Growth and extracellular enzyme production by microorganisms isolated from Ugba - an indigenous Nigerian fermented condiment

Studies were conducted to isolate and identify the fermenting microorganisms of ‘Ugba’, an indigenous Nigerian fermented food condiment. The isolated microorganisms were screened for amylase, protease and lipase production, the activity and specific activity of the enzymes were also determined. The effect of pH and temperature on the activity of the enzymes was also studied. The following groups of organisms were identified as among the major fermenting organisms isolated from fermenting ‘Ugba’; Bacillus species, Proteus species, Staphylococcus species, Micrococcus species and Pseudomonas species. Bacillus, Staphylococcus and Proteus were positive for amylase production. Bacillus subtilis, B. licheniformis and Staphylococcus species exhibited the highest potential for amylase production. Maximal amylase activity was achieved within the pH range of 6 to 7, while the optimum temperature range for the enzyme activity was between 50 to 60°C. Twelve isolates identified as Bacillus subtilis (Bs1, Bs2, Bs3, Bs4, Bs5, Bs6 and Bs7) and Bacillus lichenformis (Bl1, Bl2, Bl3, Bl4 and Bl5) were identified as among the major fermenting organisms. These isolates tested positive for protease enzyme production with the highest protease activity shown by Bs3 (18.48 ul/ml) and the least by Bl2 (4.21ul/ml) and Bl3 (4.28 ul/ml). Highest protease activity (18.48 ul/ml) was recorded at the end of the third day of incubation. The optimum temperature for protease activity was observed to be within 35 to 40°C, while the optimum pH range for the enzyme activity was recorded at pH 7 to 8. Screening of the isolated organisms for lipase production revealed that Micrococcus species, Pseudomonas species and a strain of Bacillus subtilis (Bs2) were able to produce lipase enzyme. The study evaluated the potential of the strains in starter culture development for fermentation of African foods.Keywords: Ugba, fermentation, amylase, protease, lipase, enzyme activityAfrican Journal of Biotechnology Vol. 12(26), pp. 4158-416

Production of Table Wine from Processed Tea Bags Using Different Strains of Saccharomyces cerevisiae

Wine samples were produced from locally available tea infusions (Lipton tea, Top tea and Highland tea) using baker’s yeast (Saccharomyces cerevisiae By1) and yeast cultures from pineapple (S. cerevisiae Py6) and cocoa (S. cerevisiae CY43). Physicochemical analyses and microbial evaluation were undertaken during fermentation. Lipton tea wine produced,using baker’s yeast, pineapple yeast and cocoa yeast had highest alcoholic contents of 7.88%, 6.25% and 7.20%, respectively. Top tea wine produced using the same set of yeasts had highest alcoholic contents of 9.78%, 5.43 and 8.15% respectively, while Highland tea wine produced highest alcoholic contents of 9.78%, 7.07% and 7.61% respectively.  Physicochemical analyses for all the wines produced showed that the specific gravity, total solids and pH of the must decreased as fermentation progressed while the titratable acidity remained constant throughout the must fermentation. Colony counts showed a high biomass of yeast cells that decreased as it tended towards the end of fermentation. Sensory analysis of the wines showed that Lipton and Top tea are the most acceptable organoleptically when compared with the commercial wine used as control although the three tested teas were not significantly different statistically. Baker’s yeast was rated as the best yeast for wine fermentation irrespective of the type of tea used. All the wines produced were generally accepted as they were scored above average. This study highlights the potential of using different tea infusions as alternatives to grape and other fruit musts in wine making. It also confirms that commercial yeasts such as baker’s yeast can be used in homemade wine production.Keywords: Wine production, Table wine, beverage, tea bags, Saccharomyces cerevisiae