Potensi Khamir Endofit Buah Markisa (Passiflora Edulis) dan Asam Organik yang Dihasilkan dalam Menghambat Aspergillus Flavus Toksigen

Abstract

Passion fruit endophytic yeasts live mutualistically in plant tissues without harming the host plant. This study aims to enumerate the population of passion fruit endophytic yeasts and their ability to produce organic acids in inhibiting the growth of Aspergillus flavus toxigen. Passion fruit was obtained from a farmer's garden in Tanjung Morawa, North Sumatra. The fruits were surface sterilized using 70% ethanol (30 min), 2% NaOCl (30 min), and rinsed with sterile distilled water (10 min). Each dilution (1 ml) was poured into a petri dish containing extract agar medium (MEA) and incubated for 5 days (29°C). Yeast coloies were enumerated and identified morphologically and biochemically. The ability of each yeast isolate to produce organic acids was done by culturing on Potato Dextrose Broth (PDB) and incubated for 10 days (29°C). A. flavus toxigenicity test was conducted using 10% coconut agar medium (CAM). Organic acid determination was done by titration. The test of organic acids and yeast isolates in inhibiting A. flavus was done by dual culture. The results showed that there were two species of endophytic yeasts, Debaryomyces hansenii and Pichia guilliermondii with populations of 8×106 and 3×106 CFU/ml, respectively. Both yeasts produced the same amount of organic acid, 96.065%. The organic acids produced by the two endophytic yeasts were able to reduce the diameter of A. flavus colonies by 36.5 and 39.2 mm respectively and were significantly different from the control treatment. Both endophytic yeast cell species were able to inhibit A. flavus colonies by 3.8 and 7.9 mm respectively compare to the control (38.2 mm).