Mycotoxins and Invertase Enzyme of the Mycoflora of Molasses in Upper Egypt

Abstract

A total of twenty-nine species and one species variety belonging to 12 genera was isolated from 30 samples of molasses on 1% glucose (10 genera, 22 species and 1 variety) and 50% sucrose (7, 21 and 1) Czapek’s agar at 25°C media. Aspergillus, Mucor, Mycosphaerella and Pénicillium were the most common genera on the two types of media. From the above genera, the most prevalent species were: Aspergillus flavus, A fumigatus, A niger, Mycosphaerella tassiana, Pénicillium chrysogenum, P oxalicum and P purpurogenum Also, some species were only isolated on 50% sucrose such as Eurotium amstelodami, E. chevalieri, E. repens, Humicola fuscoatra, Penicillium aurantiogriseum and P puberulum About 65 fungal isolates isolated from 50% sucrose agar were tested for their ability to produce invertase enzyme in liquid medium and 93.8% of the isolates could produce this enzyme. From the positive isolates, 32 showed high invertase activity, 21 had moderate activity and the remaining 8 isolates were of weak activity. Sixty isolates of Aspergillus, Emericella, Eurotium, Mycosphaerella and Penicillium from the preceding study were screened for the presence of their respective mycotoxins. Larva of brine shrimp (Artema salina L.) were used for toxicity test of the fungal crude extracts. Three isolates out of 60 tested were toxic. Using thin-layer chromatographic technique, 5 different known mycotoxin were detected aflatoxins : B1, B2, G1, G2 and citrinin.