Characteristics of Saccharomyces Cerevisiae Isolated from an Indigenous Fermented Beverage (Burukutu) as Potential Brewer’s Yeast for Beer Production

Beer is one of the regular drinks produced and consumed in many countries including Nigeria. Its cost has become so high making it unaffordable to low income earners. One major reason for the high cost of beer is the cost of imported brewer’s yeast. The potential application of Saccharomyces cerevisiae isolated from burukutu (a Nigerian local fermented beverage drink) was investigated. The Sorghum variety used in this study was developed from Sk5192 variety obtained from the Institute of Agricultural Research Zaria, Nigeria. Burukutu sample was purchased from community market in Enugu State, Nigeria. Standard Microbiological techniques were employed in the isolation, characterization and identification of the yeasts. Beer production attributes such as stress exclusion, flocculation, hydrogen sulphide production, yeast viability and consistency tests were checked. The yeast isolated from burukutu (SBB) exhibited identical morphological characteristics as the control brewer’s yeast (SCT), showed multiple budding capacities and fermented all tested sugars except melibiose and raffinose. The flocculation capacity and viability rate of SBB was recorded as 82% and 83% respectively against the control yeast (SCT) which was 82% and 91%. None of the isolates produced hydrogen sulphide when tested. Malt production involving steeping, germination, kilning, preparation of wort for alcohol production, inoculum development and pitching were the processes used in the laboratory beer production. Properties of the beers produced with SBB and SCT showed that the specific gravity of the fermented wort for SBB and SCT were the same with no significant difference (1.010 and 1.010). The apparent and real extract of the isolated yeast (SBB) were 6.70% and 8.50% respectively and the control yeast (SCT) recorded 4.80% and 6.55% which were greater than the standard minimum values (2.50%, 4.40%) for extra strong beer. The pH values of beer produced with SBB and SCT fell within the standard value of 36-48 for normal beer. Thus, Burukutu can be a good source of Saccharomyces cerevisiae which can be enriched and used for industrial and home brewing.