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Enhancing itaconic acid production by Aspergillus terreus
Gregor Tevz1, Mojca Bencina, Matic Legisa
1National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
Applied Microbiology and Biotechnology
|May 13, 2010
Summary
Genetic modification of Aspergillus terreus with a deregulated 6-phosphofructo-1-kinase (PFK1) gene from Aspergillus niger enhanced itaconic acid production. This strategy boosts itaconic acid yields by improving anaplerotic reactions.
Area of Science:
- Biotechnology
- Metabolic Engineering
- Industrial Microbiology
Background:
- Aspergillus terreus is a key microorganism for industrial itaconic acid production.
- Itaconic acid biosynthesis is linked to the tricarboxylic acid (TCA) cycle, with anaplerotic reactions potentially enhancing production.
- Upregulated glycolysis, driven by a modified 6-phosphofructo-1-kinase (PFK1), serves as an anaplerotic pathway in Aspergillus niger.
Purpose of the Study:
- To enhance itaconic acid production in Aspergillus terreus by introducing a modified PFK1 gene.
- To investigate the effect of deregulated glycolytic flux on itaconic acid synthesis and excretion.
- To bypass complex posttranslational modifications by engineering a functional, shorter PFK1 fragment.
Main Methods:
- Genetic modification of Aspergillus terreus by inserting a synthetically engineered Aspergillus niger pfkA gene.
- Creation of a shorter, active PFK1 fragment resistant to citrate inhibition.
- Cultivation of transformants under conditions favoring itaconic acid accumulation.
Main Results:
- Transformed Aspergillus terreus strains exhibited increased specific productivities of itaconic acid.
- Higher final yields of itaconic acid were observed in the engineered strains compared to the parental strain.
- Growth rates of all transformants were suppressed, likely due to the low initial pH required for itaconic acid accumulation.
Conclusions:
- Engineering Aspergillus terreus with a modified Aspergillus niger pfkA gene effectively enhances itaconic acid production.
- The strategy of deregulating glycolysis via PFK1 modification is a viable approach for improving industrial fermentation yields.
- Further optimization may be needed to address suppressed growth rates while maintaining high itaconic acid productivity.
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