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Mold is one of the microorganisms that causes damage to cocoa fruit because it produces mycotoxins as secondary metabolites that can decrease the crop yield. One type of pathogenic mold that destroys cocoa fruit is Aspergillus flavus. A. flavus produces aflatoxin B1 which is the most potent hepatotoxin and carcinogen to humans. Amongst the most effective ways to avoid alpha-toxin contamination in cocoa beans is to inhibit the growth of A. flavus in the beans. However, the use of pesticides and fungicides can increase the development of resistant strains of fungi and have a negative impact on the environment and human health. Therefore, we need other alternatives such as bio-control agents using antagonistic microorganisms, including yeasts. Thus, this study aims to characterize yeasts isolated from the fermented cocoa beans (Theobroma cacao) from Lampung, Indonesia, and evaluate their ability to inhibit the growth of Aspergillus flavus UNJCCF-55. The methods used were yeast screening, dual culture technique for antagonistic test, and morphological characterization. The 37° C-growth screening gave 89 out of 98 yeast isolates. The subsequent antagonist test resulted in 13 isolates with the highest inhibition zone against A. flavus UNJCCF-55. These yeast isolates were macroscopically of smooth surface, butyrous texture, milky white color, irregular edges, and convex elevation. Microscopic observation showed that the isolates have oval cell shape, asexual reproduction of budding, and non-hyphae structure. [ABSTRACT FROM AUTHOR]

The presence of pathogenic molds in post-harvested cocoa beans poses a significant problem to most Indonesian farmers. Pathogenic molds secrete phytopathogenic toxins which cause rotting, seriously damaging the cocoa fruits. The common pathogenic molds found in damaged cocoa beans are Phytophthora palmivora and Phytophthora megakarya. These molds are so far controlled by using chemical pesticides, whose long-term use is potentially harmful to human health and the environment. Thus, a healthier and safer alternative is needed, especially using biological agents such as yeasts. Some yeasts produce cellulose-degrading enzymes that can possibly break down the fungal cell wall which is composed mostly of the polysaccharide's chitin and glucan. In this study, yeasts were isolated during the cocoa fermentation process, followed by screening for cellulolytic activity using direct planting and paste method, and subsequent antagonistic testing by double culture technique. Out of 128 yeast isolates, 77 possessed cellulase activity, with 6 of them having the highest activity index. Antagonistic activity test of these 6 isolates (C1.0.4, C1.1.3, C2.3.10, C2.3.14, C3.5.11, and C3.3.1) against the pathogenic molds resulted in isolate C3.3.1 showing the highest inhibition percentage from the 2nd to 8th day of incubation. [ABSTRACT FROM AUTHOR]

Dark Septate Endophytes (DSE) are a group of ascomycetes that live in intracellular and extracellular root tissue to facilitate plant growth and stress tolerance in extreme environments. However, little is known about the DSE fungi isolated from certain plant roots such as Pteris vittata, especially under drought condition. Pteris vittata is known for its ability to live in various types of substrates and ecosystems. In this study, we obtained DSE fungi from the fern roots Pteris vittata collected from the area of Universitas Negeri Jakarta. DSE isolation was carried out by inoculating the Pteris vittata fern roots with a size of 0.5 cm on the surface of sterilized PDA media for 5-7 days at 27°C. Observations were made every 24 hours using a stereo microscope to see the first hyphae appeared from the plant roots. The results exhibited 13 samples of roots with hyphae colonization and were suspected to be DSE fungi. Of the 13 root isolates, only 3 isolate (PP2, PP4A, and PPB) showed the DSE growth (23%) with melanin pigment. The morphological characteristics of endophytic DSE fungi collected from Pteris vittata roots represented septate hyphae, brownish to black colony color, a growing zone, and a velvety texture. For the isolate PP2, it showed sclerotia while for the isolate PP4, it exhibited light brown colonies. [ABSTRACT FROM AUTHOR]