Abstract #T49

# T49
Growth and short-chain fatty acid production by potential probiotic lactobacilli.
J. Renye*1, A. Hotchkiss1, A. White1, 1Dairy and Functional Foods Research Unit, ERRC, ARS, USDA, Wyndmoor, PA.

Prebiotics are nondigestible food ingredients selectively used by beneficial bacteria within the colon to improve host health. Inulin and fructo-oligosaccharides (FOS) are well-studied prebiotics that can be metabolized by strains of lactobacilli and bifidobacteria; and are associated with improved digestive health in humans due to the production of short-chain fatty acids (SCFA). Prebiotics have also been shown to improve the growth, survival and bioactivities of probiotics, which has led to the development of synbiotics, where pre- and probiotics are delivered together to optimize their beneficial activities. In this study, we screened 87 strains of lactobacilli for their ability to grow with inulin (Synergy 1) or FOS (P95) provided as the sole source of fermentable carbohydrates. Growth in modified MRS broth (no glucose) containing 1% inulin or FOS (m/v) was monitored for 24h in a Cytation 5 multi-mode plate reader (BioTeck). Nine lactobacillus strains fermented both prebiotics, reaching an optical density (OD600) ≥ 1.2, including L. casei (strains: LC3, 441 and ATCC 4646); L. helveticus (strains: 1842 and 1929); L. lactis FARR; L. paracasei ssp. paracasei 4564; L. acidophilus 1426; and L. reuteri 1428. Bifidobacterium breve 2141 was also screened and fermented both prebiotics reaching an OD >1.6. High-performance liquid chromatography was used to identify SCFAs in cell free supernatants (CFS) from 20 cultures that reached an OD ≥0.5. For the 9 lactobacillus strains above, the concentration of lactic acid was between 175 and 206 mM, and L. helveticus 1929 produced the highest concentration of acetic acid (~19 mM). In the presence of FOS, the highest concentrations of propionic (3.9–6.2 mM) and butyric acids (0.9–1.2 mM) were detected in CFS from L. reuteri 1428, L. paracasei ssp. paracasei 4564 and L. plantarum 23115. With inulin, L. acidophilus 1426 and L. delbrueckii ssp. lactis 735 produced the highest concentrations of propionic acid (4.2 mM); and L. acidophilus 1426, L. paracasei ssp. paracasei 4564 and L. plantarum 23115 produced the most butyric acid (1.0 mM). Results from this study are essential to identify lactobacillus strains suitable for the development of synbiotics utilizing FOS or inulin as prebiotics components.

Key Words: prebiotic, Lactobacillus, probiotic