Screening and molecular characterization of cholesterol-lowering lactic acid bacteria isolated from African oil palm wine (Elaeis guineensis) and corn beer.

Abstract

Background: High serum cholesterol is a risk factor for cardiovascular disease (CVD), leading to many fatalities. Probiotic supplementation improves health benefits by lowering serum cholesterol. African oil palm (Elaeis guineensis) wine and corn beer have been described as potential sources of probiotic bacteria, but their cholesterol lowering activity has not been extensively investigated. Therefore in this study, we isolated and characterized lactic acid bacteria with probiotic and cholesterol lowering properties from these sources.Methods: A total of fifty lactic acid bacteria (LAB) were isolated from palm wine and corn beer using de Man Rogosa and Sharpe (MRS) agar by pour plate method. Catalase negative and Gram positive colonies were considered as presumptive LAB. For probiotic properties and selection, acid and bile salt tolerance were evaluated based on viable colony count on MRS agar and cholesterol assimilation from culture media was performed by spectrophotometry. The data analysis was performed by One Way Analysis of Variance and p value< 0.05 was considered significant. The isolates with excellent cholesterol assimilation properties were selected and identified with species of morphology and biochemical analysis using API 50 CHL kit and genotypic identification by sequencing of 16 S rRNA gene.Results: Fifty isolates had morphological features similar to LAB. They were catalase negative and Gram positive colonies. Among the fifty isolates, five were considered as acid and bile tolerant (viable count exceeded 6logCFU/ml), with two isolates having excellent cholesterol assimilation property (>80%). The result obtained using API 50 CHL kit did not agree with the genotypic identification which was used to confirm the identity of the isolates as most closely related to Lactobacillus brevis ATCC (Accession No.NR116238) and Enterococcus faeccium NBRC (Accession No. NR113904).Conclusions: The two strains isolated from traditionally fermented drinks in Buea can be considered as potential probiotics. They can therefore be used to formulate food supplement needed to lower cholesterol in hypercholesterolemia patients.

Potentials of Palm Wine as Probiotics and Organic Acids Source in Animal Nutrition

“…Similar inhibitory responses had been reported against diarrhoeagenic pathogens such as Salmonella typhi, Shigella dysentariae, Staphylococcus aureus and E. coli, compared to known antibiotics using a 7-day old fermented Raphia wine 83 . The responses observed may not be unconnected with the increased concentrations of metabolic products of wine fermentation such as lactic acid, acetic acid, alcohol, fatty acids and antimicrobial substances (bacteriocin, reutericyclin, mitoxantrone) known for their anti-microbial, immune-modulatory, anti-diabetic, anti-cancer, and cardio-circulatory functions 32,64,80,139,142,143 . The production of short-chain fatty acids particularly lactic and acetic acid by the LABs and AABs induces an unfavourable micro-environment inimical to the survival of intestinal pathogens through gut pH reductions 144,145 .…”

“…Yeast isolates from palm wine have shown strong antimicrobial activities against pathogenic organisms such as Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella spps. 139,140 . A study by Ojo and Agboola 141 , observed that fermented palm wine of Raphia vinifera and Elaeis guineensis had an inhibitory effect against Salmonella typhi compared to antibiotic drugs like chloramphenicol, amoxicillin, Gentamicin and ciprofloxacin.…”