Plant Protection (Scientific Journal of Agriculture)

Plant Protection (Scientific Journal of Agriculture)

Decontamination of fungal cultures and inhibition of bacterial growth using molasses agar

Document Type : Short communication-ٍEnglish

Authors
S. Abbasi 1
E. Seidmohammadi 2
1 Department of Plant Protection, Razi University, Kermanshah, Iran
2 Department of Plant Protection, Faculty of Agriculture, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
10.22055/ppr.2026.50779.1850
Abstract
Bacterial contamination remains one of the most persistent challenges in maintaining pure fungal cultures, often leading to data inaccuracy and the loss of valuable isolates. In this study, a natural and antibiotic-free approach was developed to overcome this issue using molasses agar, either alone or in combination with the Cabin-Sequestering (CS) physical isolation method. Sugar beet molasses, rich in phenolic and organic compounds, was incorporated into agar medium at various concentrations (75–150 g/L) and tested against multiple fungal taxa (Rhizoctonia solani, Fusarium redolens, Rhizopus stolonifer, and Pythium aphanidermatum) and two bacterial species (Bacillus subtilis and Xanthomonas translucens). The results revealed a clear dose-dependent antibacterial effect, with complete inhibition of bacterial growth at 125–150 g/L, while most true fungi maintained viable growth. In addition, molasses agar effectively supported the germination and single-spore isolation of Cercospora beticola without bacterial interference. When integrated with the CS method, molasses agar further enhanced purification efficiency, enabling the recovery of uncontaminated fungal hyphae and the establishment of stable subcultures free of bacteria. This combined system provides a sustainable, cost-effective, and environmentally safe strategy for fungal culture purification and maintenance, offering a reliable alternative to antibiotic-based techniques for mycological research.
Keywords
Polyphenol
Cabin-Sequestering method
Oomycetes
decontamination
antimicrobial effect
Subjects
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 © 2026 by the authors. Licensee SCU, Ahvaz, Iran. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0 license) (http://creativecommons.org/licenses/by-nc/4.0/.
Plant Protection (Scientific Journal of Agriculture)
Volume 49, Issue 1
Winter 2026
Pages 57-67