Impact of glycomacropeptide on growth, adhesion, and biofilm formation of the probiotic <i>Lacticaseibacillus rhamnosus</i> GG

Glycomacropeptide (GMP) is a milk-derived bioactive peptide with demonstrated prebiotic properties. It is composed of a 64-amino acid framework and different carbohydrate molecules, which may serve as carbon sources for beneficial bacteria. <i>Lacticaseibacillus rhamnosus</i> GG (LGG) is a widely used probiotic strain that promotes intestinal barrier function, prevents pathogen colonisation and exerts anti-inflammatory and immunomodulatory activities. In this study, we explored the effect of GMP supplementation to LGG cultures on growth, adhesion and biofilm-forming properties of the bacterium. Prebiotic GMP promoted LGG growth and acidifying activities, mainly under anaerobiosis, without modifying the binding-mucus ability. GMP supplementation also increased LGG-biofilm biomass 3.8- and 3.4-fold under aerobic and anaerobic conditions. Besides, GMP treatment increased LGG-biofilm volume 4.7-fold, thickness by 39% and roughness by 110%. Thus, incorporating GMP into food or nutraceutical formulations might represent a viable strategy to enhance the probiotic efficacy of LGG strain, potentially improving its performance in functional products.