Effect of some Physical Factors and Bread Yeast Saccharomyces cerevisiae on Asperigillus flavus and A. Parasiticus Growth and Aflatoxine B1 Production

Abstract

Laboratory experiments were carried out in the postgraduate laboratories, Biology Department – College of Education / Kerbala University . The Study aimed to assess the effect of some environmental factors such as temperature, pH and efficiency of Saccharomyces cerevisiae in the radial growth of Asperigillus flavus and A. parasiticus and production aflatoxin B1. Results showed that,the temperature 300C was the best for fungal growth and their production from afla B1, where the mean diameter of the colony was 9 cm followed by 200C giving 2.83 and 3.04 cm for A. flavus andA. parasiticus respectively . Increasing and decreasing temperature from this rang caused adecrease in the fungal growth as well as their production of Afl B1. The best pH for fungal growth was 7.5 whose the no did growth of A.flavus and A. parasiticus was 6.29and 6.50cmrespectively followed pH 9.5 giving 5.09 and 5.29cm for A. flavus and A. parasiticus respectively .On the other hard . No growth was obtained at pH 3.5 . The afla B1 did not appeared with pH 3.5 , mean while it appeared with pH 5.5 , 7.5 and 9.5 . Results pointed that, the efficiency of Saccharomyces cerevisia in the inhibiting of radial growth of A. flavusand A. parasiticus was 100% at 3 and 2g/L and 91.60% at 1g/L in the A. flavus and 75.00 and 70.33% at 3 and 2g/L and respectively 56% at 1g/L for A. parasiticus , and The afla B1 did not appeared with treatment of A. flavus with 1,2and 3 g/L from Saccharomyces cerevisia extract while it appeared with treatment of A. parasitic with 1,2 and 3 g/L from Saccharomyces cerevisiea extract .