Characterization of potential probiotics isolated from fermented under-utilized Chrysophyllum albidum Linn kernels using microbiological, biochemical and molecular techniques

Abstract

Chrysophyllum albidum is a crop of commercial value in Nigeria, however, the seeds are either used for local games or thrown away. This study aimed at exploring this under-utilized kernel as a novel source for obtaining health beneficial bacteria with desired probiotic characteristics. Isolation of potential probiotic bacteria from naturally fermented C. albidum seeds was carried out and followed by their safety evaluation, Gram staining, catalase test, acid tolerance, bile tolerance, cellular hydrophobicity and auto-aggregation assays. 16S rRNA sequencing and the detection of bile salt hydrolase (bsh) gene were the molecular methods applied for the bacteria characterization. Three potential probiotic bacteria were isolated from the fermented seeds. All isolates were non-haemolytic, Gram positive cocci, and catalase negative, grew in 1% bile, acidic pH of 3.5, and showed good auto-aggregation property. 16Sr RNA sequencing revealed isolates to be strains of Enterococcus durans, and the bsh gene was detected in all the strains. In conclusion, novel naturally fermented foods as seen in the fermented C. albidum kernels can serve as sources for the isolation of probiotic bacteria with great interest, and thus serve as starter culture to improve the organoleptic property of dairy and non-dairy foods.