In human nutrition, dietary fibers are un-degradable by mammalian enzymes, and are therefore potentially available for fermentation by microorganisms living in the gastrointestinal tract. It is thought that these fermentable carbohydrates affect fermentation by stimulating the growth or metabolism of specific bacterial species, which are potentially beneficial for health. Hence in this study three gut associated microbes-Escherichia coli, Bacillus subtilis, and Lactobacillus acidophilus were made to ferment the non-digestible fraction of Otili-Sphenostylis stenocarpa, a well-established underutilized wild bean with high economic importance. After 18 hours' fermentation period short chain fatty acids (SCFAs) and medium chain fatty acids (MCFAs) were detected and evaluated by GC-MS analysis. Metabolic products were relatively dependent on the fermenter. This present study affirmed butyric acid as the main SCFAs after 18 hours' fermentation. The clinical significance of thirteen other MCFAs detected and quantified was also explored thus conferring a valuable prebiotic on Otili.