Screening for β-D-glucan producing lactic acid bacteria isolated from environmental sources

; ; ; ; ; (). Screening for β-D-glucan producing lactic acid bacteria isolated from environmental sources: Poster. In: VIth Sourdough and Cereal Fermentation Symposium. ( 30.9.-2.10.2015). Nantes: Oniris and INRA.

Some lactic acid bacteria (LAB) are well known for the production of exopolysaccharides (EPS), i.e. homopolysaccharides and heteropolysaccharides. The class of β-glucans comprises a specific group of homopolysaccharides with various positive physiochemical and health promoting aspects. So far, β-glucan production was mainly described in cider spoilage LAB, including Pediococcus parvulus, Oenococcus oeni, and Lactobacillus diolivorans, that were responsible for an undesired alteration of the fermented beverages related to ropiness (1, 2, 3). In contrast to these undesired effects, β-glucan producing LAB incorporated in sourdough may act beneficially on bread quality with benefits in texture and constitutional properties. In this study, we focused on β-glucan production in beneficial LAB isolated from environmental sources with the aim to improve the quality of bakery products by functional microbial metabolites. We therefore selected 83 strains of LAB that were previously isolated from sourdough, fresh baker’s yeast, raw milk, raw and fermented meat, and silage followed by MALDI-TOF MS identification. The screening for β-glucan production was done by a 2-phased strategy described by Werning et al. (2), i.e. an agglutination assay with Streptococcus pneumoniae type 37-specific antisera followed by PCR amplification of a 417-bp fragment of the glycosyltransferase (gtf) gene encoding a β-D-glucan synthase. In doing so, a total of 8 strains belonging to the species Lactobacillus plantarum (3 strains), L. brevis (2 strains), L. paracasei (1 strain), L. mali (1 strain), and Leuconostoc mesenteroides (1 strain) were successfully identified as genotypic β-glucan producers. These strains seem to be very interesting for further application in sourdoughs. First tests including optimization of β-glucan production are currently under investigation.