Isolation and Identification of Cholesterol Lowering Probiotic Yeast from Palm Raffia (Raffia mambillensis) Wine

Aim: The aim of the present work was to study the cholesterol lowering effects of probiotic yeasts isolated from raffia (Raffia mambillensis) wine.

Study Design: Collection of fermented raffia wine samples, culture, isolation, identification on culture media and selection of cholesterol lowering strain in vivo and in vitro.

Place and Duration of Study: This study was conducted in the Teaching Laboratory of Life Science, Department of Biochemistry, University of Buea from February 2016 to July 2016.

Methodology: Six different palm wine samples were collected and used for selection of yeasts isolates on sabouraud Dextrose Agar using pour plate method and those with acid, bile tolerance and cholesterol assimilation in vitro selected. Strains were identified using the API 20C AUX and their cholesterol lowering effect on wistar albino rats studied. The in vivo experiment was carried out for four weeks by oral gavage; dose level 108-1010 CFU/ ml. The administered volume of each dose was 1.0 ml/kg body weight/day. After the feeding trial, the rats were dissected and serum lipid profile analyzed using biochemical kits.

Results: From six raffia wine samples, twenty eight yeasts isolates were selected based on their morphology; twelve isolates showed resistance to low pH and bile salts. Among them four isolates were able to assimilate at least 50% cholesterol in culture media and were biochemically characterized using the API® 20C AUX BioMerieux kit, which revealed 94.9%, 95.3%, 51.5% and 92.2%, homology of 1R27, 1W29, 2R29 and 3W29 with Saccharomyces cerevisiae, Candida famata, Cryptococcus neoformans and Candida famata respectively. Based on their best in vitro assimilation, strain 1R27 and 3W29 were further used for in vivo tests. Both strains showed evidence of their capacity in vivo to adhere to epithelial intestine-derived cells, reduce lipidemia (tryglyceride, total cholesterol and LDL) and increase HDL. All the two strains confirm their cholesterol lowering properties in vivo. The probiotic strains Saccharomyces cerevisiae was the most efficient on reduction of the levels of total cholesterol, LDL and VLDL in the rats blood serum compared to Candida famata.

Conclusion: These probiotic strains can therefore be used to improve the product quality and develop added value to dairy products. Hypercholesterolemia is a major risk factor for coronary artery disease and probiotics can then be suggested as tools to manage elevated cholesterol levels.