The filamentous fungus Aspergillus pseudoterreus has been successfully used for industrial production of itaconic acid for many years. In this study, we investigate its new application-producing aconitic acid. Aconitic acid is used as nutty flavor in food industry. In A. pseudoterreus, when cad (cis-aconitic acid decarboxylase) is deleted, itaconic acid production is completely abolished, while 7g per liter aconitic acid is detected. In order to increase the production of aconitic acid, we overexpressed the aconitase, mitochondrial organic acid transporter (mttA) and MFS (Major Facilitator Superfamily) type transporter (mfs) in the cad deletion background. There is no significant effect on aconitic acid production level. We hypothesize that the aconitic acid transport across plasma membrane is already saturated. We will do comparative proteomics analysis on membrane proteins in both wild type and cad deletion stains to target the candidate transporters. Deletion assay will then make further confirmation. Lastly the overexpression of the transporter will be expected to significantly increase aconitic acid secretion from A. pseudoterreus cad deletion strain.
Full conference title:
- Fungal Genetics Conference 30th (2019)