Abstract

This study was attempted to know that the interactions of various fungi, and methionine and MgSO4 introduced as the substrate of culture media for fungi were affected to produce aflatoxins by Asp. flavus. 5 different fungi were isolated from the fermented soybean mash and were cultured in Chemically Defined medium (C.D. media) and soybean mash at 25 degrees for 10 days. (1) It was confirmed that Asp. flavus produced aflatoxins in the C.D. medium and soybean mash, but that Asp. niger, Asp. oryzae, Asp. awamori and Asp. terreus did not produced them respectively. (2) Asp. flavus cultured with Asp. niger did not produce aflatoxins in C.D. medium, but produced in soybean mash, in other hand, Asp. flavus with other fungi except Asp. niger produced aflatoxins in C.D. medium and soybean mash. (3) The growth of fungi were more prosperous in the separate culture than in the mixed culture. (4) In the C.D. medium added 20% of cultured medium of Asp. niger, Asp. flavus did not produce aflatoxins but other cultured medium did not prohibit the production of aflatoxins by Asp. flavus. (5) On the contrary, MgSO4 increasing the productivity of aflatoxins by Asp. flavus in the C.D. medium methionine known as one of precurser of aflatoxins did not affected the increasing productivity with significance.