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This study aimed to determine the viability of yacon extract-based agar (YEBA) as a substitute medium for micro-organisms. Three (3) species of bacteria were tested in this study: Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The study involved the inoculation of these bacteria on Yacon extract-based agar at controlled environment conditions.
The yacon extract was prepared by treating the yacon juice with 95% ethanol for 72 hours then evaporating the alcohol using the rotavap. The resulting mixture was diluted into four concentrations: 25%, 50%, 75%, and 100% and were mixed with an appropriate amount of pharmaceutical agar to form the yacon extract-based agar. The pH of the YEBA was adjusted to 7.0 before inoculation with the test bacteria. Bacterial growth was determined through the number of colonies grown after overnight incubation at 370C.
The results of the experiment revealed that all the YEBA preparations showed signs of bacterial growth. It further revealed that the 75% and 100% extract concentrations exhibited the most significant number of colonies. Likewise, the colonies manifested characteristic pigments. Finally, it can be concluded that the Yacon extract-based agar, using ethanol as the extracting solution, can be used as a cheap and cost-effective substitute culture medium for micro-organisms.