Isolation and identification of exopolysaccharide producer lactic acid bacteria from Turkish yogurt

Abstract

Lactic acid bacteria (LAB) were isolated from traditional yogurt samples and genotypic characterization of these isolates revealed the presence of 21 distinct LAB strains belonging to Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Leuconostoc mesenteroides, and Lactobacillus plantarum as new LAB strains. Determination of the exopolysaccharide (EPS) production characteristics of the selected strains of each species revealed that all strains possessed at least one gene required for both homopolymeric-and heteropolymeric-type EPS production. Structural analysis of the EPSs showed that L. delbrueckii subsp. bulgaricus Y39 and S. thermophilus Y102 produced heteropolymeric EPS containing glucose and galactose, whereas Leuc. mesenteroides Y35 and L. plantarum Y36 produced homopolymeric glucan-type EPS. The level of EPS production in these strains was found to be in a similar range. These strains with EPS production characteristics are good candidates for future studies as new LAB for yogurt production. Practical applicationsRecent trends in yogurt production technology have led to an increased use of ropy starter cultures in yogurt production due to the technological roles of exopolysacharides (EPS) produced by these cultures. The main role of EPS in yogurt production is to improve the textural properties of yogurt as an in situ produced natural polymer. In addition to the yogurt starter cultures, use of adjunct cultures during production of yogurt is also of special interest to enhance the technological and nutritional characteristics of yogurt. Therefore, in this study, potential yogurt starter and adjunct cultures from traditional yogurt samples with EPS production characteristics were isolated.From these isolates, Lactobacillus delbrueckii subsp. bulgaricus Y39 and Streptococcus thermophilus Y102 produced heteropolymeric EPS containing glucose and galactose, whereas Leuconostoc mesenteroides Y35 and Lactobacillus plantarum Y36 produced homopolymeric glucan.

Optimization of exopolysaccharide production of Lactobacillus brevis E25 using RSM and characterization

“…Lb. brevis E25 was shown to produce a homopolymeric glucan type EPS consisting only glucose in its repeating unit [8] which agrees with the data reported previously [18] [3], [4]. In contrast some researchers report that some strains may produce heteropolymeric EPS with glucose and galactose in its repeating unit structure.…”

Effect of Probiotic Lactic Acid Bacteria (LAB) on the Quality and Safety of Greek Yogurt

“…L. plantarum strains can produce exopolysaccharide (EPS), a macromolecule composed of monosaccharide residues of sugar and sugar derivatives. EPS can act as an important factor in the physicochemical and rheological properties of yogurt due to its role as a natural concentrate agent and stabilizer [ 34 , 35 ]. Nambiar et al [ 36 ] have reported that EPS isolated from L. plantarum HM47 has high thermal stability and that it can enhance the texture of yogurt at a low pH (4.0).…”

Prevention of Sourdough Bread Mould Spoliage by antifungal Lactic Acid Bacteria Fermentation

“…The column temperature was kept constant at 25°C and deionized water was used as mobile phase. Sugars such as glucose, sucrose, fructose, xylose, arabinose were used to create the standard calibration curve (Ispirli and Dertli, 2018).…”