Abstract:

In order to expand the application of lactic acid bacterial biofilm in the food industry and construct edible
functional carrier, amino acids which could be used as ligands for bacterial adhesion were modified onto alginate in this
study. The structures, compositions, electrical properties and hydrophilicity of the modified carriers (Alg-Arg and Alg-Lys)
were characterized by nuclear magnetic resonance, amino acid content analysis, and ζ potential and water contact angle
measurement. Lactobacillus kefiranofaciens ZW3 was cultured on the carriers to investigate its growth and extracellular
exopolysaccharide secretion. The results showed that after cultivation for 4 d, the amount of ZW3 on Alg-Arg reached up to
3.8 × 107 CFU/cm2, which was 3.5 times as high as that on Alg-Lys. The secretion amount of extracellular exopolysaccharide
was 28.2 μg/cm2, which was increased by 2.4 times in comparison with that on Alg-Lys. Compared with lysine-modified
carrier, arginine-modified carrier was better for ZW3 growth and the secretion of extracellular exopolysaccharide. These
results demonstrated that biofilm formation could be enhanced by the appropriate ligand.

Key words: amino acid, sodium alginate, biofilm, Lactobacillus, ligand