Molecular characterization of probiotic Enterococcus hirae from fermenting acalypha wilkesiana (Irish Petticoat) and Talinum triangulare (Water Leaf) medicinal plants

Abstract

Research on lactic acid bacteria (LAB) continues to be relevant in the development of nutraceuticals. In this study, edible medicinal Talinum triangulare and Acalypha wilkesiana were collected and subjected to spontaneous fermentation for 24 h. Samples were collected at 6 h intervals for determination of pH and microbial analysis. Determination of LAB percentage frequency occurrence, probiotic properties, and safety were done. Molecular characterization of probiotic and safe LAB was carried out.  During spontaneous fermentation of T. triangulare, pH decreased from 7.7 at 0 h to 5.8 at 24 h. Same trend was observed during A. wilkesiana fermentation. Microbial loads increased from 1.4 × 103 cfu/ml at 6 h to 4.68 × 107 cfu/ml at 24 h during fermentation of water leaf and from 2.56 × 102 cfu/ml at 6 h to 5.85 × 107 cfu/ml at 24 h during Irish petticoat fermentation. Forty-three LAB (30 and 13 LAB from fermenting Water leaf and Irish petticoat, respectively) were isolated in this study. They were identified as: Enterococcus hirae (43.3%), Streptococcus thermophilus (20.9%), Enterococcus durans (18.6%), and Lactococcus lactis (14.0%). However, Enterococcus hirae had the highest probiotic properties followed by Streptococcus thermophilus but the result of their molecular characterization revealed Enterococcus hirae and Weisella confuse, respectively. Considering this confusion and uncertainty about W. confusa, its use as a probiotic should be approached with caution. E. hirae is suggested to be the best probiotic potential starter for the controlled fermentation of water leaf and Irish petticoat medicinal plants. This study therefore confirms the possibility of isolating probiotic E. hirae from non-dairy source and suggests its incorporation into plant-based starter fermented foods.   Key words: Enterococcus hirae, Weisella confusa, probiotic, water leaf, Irish petticoat.