title: Lactic acid bacterium and yeast microbiotas of sixteen French traditional sourdoughs.
abstract: Sixteen sourdoughs (FS1-FS16) used for the manufacture of traditional French breads were characterized by strongly acid conditions (median value of pH 3.5). The concentration of free amino acids (FAA) was highly variable, due to different proteolytic activity of flour used for back slopping and of dominant microorganisms. Median value of cell density of lactic acid bacteria (LAB) was 9.2 log CFU/g. The ratio between LAB and yeasts ranged from 10,000:1 to 10:1. According to the culture-dependent method and 16S metagenetics, Lactobacillus sanfranciscensis was the dominant species in French sourdoughs. FS5 and FS15, propagated according to protocols including one back slopping step at 14 °C, were the only exceptions. High positive correlations were found between L. sanfranciscensis, temperature of back slopping and FAA. The results of this study highlighted the broad adaptability of L. sanfranciscensis to very acid sourdough. Besides species frequently encountered (e.g., Lactobacillus parabrevis/Lactobacillus hammesii, Lactobacillus plantarum and Leuconostoc mesenteroides), first Lactobacillus xiangfangensis (FS5) and Lactobacillus diolivorans (FS15) were found in sourdough. As determined by RAPD-PCR analyses, the sourdough samples showed a different number of strains, ranging from 5 (FS9, FS11 and FS15) to 12 (FS1 and FS13), meaning a highly variable bacterial diversity. Cluster analysis showed that different sourdoughs, especially when propagated in the same bakery, may harbor similar strains. Except for L. plantarum (FS5) and Ln. mesenteroides (FS3), all the dominant species were detected by both 16S metagenetics and culture-dependent method. Yeast diversity was lower than LAB. Except for FS4 (solely dominated by Kazachstania servazzii), yeast microbiota of French sourdoughs was dominated by Saccharomyces cerevisiae. Strains isolated in this study could be a useful base for developing new basic researches on physiology, metabolism, and intraspecific diversity of L. sanfranciscensis, as well as for standardizing the quality of traditional French breads.
authors.affiliation: LUNAM Université Oniris, Laboratoire de Microbiologie Alimentaire et Industrielle, Nantes Cedex 3, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Lhomme
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Lattanzi
authors.affiliation: LUNAM Université Oniris, Laboratoire de Microbiologie Alimentaire et Industrielle, Nantes Cedex 3, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Dousset
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy. Electronic address: fabio.minervini@uniba.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Minervini
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: De Angelis
authors.affiliation: Puratos Group, Bakery Flavour & Yeast, Industrialaan, 25, 1702 Groot-Bijgaarden, Belgium.
authors.forename: Guylaine
authors.initials: G
authors.lastname: Lacaze
authors.affiliation: LUNAM Université Oniris, Laboratoire de Microbiologie Alimentaire et Industrielle, Nantes Cedex 3, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Onno
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Gobbetti
mesh_terms: D001939:Bread / Q000382:microbiology*; D005285:Fermentation; D005433:Flour / Q000382:microbiology*; D005516:Food Microbiology; D019344:Lactic Acid / Q000378:metabolism; D007778:Lactobacillus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D007934:Leuconostoc / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D064307:Microbiota; D019105:Random Amplified Polymorphic DNA Technique; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D013696:Temperature; D015003:Yeasts / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D019344:Lactic Acid
keywords: Lactic acid bacteria; Lactobacillus sanfranciscensis; Sourdough