Glass bead system to study mycotoxin production of Aspergillus spp. on corn and rice starches

• Published in: Applied microbiology and biotechnology 2024-12, Vol.108 (1), p.348, Article 348
• Main Authors: Inotai, Katalin, Bata-Vidács, Ildikó, Tóth, Ákos, Kosztik, Judit, Varga, Mónika, Szekeres, András, Nagy, István, Dobolyi, Csaba, Mörtl, Mária, Székács, András, Kukolya, József
• Format: Article
• Language: English
• Subjects: Aflatoxin B1; Aflatoxin B1 - biosynthesis; Aflatoxin B1 - metabolism; Aflatoxins; Air flow; Amylopectin; Amylose; Aspergillus; Aspergillus - metabolism; Aspergillus flavus - metabolism; Biomedical and Life Sciences; Biotechnology; Carbon; Carbon sources; Carcinogens; Corn; Energy resources; Energy sources; Environmental Biotechnology; Food sources; Glass; Glass beads; Glucose; Life Sciences; Microbial Genetics and Genomics; Microbiology; Microscopy, Electron, Scanning; Mold; Mycotoxins; Mycotoxins - biosynthesis; Mycotoxins - metabolism; Oryza - chemistry; Particle Size; Rice; Scanning electron microscopy; Starch; Starch - metabolism; Starches; Sterigmatocystin; Sterigmatocystin - biosynthesis; Sterigmatocystin - metabolism; Surface area; Toxins; Vegetables; Zea mays - chemistry
• ISSN: 0175-7598; 1432-0614; 1432-0614
• DOI: 10.1007/s00253-024-13190-7

Mycotoxin production by aflatoxin B1 (AFB1) -producing Aspergillus flavus Zt41 and sterigmatocystin (ST) -hyperproducer Aspergillus creber 2663 mold strains on corn and rice starch, both of high purity and nearly identical amylose-amylopectin composition, as the only source of carbon, was studied. Scanning electron microscopy revealed average starch particle sizes of 4.54 ± 0.635 µm and 10.9 ± 2.78 µm, corresponding to surface area to volume ratios of 127 1/µm for rice starch and 0.49 1/µm for corn starch. Thus, a 2.5-fold difference in particle size correlated to a larger, 259-fold difference in surface area. To allow starch, a water-absorbing powder, to be used as a sole food source for Aspergillus strains, a special glass bead system was applied. AFB1 production of A. flavus Zt41 was determined to be 437.6 ± 128.4 ng/g and 90.0 ± 44.8 ng/g on rice and corn starch, respectively, while corresponding ST production levels by A. creber 2663 were 72.8 ± 10.0 µg/g and 26.8 ± 11.6 µg/g, indicating 3–fivefold higher mycotoxin levels on rice starch than on corn starch as sole carbon and energy sources. Key points • A glass bead system ensuring the flow of air when studying powders was developed . • AFB1 and ST production of A. flavus and A. creber on rice and corn starches were studied . • 3–fivefold higher mycotoxin levels on rice starch than on corn starch were detected .