Screening of secondary metabolites produced in liquid culture conditions from aspergillus brasiliensis

In this thesis, effects of variable culture conditions and media components on secondary metabolites produced by Aspergillus brasiliensis in liquid culture fermentation were investigated. Experimental design was applied for three different values of temperature, agitation speed, pH and C/N ratio to determine which conditions were more effective on secondary metabolite production and diversity. After screening, the best results were obtained when the temperature was 25 °C, shaking speed 210 rpm, pH 6 and C/N ratio 32. In order to examine the effect of different carbon and nitrogen sources, the productions were made with combinations of six different carbon and five different nitrogen sources based on YES broth medium. The highest secondary metabolite diversity was observed in sucrose and CSL medium. Combinations of iron, manganese, copper and zinc were tested in sucrose & CSL medium under the determined conditions in order to see the effect of trace elements. In conclusion, there is no significant difference between the media in terms of secondary metabolite profiles. Keywords: Aspergillus brasiliensis, secondary metabolites, submerged fermentation, experimental design.