Short communication: Lactose enhances bile tolerance of yogurt culture bacteria

Abstract

Lactose is an energy source for culture bacteria. Bile tolerance is an important probiotic property. Our aim was to elucidate the effect of lactose on bile tolerance of yogurt starter culture Lactobacillus bulgaricus LB-12 and Streptococcus thermophilus ST-M5. Bile tolerance of pure cultures was determined using 0.3% oxgall in MRS THIO broth (Difco, Becton Dickinson, Sparks, MD) for L. bulgaricus and 0.3% oxgall in M17 broth (Oxoid, Basingstoke, UK) for Strep. thermophilus. Lactose was added to both broths at 0 (control), 1, 3, and 5% (wt/vol) broth. Dilutions were plated hourly for 12 h. Experiments were replicated 3 times. At 2, 4, and 12 h of incubation, lactose incorporated at all amounts, 1, 3, and 5% (wt/vol), showed higher counts of Strep. thermophilus ST-M5 compared with the control. Lactose use at 5% (wt/vol) significantly enhanced bile tolerance of both L. bulgaricus and Strep. thermophilus compared with control.

Effect of Flaxseed on Bile Tolerances of <i>Lactobacillus acidophilus, Lactobacillus bulgaricus</i>, and <i>Streptococcus thermophilus</i>

“…Addition of up to 3% whey protein isolate improved the bile tolerance of pure cultures of S. thermophilus ST-M5 and L. bulgaricus LB-12 during 5 h of oxgall exposure [31]. Likewise, addition of 5% lactose improved the bile tolerance of pure cultures of S. thermophilus ST-M5 and L. bulgaricus LB-12 during 12 h of oxgall exposure [32]. Addition of inulin to yogurt milk improved the ability of L. acidophilus to tolerate bile salts compared to L. acidophilus in yogurt not containing inulin [33].…”

Assessment of the safety and probiotic properties of Roseburia intestinalis: A potential “Next Generation Probiotic”

“… Gou et al (2021) used soybean lecithin and whey protein concentrate to treat Lacticaseibacillus paracasei and successfully increased its tolerance to bile salts and acids. Evidence suggests that 5% lactose can enhance the bile salt tolerance of L. bulgaricus ( Mena and Aryana, 2018 ), whereas soy lecithin ( Hu et al, 2015 ) can enhance the bile salt resistance of L. plantarum and whey protein ( Vargas et al, 2015 ) can enhance the acid and bile salt tolerance of Streptococcus thermophilus . Biofilm formation by probiotics can inhibit pathogens from colonizing the mucosa ( Deng et al, 2020 ).…”

“…The pH values of the duodenum, terminal ileum, cecum, and rectum are 6.0, 7.4, 5.7, and 6.7, respectively (Fallingborg, 1999). Several methods have been reported for enhancing the tolerance of probiotics to bile Evidence suggests that 5% lactose can enhance the bile salt tolerance of L. bulgaricus (Mena and Aryana, 2018), whereas soy lecithin (Hu et al, 2015) can enhance the bile salt resistance of L. plantarum and whey protein (Vargas et al, 2015) can enhance the acid and bile salt tolerance of Streptococcus thermophilus. Biofilm formation by probiotics can inhibit pathogens from colonizing the mucosa (Deng et al, 2020).…”

Application of the Combination of Soybean Lecithin and Whey Protein Concentrate 80 to Improve the Bile Salt and Acid Tolerance of Probiotics

“…Therefore, we investigated the bile salt tolerance of L. paracasei L9 and determined that it is a bile salt-sensitive strain. Generally, strategies to improve the bile salt tolerance of probiotics include isolation and screening from the natural environment [ 26 ], addition of exogenous substances [ 9 - 11 ], mutation breeding, acclimatization [ 23 ], gene modification by genetic engineering, metabolism engineering [ 27 , 28 ], and microencapsulation technologies [ 29 , 30 ]. However, it is difficult to isolate and screen probiotic strains with both health benefits and bile salt tolerance in nature.…”

“…In recent years, many researchers have investigated the effects and mechanisms of various substances on bile salt resistance. Specifically, treatment of probiotics with exogenous substances, such as lactose [ 9 ], soy lecithin [ 10 ], whey protein isolates [ 11 ], maltodextrin [ 12 ], and lotus seed resistant starch [ 13 ], can effectively enhance bile salt tolerance by enhancing cell hydrophobicity, altering the fatty acid composition of the cell membranes, and inducing the expression of bile salt hydrolase genes. However, the initial survival rate of probiotics cannot be recovered after treatment with these substances, and different effects are observed in different species.…”