The synergistic effects of Lactobacillus casei HDS-01-konjac glucomannan synbiotic: probiotic potential and in vitro fecal fermentation.

KGM selectively stimulated the growth of L. casei HDS-01, confirming a synergistic effect between the probiotic and prebiotic components.

• L. casei HDS-01 was selected as the probiotic component due to its mannanase-producing capability
• KGM was derived from konjac powder
• The selective stimulation of growth confirmed the synergistic rather than merely additive relationship between components
• This synergism was the basis for classifying the combination as a synergistic synbiotic

L. casei HDS-01 demonstrated tolerance to gastrointestinal conditions including low pH, bile salts, and NaCl concentrations.

• Survival rate exceeded 55% at pH levels of 2.5–5.5
• Survival rate exceeded 55% at bile salt concentrations of 0–0.35 g/L
• Survival rate exceeded 55% at NaCl concentrations of 1–8 g/L
• These results suggest L. casei HDS-01 can survive in the gastrointestinal tract

KGM significantly enhanced the intestinal colonization ability of L. casei HDS-01.

• The colonisation ability of L. casei HDS-01 in the intestinal tract was significantly enhanced by KGM
• This finding supports the functional role of KGM as a prebiotic that facilitates probiotic establishment in the gut
• The enhancement of colonization is considered a key mechanism of the synbiotic effect

Konjac oligo-glucomannan (KOGM) showed superior antidigestive properties in gastric juice compared to inulin.

• 94% of KOGM was expected to reach the jejunum of the small intestine after entering the human digestive system
• The antidigestive property of KOGM in gastric juice was better than that of inulin
• This high resistance to digestion supports KOGM's function as an effective prebiotic substrate reaching the colon

The L. casei HDS-01-KGM synbiotic promoted the highest proliferation of gut SCFAs-producing bacteria during in vitro fecal fermentation compared to other treatment groups.

• The synbiotic group achieved 2.43 × 10⁸ CFU/mL of SCFAs-producing bacteria
• This bacterial count was higher than those of other treatment groups
• In vitro fecal fermentation methodology was used to assess these outcomes

The L. casei HDS-01-KGM synbiotic produced the highest concentrations of acetic acid, propionic acid, and butyric acid compared to other treatment groups.

• Acetic acid content was 7.68 ± 0.04 μg/mL
• Propionic acid content was 6.72 ± 0.03 μg/mL
• Butyric acid content was 4.37 ± 0.06 μg/mL
• All three SCFA concentrations were higher than those of the other treatment groups

The L. casei HDS-01-KGM synbiotic modulated gut microbiota composition by enhancing beneficial bacteria and reducing harmful bacteria.

• The synbiotic enhanced the population of beneficial bacteria such as Pediococcus
• The synbiotic significantly reduced harmful bacteria such as Shigella
• These microbiota changes were observed in in vitro fecal fermentation experiments