Molecular Identification and Antifungal Activity of Candida chrysomelidarum and Rhodotorula toruloides Isolated from Indonesian Indigenous Fruit Flacourtia inermis Roxb. (Lobi-lobi) against Pathogenic Mold Aspergillus flavus

Aspergillus flavus is one of the main contaminating mold species in most feed products, significantly impacting human and animal health. This study aims to isolate the epiphytic yeasts from the fruit Flacourtia inermis Roxb and test their potential ability to act as biocontrol agents for A. flavus. The antagonistic test was performed using a dual culture method, and the potential yeast isolates were then identified using a combination of morphology characterization and molecular sequence analysis. From 42 yeast isolated from F. inermis fruit, 2 yeast isolates (LCA 75 and LCA 102) demonstrated the highest inhibition growth against A. flavus (32.32 and 32.30 %, respectively). The isolates LCA 75 and LCA 102 were identified as Candida chrysomelidarum and Rhodotorula toruloides, respectively. Rhodotorula toruloides, identified as one of the yeast isolates (LCA 102), is an unconventional red yeast demonstrating notable antagonistic effects against A. flavus, inhibiting its growth by 32.30 %. This yeast, also known as Rhodosporidium toruloides, R. rubescens, R. glutinis, or R. gracilis, belongs to the subphylum Pucciniomycotina within the division Basidiomycota. The significant inhibition of mycelium growth and sporulation observed in our study highlights the potential of R. toruloides, along with C. chrysomelidarum (LCA 75), as effective biocontrol agents to reduce mycotoxin contamination in chicken feed by A. flavus. This study represents a significant advancement in the management of A. flavus contamination in animal feed. The findings not only underscore the viability of yeast-based biocontrol strategies but also contribute to a safer, more sustainable approach to preventing mycotoxin proliferation in feedstocks. HIGHLIGHTS Founding Out of 42 yeast isolates, two (LCA 75 and LCA 102) demonstrated the highest inhibition growth against A. flavus, with inhibition rates of 32.32 and 32.30 %, respectively. Identified Yeasts: LCA 75 as Candida chrysomelidarum LCA 102 as Rhodotorula toruloides (alternatively referred to as Rhodosporidium toruloides, R. rubescens, R. glutinis, or R. gracilis). Characteristics of Rhodotorula toruloides Unconventional red yeast belonging to the subphylum Pucciniomycotina within Basidiomycota. Commonly associated with various plant species and found on plant surfaces, including leaves, stems, and fruits. Identified yeast isolates exhibited inhibition activities leading to reduced mycelium growth and sporulation of A. flavus. These yeast isolates have potential as biocontrol agents to prevent mycotoxin contamination in chicken feed caused by A. flavus. GRAPHICAL ABSTRACT