Exopolysaccharides from lactic acid bacteria: biodiversity and technological potential

FERNANDA MOZZI; CECILIA RODRÍGUEZ; ROEL VAN DER MEULEN; RAÚL RAYA; LUC DE VUYST; GRACIELA FONT DE VALDEZ

Tucumán, Argentina

Simposio; II Simposio Internacional de Bacterias Lácticas. Primer Encuentro Red BAL Argentina.; 2006

CERELA

Certain lactic acid bacteria (LAB) produce exopolysaccharides (EPS), which can be synthesized as capsular polysaccharide (CPS), loosely attached to the cell surface, or as slime EPS, secreted into the environment. These biopolymers can be either homopolysaccharides (composed of one type of monosaccharide) or heteropolysaccharides (HePS, made of repeating units containing two or more different monosaccharides). A broad biodiversity of HePS from LAB exists concerning the type of EPS produced (CPS/slime), their monomer composition, molecular mass, glycosidic unions and yields; these characteristics being determinant for their functionality. The EPS biodiversity might be related to the diverse sugar nucleotides biosynthetic routes and the genetic potential of the strains. EPS from LAB have found industrial application due to their interesting rheological properties and the food-grade status of the producing strains. LAB strains are widely used in the fermented food industry and their in situ EPS production has been employed in the elaboration of dairy products mainly fermented milks (stirred and drinking yogurts) and more recently in the manufacture of low fat cheeses (Mozzarella and Cheddar type). Moreover, it has been claimed that these biopolymers have potential health benefits and play a role in certain biological functions such as protecting the cells against adverse environmental conditions. Recently, it has been suggested that CPS formation by Streptococcus thermophilus strains could protect the cells from phage attack. Exploiting the biodiversity of HePS from LAB and of the polymer-producing strains could open up the possibility to achieve new/desired functionalities.