Effect of Leavening Time in Sourdough Microbiota: An Approach Using Organic and Conventional Whole Wheat Flours

Abstract

Until today, little is known about the effect of leavening time in the bacterial and fungal diversity and stability in sourdough. The aim of this study was to use a metagenomic analysis to assess microbial population at different times (0, 120, 168, and 216 hours) of sourdough fermentation made with organic or conventional whole wheat flours. Total DNA of sourdough samples was extracted and the 16S rRNA gene and Internal Transcribed Spacer (ITS) region were sequenced by MiSeq-Illumina. Using this approach, the presence of lactic acid bacteria and acid acetic bacteria increased during the leavening time. Pediococcus sp. and Glutanobacter sp. were dominant in organic sourdoughs and Acetobacter sp. and Limosilactobacillus sp. in conventional sourdoughs. The fungi microbiota remained stable throughout the fermentation process, with the exception of an increase of Issatchenkia sp. at the end of the process. There were no significant differences in alpha- and beta-diversity between the organic sourdoughs and conventional sourdoughs. In conclusion, the bacterial and fungal communities in sourdoughs fermentation made with organic showed to be more stability than in conventional whole wheat flours, and changes in the composition of dominant bacterial and fungal communities occurred even after 120 and 216 hours, respectively, of backslopping.