broth. Acid production by capsule-producing Streptococcus thermophilus was inhibited less by bacteriophage when cells were pretreated with Con. A than was acid production by a capsule-free variant. The presence of 0.5 mg/ml lysozyme in Elliker broth significantly reduced phage infection. However, there was no increased effect when lysozyme and Con A were combined in the growth medium. The addition of 5 g/L of glucosamine to Elliker broth also inhibited phage infection. The results of this study indicate that it is possible to reduce phage infection of capsule-forming S. thermophilus by blocking or modifying phage adsorption sites.

Key words: Capsular polysaccharides, Concanavalin A, bacteriophage adsorption, adsorption sites, phage inhibition.