Abstract
BackgroundItaconic acid, which has been declared to be one of the most promising and flexible building blocks, is currently used as monomer or co-monomer in the polymer industry, and produced commercially by Aspergillus terreus. However, the production level of itaconic acid hasn’t been improved in the past 40 years, and mutagenesis is still the main strategy to improve itaconate productivity. The genetic engineering approach hasn’t been applied in industrial A. terreus strains to increase itaconic acid production.ResultsIn this study, the genes closely related to itaconic acid production, including cadA, mfsA, mttA, ATEG_09969, gpdA, ATEG_01954, acoA, mt-pfkA and citA, were identified and overexpressed in an industrial A. terreus strain respectively. Overexpression of the genes cadA (cis-aconitate decarboxylase) and mfsA (Major Facilitator Superfamily Transporter) enhanced the itaconate production level by 9.4% and 5.1% in shake flasks respectively. Overexpression of other genes showed varied effects on itaconate production. The titers of other organic acids were affected by the introduced genes to different extent.ConclusionsItaconic acid production could be improved through genetic engineering of the industrially used A. terreus strain. We have identified some important genes such as cadA and mfsA, whose overexpression led to the increased itaconate productivity, and successfully developed a strategy to establish a highly efficient microbial cell factory for itaconate protuction. Our results will provide a guide for further enhancement of the itaconic acid production level through genetic engineering in future.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-014-0119-y) contains supplementary material, which is available to authorized users.
Highlights
Itaconic acid, which has been declared to be one of the most promising and flexible building blocks, is currently used as monomer or co-monomer in the polymer industry, and produced commercially by Aspergillus terreus
The sequence identities between cloned mfsA, ATEG_09969, gpdA, acoA and the annotated ones are 80.5% to 93.2% and 81.5% to 92.8% at the gene and protein levels respectively
Since the functions of most annotated genes in the genome sequence of A. terreus NIH2624 were predicted only and have not been characterized yet, the big difference in coding sequences (CDSs) between the cloned and annotated genes is possibly caused by designation of introns or/and exons or/and translation start sites or/and stop codons
Summary
Itaconic acid, which has been declared to be one of the most promising and flexible building blocks, is currently used as monomer or co-monomer in the polymer industry, and produced commercially by Aspergillus terreus. Itaconic acid is on the DOE (Department of Energy) top 12 list of the biotechnologically produced key building blocks in chemicals production, and is a valuable monomer or co-monomer in polymers manufacturing [1,2]. In future, it can even replace methacylic acid which is presently produced by the petrochemical industry [3]. Pyruvate is either transported to the mitochondria and converted into acetyl-CoA, or carboxylated into oxaloacetate in the cytosol. Itaconic acid is exported out of the cell likely via the di-carboxylic acid carrier
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
