TY  - JOUR
A1  - Pöschel, Laura
A1  - Gehr, Elisabeth
A1  - Buchhaupt, Markus
T1  - Improvement of dicarboxylic acid production with Methylorubrum extorquens by reduction of product reuptake
T2  - Applied microbiology and biotechnology
N2  - The methylotrophic bacterium Methylorubrum extorquens AM1 has the potential to become a platform organism for methanol-driven biotechnology. Its ethylmalonyl-CoA pathway (EMCP) is essential during growth on C1 compounds and harbors several CoA-activated dicarboxylic acids. Those acids could serve as precursor molecules for various polymers. In the past, two dicarboxylic acid products, namely mesaconic acid and 2-methylsuccinic acid, were successfully produced with heterologous thioesterase YciA from Escherichia coli, but the yield was reduced by product reuptake. In our study, we conducted extensive research on the uptake mechanism of those dicarboxylic acid products. By using 2,2-difluorosuccinic acid as a selection agent, we isolated a dicarboxylic acid import mutant. Analysis of the genome of this strain revealed a deletion in gene dctA2, which probably encodes an acid transporter. By testing additional single, double, and triple deletions, we were able to rule out the involvement of the two other DctA transporter homologs and the ketoglutarate transporter KgtP. Uptake of 2-methylsuccinic acid was significantly reduced in dctA2 mutants, while the uptake of mesaconic acid was completely prevented. Moreover, we demonstrated M. extorquens-based synthesis of citramalic acid and a further 1.4-fold increase in product yield using a transport-deficient strain. This work represents an important step towards the development of robust M. extorquens AM1 production strains for dicarboxylic acids.
KW  - Dicarboxylic acids
KW  - Methylorubrum extorquens
KW  - Product reuptake
KW  - Acid transporters
KW  - Ethylmalonyl-CoA
KW  - pathway
KW  - Methylotroph
Y1  - 2022
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/79553
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-795533
SN  - 1432-0614
VL  - 106
IS  - 19
SP  - 6713
EP  - 6731
PB  - Springer
CY  - Berlin ; Heidelberg ; New York
ER  -