THE EFFECT OF YEAST ANTAGONIST ISOLATED FROM THE FERMENTATION OF COCOA BEANS (Theobroma cacao) FROM LAMPUNG, INDONESIA, ON THE GROWTH OF Aspergillus flavus UNJCC F-55
Dalia Sukmawati1,2, Alika Firhandini1, Siti Nurkhasanah1, Umi Khumaiya1, Atin Supiyani1, Shabrina Nida Al Husna3 ,Hesham El Enshasy4,5, Daniel Joe Dailin4, and Catur Sriherwanto6

1 Biology Department, Laboratory of microbiology, 9th Floor Hasyim Ashari Building, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta, Indonesia- Dalia-Sukmawati[at]unj.ac.id
2.Universitas Negeri Jakarta Culture Collection, Laboratory of microbiology, 9th Floor Hasyim Ashari Building, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta, Indonesia- Dalia-Sukmawati[at]unj.ac.id-

1 Biology Department, Laboratory of microbiology, 9th Floor Hasyim Ashari Building, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta, Indonesia- allika.firhandini.bioa17[at]gmail.com

1 Biology Department, Laboratory of Microbiology, 9th Floor Hasyim Ashari Building, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta, Indonesia- sitinurkhasanah68[at]gmail.com

1Biology Department, Laboratory of microbiology, 9th Floor Hasyim Ashari Building, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta, Indonesia- umikhumaiya_1308617072[at]mhs.unj.ac.id

1Biology Department, Laboratory of microbiology, 9th Floor Hasyim Ashari Building, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta, Indonesia- atinsupiyani78[at]gmail.com
3 Department of Microbiology, School of Life Sciences and Technology, Institut Teknologi Bandung, Bandung, Jawa Barat, Indonesia- shabrina.nida[at]gmail.com
4Institute of Bioproduct Development, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru, Malaysia- henshasy[at]ibd.utm.my
4Institute of Bioproduct Development, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru, Malaysia- Email: jddaniel[at]utm.my
5City of Scientific Research and Technology Applications, New Burg Al Arab, Alexandria, Egypt- Email:henshasy[at]ibd.utm.my
6Centre for Applied Microbiology, National Research and Innovation Agency (BRIN), Science and Technology Park, Banten, Indonesia- catur.sriherwanto[at]brin.go.id

Abstract

Mold is one of the microorganisms that causes damage to cocoa fruit because it produces mycotoxins as secondary metabolites that can lower 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 way 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 aimed at characterization of yeasts isolated from the fermented cocoa beans (Theobroma cacao) from Lampung, Indonesia, and evaluation of their ability in inhibiting the growth of Aspergillus flavus UNJCCF-55. The methods used were yeast screening, dual culture technique for antagonistic test, and morphological characterization. The 37º 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 colour, irregular edges, and convex elevation. Microscopic observation showed the isolates having oval cell shape, asexual reproduction of budding, and non-hyphae structure

Keywords: cocoa bean fermentation, yeasts, A. flavus, antagonistic activity

Topic: Biology