tailieunhanh - Báo cáo hóa học: " Process development for the elucidation of mycotoxin formation in Alternaria alternata"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Process development for the elucidation of mycotoxin formation in Alternaria alternata | Brzonkalik et al. AMB Express 2011 1 27 http content 1 1 27 o AMB Express a SpringerOpen Journal ORIGINAL Open Access Process development for the elucidation of mycotoxin formation in Alternaria alternata Katrin Brzonkalik Tanja Herrling Christoph Syldatk and Anke Neumann Abstract The black mould Alternaria alternata produces a wide diversity of mycotoxins which are of particular health concern. Since no maximum allowable limits are set for Alternaria toxins in food and feed prevention of Alternaria infestations and mycotoxin spoilage is the only way to avoid health risks. Thus the understanding of mycotoxin biosynthesis is essential. For that purpose a reliable batch process in a 2 L bioreactor was established which enables the study of several parameters influencing the production of the mycotoxins alternariol AOH alternariol monomethylether AME and tenuazonic acid TA by A. alternata DSM 12633. Modified Czapek-Dox medium was used with glucose as carbon source and ammonium and nitrate as nitrogen sources. Consumption of carbon and nitrogen sources as well as formation of the three mycotoxins were monitored the average data of five independent fermentations was plotted and fitted using a logistic equation with four parameters. Maximum mycotoxin concentrations of mg L AOH mg L AME and mg L TA were obtained. In this system the effect of different aeration rates vvm was tested which exerted a great influence on mycotoxin production. The use of the semi-synthetic Czapek-Dox medium allowed the exchange of carbon and nitrogen sources for acetate and aspartic acid. The use of acetate instead of glucose resulted in the sole production of alternariol whereas the exchange of ammonium and nitrate for aspartate enhanced the production of both AOH and AME while TA production was not affected. Keywords Alternaria alternata Mycotoxin Batch process Aeration rate Introduction Mycotoxins are secondary metabolites of .