Use of randomly amplified polymorphic DNA (RAPD) for characterization of dominating lactic acid bacteria in maize dough

Abstract

In previous studies Lactobacillus fermentum/reuteri was described as the dominant bacteria in the spontaneous fermentation of maize for the production of "kenkey" in Ghana. The identification methods used were not able to distinguish between these phenotypically very similar species. The present work describes the use of Random Amplified Polymorphic DNA (RAPD) for characterization of 28 isolates of dominant lactobacilli from the previous studies of maize fermentation. Cluster analysis of the RAPD profiles obtained showed the presence of two main clusters. Cluster 1 included all of the so called Lactobacillus fermentum/reuteri isolates whereas Cluster 2 comprised the remaining Lactobacillus spp. The two distinct clusters emerged at the similarity level of 60%. All isolates in Cluster 1 showed similarity in their RAPD profile to the reference strains of Lactobacillus fermentum included in the study. These isolates having two distinct bands of approximately 557 bp for the primers used, were divided into three subclusters (subspecies) indicating that several strains are involved in the fermentation and remain dominant through out the process. The present investigation has demonstrated that L. fermentum and not L. reuteri is the dominant Lactobacillus sp. of the fermentation