Identification of Lactobacillus Strains Capable of Fermenting Fructo-Oligosaccharides and Inulin

Abstract

Novel probiotic strains that can ferment prebiotics are important for functional foods. The utilization of prebiotics is strain specific, so we screened 86 Lactobacillus strains and compared them to Bifidobacterium breve 2141 for the ability to grow and produce SCFA when 1% inulin or fructo-oligosaccharides (FOS) were provided as the carbon source in batch fermentations. When grown anaerobically at 32 °C, ten Lactobacillus strains grew on both prebiotic substrates (OD600 ≥ 1.2); while Lactobacillus coryniformis subsp. torquens B4390 grew only in the presence of inulin. When the growth temperature was increased to 37 °C to simulate the human body temperature, four of these strains were no longer able to grow on either prebiotic. Additionally, L. casei strains 4646 and B441, and L. helveticus strains B1842 and B1929 did not require anaerobic conditions for growth on both prebiotics. Short-chain fatty acid analysis was performed on cell-free supernatants. The concentration of lactic acid produced by the ten Lactobacillus strains in the presence of prebiotics ranged from 73–205 mM. L. helveticus B1929 produced the highest concentration of acetic acid ~19 mM, while L. paraplantarum B23115 and L. paracasei ssp. paracasei B4564 produced the highest concentrations of propionic (1.8–4.0 mM) and butyric (0.9 and 1.1 mM) acids from prebiotic fermentation. L. mali B4563, L. paraplantarum B23115 and L. paracasei ssp. paracasei B4564 were identified as butyrate producers for the first time. These strains hold potential as synbiotics with FOS or inulin in the development of functional foods, including infant formula.

Cranberry Arabino-Xyloglucan and Pectic Oligosaccharides Induce Lactobacillus Growth and Short-Chain Fatty Acid Production

“…Acetate production by both bifidobacteria and lactobacilli has been reported under anaerobic and glucose limiting conditions [42,43], but the level of lactate production observed in our study suggested that the bacteria may not have been stressed under the current growth conditions when compared to other studies. Lactate being the primary organic acid produced also agreed with previous results from our laboratory when lactobacilli and bifidobacteria were grown in the presence of FOS and inulin as a sole carbon source [41].…”

“…Short chain fatty acid production was monitored for the 11 Lactobacillus strains and Bifidobacterium breve 2141, which showed optimal growth on cranberry A6 ( Figure 5 ). All strains were shown to produce predominantly lactic acid (>70 mM), which agreed with previous results from our laboratory using FOS and inulin as the sole carbon source [ 41 ], but disagreed with a previous study that reported lactate production was <10 mM for L. plantarum ATCC BAA 793 and B. longum subsp. longum UD401 when grown on cranberry xyloglucans [ 30 ].…”

“…The higher culture density observed in this study could have resulted from compositional differences between the cranberry A6 preparations used, or differing growth conditions which include the use of oxyrase to induce an anaerobic environment, and a lower incubation temperature of 32 °C. A previous study from our laboratory showed that some Lactobacillus strains utilized FOS or inulin better when grown at 32 °C instead of 37 °C, including strains L. casei 4646, L. paracasei B4564 and to a lesser extent L. reuteri 1428 which were identified as growing on cranberry A6 in this study [ 41 ]. Additionally, L. rhamnosus GG was reported to not utilize cranberry A6 in both the current study and the Ozcan et.…”

“…Taken together, these results confirm that careful consideration needs to be given to the Lactobacillus strain, choice of prebiotic and environmental conditions when assessing oligosaccharide utilization, potentially for the development of a novel synbiotic. well on both substrates (OD600 > 1.0) [41]. When compared with the results from this study, three strains were identified as being able to utilize all three substrates: L. casei 4646, L. paraplantarum B23115 and L. reuteri 1428.…”

“…Results from this study demonstrated that cranberry A6 utilization was strain-dependent, as several other strains of Lactobacillus species were unable to reach a final OD 600 = 0.40, including: two L. buchneri (B1838, B1860), seven L. bulgaricus (LB1, LB6, LB12, LB15, LB21, YB1, B440), five L. casei (LC2, 393, B1922, B441, LC3), five L. delbrueckii (B443, B736, B1844, B1930, B4523), two L. fermentum (B585, B14171), five L. plantarum (14917, NCDO955, B1846, B1926, TSH076), and two L. rhamnosus (LGG, B1914) strains. A previous study in our laboratory looked at the growth of this panel of lactobacilli using commercial FOS and inulin as sole carbon sources and identified 12 which grew equally well on both substrates (OD 600 > 1.0) [ 41 ]. When compared with the results from this study, three strains were identified as being able to utilize all three substrates: L. casei 4646, L. paraplantarum B23115 and L. reuteri 1428.…”