Exploring the Microbial Diversity of Botswana’s Traditional Sourdoughs

Abstract

Sourdough is one of the oldest technologies employed by humans to leaven bread because of its ability to enhance the flavour and structure of bread using micro-organisms. However, there is a lack of comprehensive information in Botswana regarding the diversity of sourdough starters and the fermentative micro-organisms responsible for spontaneous fermentation. The present study aimed to explore the microbial species diversity of sourdoughs in Botswana and gain insight into the unique microbial communities involved in sourdough production. A total of nine samples were collected from different areas in Botswana. The microbial diversity in sourdoughs was characterized through the sequencing of amplicons of the 16S ribosomal DNA and internal transcribed spacer regions. In silico polymerase chain reaction–restriction fragment length polymorphism and phylogenetics were utilized to determine the genetic diversity among the isolates. The dominant yeast species identified were Saccharomyces cerevisiae, Wickerhamomyces anomamlus, Pichia kudriazverii and kazachstania humilis. Additionally, the presence of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Liquorilactobacillus nageli and Bacillus cereus was also detected. It is worth noting that two species of acetic acid bacteria (AAB), namely Acetobacter pasteurianus and A. indonesiensis, were isolated, though in low levels, but the finding is significant in sourdough fermentation. The low occurrence of AAB (acetic acid bacteria) species observed in this study could be an important finding, as these bacteria are considered understudied, yet they are known to contribute significantly to the final product.