The predominance of Lactobacillus sanfranciscensis in French organic sourdoughs and its impact on related bread characteristics

• Published in: International journal of food microbiology 2015-11, Vol.213, p.40-48
• Main Authors: Lhomme, Emilie, Orain, Servane, Courcoux, Philippe, Onno, Bernard, Dousset, Xavier
• Format: Article
• Language: English
• Subjects: 454 pyrosequencing; Base Sequence; Biodiversity; Bread - microbiology; Candida - genetics; Candida - isolation & purification; DNA, Bacterial - genetics; DNA, Ribosomal - genetics; Fermentation; France; Lactic acid bacteria; Lactobacillus - genetics; Lactobacillus - isolation & purification; Life Sciences; Real-time PCR; Real-Time Polymerase Chain Reaction; RNA, Ribosomal, 16S - genetics; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - isolation & purification; Sequence Analysis, DNA; Sourdough
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2015.05.010

Fourteen bakeries located in different regions of France were selected. These bakers use natural sourdough and organic ingredients. Consequently, different organic sourdoughs used for the manufacture of French bread were studied by the enumeration of lactic acid bacteria (LAB) and 16S rRNA sequencing of the isolates. In addition, after DNA extraction the bacterial diversity was assessed by pyrosequencing of the 16S rDNA V1–V3 region. Although LAB counts showed significant variations (7.6–9.5log10CFU/g) depending on the sourdough studied, their identification through a polyphasic approach revealed a large predominance of Lactobacillus sanfranciscensis in all samples. In ten sourdoughs, both culture and independent methods identified L. sanfranciscensis as the dominant LAB species identified. In the remaining sourdoughs, culture methods identified 30–80% of the LAB as L. sanfranciscensis whereas more than 95% of the reads obtained by pyrosequencing belonged to L. sanfranciscensis. Other sub-dominant species, such as Lactobacillus curvatus, Lactobacillus hammesii, Lactobacillus paralimentarius, Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus sakei, were also identified. Quantification of L. sanfranciscensis by real-time PCR confirmed the predominance of this species ranging from 8.24 to 10.38log10CFU/g. Regarding the acidification characteristics, sourdough and related bread physico-chemical characteristics varied, questioning the involvement of sub-dominant species or L. sanfranciscensis intra-species diversity and/or the role of the baker's practices. •Lactobacillus sanfranciscensis was highly predominant in French organic sourdoughs.•Sub-dominant bacterial species varied depending on the sourdoughs.•Pyrosequencing, real-time PCR, and cultural methods complemented microbiota description.