Molecular characterization of lactic acid bacteria isolated from starter dough of Sudanese sorghum fermented flat bread (Kissra)

Abstract

Objective: The purpose of this study was to isolate and characterize LAB from fermented kissra dough by both classical and PCR-based molecular methods to identify the isolates to sub-species level which may help to formulate starter culture as well as in the biological preservation of foods. Materials and Methods: Both classical and PCR-based molecular methods were used to identify the LAB isolates. A total of 75 lactic acid bacteria (LAB) isolates have been recovered from fermented kissra dough and characterized at strain level with molecular tools. RAPD analysis was performed initially to cluster the isolates using two different primers R2 and M13. Species identification was based on sequence analysis of 16S rRNA gene. Nine cluster of LAB PCR products sequenced and subjected to nucleotide BLAST. Results: Four percent (4%) (3 isolates), (Group1L) showed 100% homology towards Pediococcus acidilactici and 6.7% (5 isolates), (Group 9L) showed 100% homology towards Lactococcus lactis subsp lactis strain SFL. Among the rest of the 67 lactobacillus isolates, 1.6% (1 isolate), (Group 2L) showed 100% homology towards L. murinus, also same percentage (1.6%) (Group 4L) reported as L. casei strain IMAU70007. 2.9% (2 isolates), (Group 5L) showed 100 homology towards L. plantarum strain KLAB4. The same percentage (2.9%) (Group 8L) were showed 100% similarity towards L. fermentum, 5.9% (4 isolates), (Group 7L) showed 100% homology towards L. casei strain SWU30436, 20.9% (14 isolates), (Group 3L) showed 100% similarity towards L. plantarum strain 1.0557CGMCC, while the majority of the isolates (64.2%) (43 isolates), (Group 6L) showed 100% homology towards L. plantarum strain CSI7. Phylogenetic analysis was performed using software MEGA 6.0. Conclusion: Several different species of lactic acid bacteria can be implicated in the fermentation of kissra. The starch-fermenting strains might be important to formulate starter cultures and for use commercially in the production of kissra.