Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 16, 2006
Publication Date: January 11, 2007
Citation: Wilkinson, J.R., Yu, J., Bland, J.M., Nierman, W.C., Bhatnagar, D., Cleveland, T.E. 2007. Amino acid supplementation reveals differential regulation of aflatoxin biosynthesis in Aspergillus flavus NRRL 3357 and Aspergillus parasiticus SRRC 143. Applied Microbiology and Biotechnology. 74(6):1308-1319. Interpretive Summary: Aflatoxins are toxic and carcinogenic compounds produced by fungal molds. They contaminate agricultural food and feed commodities. Health risks to humans and animals, as well as economic losses due to aflatoxin contamination are significant. In order to devise strategies to control aflatoxin contamination, we studied the effects of several amino acids on aflatoxin production. The amino acid tryptophan was found to decrease the amount of aflatoxin production by more than 60% in the fungus Aspergillus flavus.
Technical Abstract: Changes in aflatoxin biosynthesis in Aspergillus flavus and A. parasticus grown in yeast extract sucrose medium were compared to yeast extract sucrose media supplemented with several common amino acids. Yeast extract sucrose media supplemented with 50 mM tryptophan was found to significantly reduce aflatoxin B1 and B2 biosynthesis in A. flavus, but significantly increased B1 and G1 biosynthesis in A. parasiticus. It was also demonstrated that yeast extract sucrose cultures supplemented with 50 mM tyrosine doubled or tripled aflatoxin B1 and B2 biosynthesis in A. flavus and aflatoxins B1, B2, and G2 biosynthesis in A. parasiticus, but reduced aflatoxin G1 production by about 40%. These results indicate that the regulation of aflatoxin biosynthesis in A. flavus NRRL 3357 and A. parasticus SRRC 143 is different in response to individual amino acid, such as tryptophan and tyrosine.