Studies on an Actinomycete Producing a Melanin Pigment Inhibiting Aflatoxin B1 Production by Aspergillus flavus

Thirty different isolates of actinomycetes collected from different localities in Gharbia Governorate, Egypt were tested for melanin pigment production. Only one isolate produced melanin and identified as Streptomyces torulosus. The selected actinomycete isolate was grown under different cultural conditions and it was found that starch-nitrate medium was the optimum for the growth of selected isolate at pH 7.0 after 10 days of incubation at 30 ̊C. Increasing the L-tyrosine concentration in tyrosine liquid medium induced tyrosinase and enhanced the growth of the isolate and the ability of pigment production. The pigment was purified, characterized by physical and chemical properties and identified as melanin. In vitro aflatoxin B1 production by Aspergillus flavus was reduced with the increase of pure melanin pigment concentration up to 0.1g/100 ml culture (0.1%), after that the aflatoxin B1 production was completely inhibited with the increase of pure melanin pigment concentrations as compared with the control. In Vivo studies, the aflatoxin B1 concentration in wheat grains reduced with the increase of pure melanin pigment as compared with control. [Mohamed Tawfiek Shaaban, Sabha Mahmoud Mabrouk El-Sabbagh and Asmaa Alam. Studies on an Actinomycete Producing a Melanin Pigment Inhibiting Aflatoxin B1 Production by Aspergillus flavus. Life Sci J 2013; 10(1):1437-1448]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 214