Populasi Khamir Endofit Buah Durian (Durio Zibethinus Murr.) dan Potensinya Menghasilkan Asam Indol Asetat dan Melarutkan Fosfat

Abstract

Endophytic yeast of montong durian fruit from Langkat Regency, North Sumatera has potential to produce indole acetic acid and dissolve phosphate. A total of 25 grams of durian flesh fruit in a 1000 ml flask was added with sterile distilled water until the volume 250 ml. By using a micropipette 1 ml of the durian flesh suspension was put into a 250 ml flask containing 9 ml of sterile distilled water. Dilution was carried out until 10-15 cfu/ml. By using pour plate method, 1 ml of fruit flesh suspension was poured in a petri dish containing malt extract agar (MEA) medium. Each dilution was repeated 2 times. Each yeast cultures was incubated for 5 days (29°C). Each yeast was enumerated, isolated and identified morphologically on MEA medium and biochemically using Vitex-2 Compact. The potential of yeast species to produce indole acetic acid is carried out by culturing 10 ml of the inoculum in YMB (Yeast Malt Broth) medium that contain 0,2 grams of Ltryptophan. Cultures were incubated for 14 days (29°C) using a shaker at 110 rpm. Determination of yeast in producing IAA using a spectrophotometer (520 nm). The IAA produced was examined on 7 days of green bean gernination. Pikovskaya medium was used to determine the potential of each yeast species in dissolving phosphate. The results showed that five species of durian flesh fruit contain five endophytic yeasts, namely Brettanomyces bruxellensis, Candida ciferrii, C. parapsilosis, Kloeckera apiculata and Pichia anomala. Among of the yeast, C. parapsilosis was the highest population (11,25×1015 cfu/ml) followed by Brettanomyces bruxellensis (6,4×1015 cfu/ml). All yeast species have potential to produced IAA and Candida ciferrii produces the highest (3,87 ppm) followed by K. apiculata (3,61 ppm). The highest phosphate solubility occurred on Candida ciferrii with a clear zone of 9,60 mm with a phosphate solubility index of 1,03.