THE ROLE OF RESISTANCE TO BILE SALTS AND ACID TOLERANCE OF EXOPOLYSACCHARIDES (EPSS) PRODUCED BY YOGURT STARTER BACTERIA


Boke H., ASLIM B. , Alp G.

ARCHIVES OF BIOLOGICAL SCIENCES, vol.62, no.2, pp.323-328, 2010 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 62 Issue: 2
  • Publication Date: 2010
  • Doi Number: 10.2298/abs1002323b
  • Title of Journal : ARCHIVES OF BIOLOGICAL SCIENCES
  • Page Numbers: pp.323-328

Abstract

The aim of this study was to investigate a possible relation between EPS production and resistance to bile salts and tolerance to low pH. Eight strains which produced the highest and lowest amount of EPS (16- 211mg/l) were selected among 54 bacteria isolated from yogurt. Additionally, they were tested for resistance to bile salts (0.15, 0.3 %) and tolerance to low pH (2.0-3.0). After treatment with bile salts and acid, viable bacteria (log cfu ml-1) were determined by surface plating. The high EPS producing strains (B3, G12, W22) showed a significant (P<0.05) protective effect against low pH (pH 2.0). All Streptococcus thermophilus strains showed a higher tolerance to bile salts than the Lactobacillus delbrueckii subsp. bulgaricus strains. The high EPS-producing S. thermophilus (W22, T12) and L. bulgaricus (B3, G2) strains showed a significant (P<0.01) protective effect against bile salts (0.3 %).