초록
<P>In the present work, we established the bio-based production of glutarate, a carbon-5 dicarboxylic acid with recognized value for commercial plastics and other applications, using metabolically engineered <I>Corynebacterium glutamicum</I>. The mutant <I>C. glutamicum</I> AVA-2 served as a starting point for strain development, because it secreted small amounts of glutarate as a consequence of its engineered 5-aminovalerate pathway. Starting from AVA-2, we overexpressed 5-aminovalerate transaminase (<I>gabT</I>) and glutarate semialdehyde dehydrogenase (<I>gabD</I>) under the control of the constitutive <I>tuf</I> promoter to convert 5-aminovalerate further to glutarate. The created strain GTA-1 formed glutarate as a major product, but still secreted 5-aminovalerate as well. This bottleneck was tackled at the level of 5-aminovalerate re-import. The advanced strain GTA-4 overexpressed the newly discovered 5-aminovalerate importer NCgl0464 and formed glutarate from glucose in a yield of 0.27 mol mol<SUP>−1</SUP>. In a fed-batch process, GTA-4 produced more than 90 g L<SUP>−1</SUP> glutarate from glucose and molasses based sugars in a yield of up to 0.70 mol mol<SUP>−1</SUP> and a maximum productivity of 1.8 g L<SUP>−1</SUP> h<SUP>−1</SUP>, while 5-aminovalerate was no longer secreted. The bio-based glutaric acid was purified to >99.9% purity. Interfacial polymerization and melt polymerization with hexamethylenediamine yielded bionylon-6,5, a polyamide with a unique structure.</P><P>Graphic Abstract</P><P>Here, we present a green route to glutaric acid, a chemical of recognized industrial value, using a tailor-made cell factory.<BR/><IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c8gc01901k'/><BR/></P>