World Journal of Microbiology and Biotechnology, Volume 39, Issue 6 , 01/06/2023
Application of antifungal metabolites from Streptomyces philanthi RL-1-178 for maize grain coating formulations and their efficacy as biofungicide during storage
Abstract
The major safety risk of maize grain is contamination with mycotoxins. In this study, a maize-coating formulation containing freeze-dried culture filtrate of Streptomyces philanthi RL-1-178 (DCF RL-1-178) was developed and evaluated to prevent the growth of mycotoxins during maize grain storage. In vitro studies using confrontation tests on PDA plates indicated that S. philanthi RL-1-178 inhibited the growth of Aspergillus parasiticus TISTR 3276 (89.0%) and A. flavus PSRDC-4 (95.0%). The maize grain coating formulations containing the DCF RL-1-178 (0, 5, 10, and 15% (v/v)) and the polymer polyvinylpyrrolidone (PVP-K90, 4.0% (w/v)) were tested for their efficacy in In vitro and during 5 months storage. In In vitro assay, maize coating formular containing the optimum concentration (15.0%, v/v) of the DCF RL-1-178 exhibited 54.80% and 54.17% inhibition on the growth of A. parasiticus TISTR 3276 and A. flavus PSRDC-4 respectively. The inhibition was also illustrated by the microstructures of interactions between the coated maize grains with or without the DCF RL-1-178 and the fungal pathogens observed under microscope and SEM. Incorporating the DCF RL-1-178 or fungicidal Metalaxyl® into the polymer PVP-K90 maize grains coating resulted in the complete inhibition of the production of aflatoxin B<inf>1</inf> (analysed by HPLC) by the two aflatoxigenic pathogens after 5 months storage at room temperature. However, the shelf-life was shortened to only 3 months during storage at room temperature with 90% relative humidity. Overall, the application of the 10–15% DCF RL-1-178 into the maize grain coating formular provides a new alternative measure to control the mycotoxins during storage for at least 5 months. The In vitro cell cytotoxicity study showed that a concentration of 15% (v/v) or 1000 μg/mL of the DCF RL-1-178 had a strong cytotoxic effect on Vero cells. These findings indicate that DCF RL-1-178 is a potential biofungicide for controlling mycotoxins contamination in maize seed storage for planting, but not maize grain storage for animal feed.
Document Type
Article
Source Type
Journal
Keywords
Aflatoxigenic pathogenBiofungicideGrain coating formularMaize grain storageMetabolites from Streptomyces philanthi
ASJC Subject Area
Biochemistry, Genetics and Molecular Biology : BiotechnologyBiochemistry, Genetics and Molecular Biology : PhysiologyImmunology and Microbiology : Applied Microbiology and Biotechnology
Funding Agency
Thailand Research Fund
Boukaew, S., Mahasawat, P., petlamul, W., Sattayasamitsathit, S., Surinkaew, S., Chuprom, J., & Prasertsan, P. (2023). Application of antifungal metabolites from Streptomyces philanthi RL-1-178 for maize grain coating formulations and their efficacy as biofungicide during storage. World Journal of Microbiology and Biotechnology, 39(6) doi:10.1007/s11274-023-03604-5