The Biotechnological Potential of Corynebacterium glutamicum, from Umami to Chemurgy

Abstract

Corynebacterium glutamicum exhibits numerous ideal intrinsic attributes as a microbial factory to produce not only amino acids but also chemicals. The large range of products that can now be biomanufactured mediates a transformational change in the deployment of this microorganism, from umami applications, referring to food enhancers, to chemurgy applications, referring to chemical commodity products. The deep fundamental knowledge of the corynebacterial physiology, the experience curve gained by manufacturing for decades at the industrial scale numerous amino acids, and postgenomic tools to model processes or design synthetic pathways in combinatorial approaches constitute a foundational basis to design efficient and versatile corynebacterial biorefineries. Moreover, the detailed knowledge in amino acid biosynthetic routes can be leveraged to harness the chemical space around these molecules, as exemplified by producing isobutanol from an engineered valine pathway; biosynthesis and chemical synthesis can also be coupled to produce sustainable intermediates. A wide range of applications can nowadays be addressed using C. glutamicum owing to its intrinsic safety and process performance, including also industrial enzymes, therapeutic proteins, antibody fragments, and secondary metabolites comprising small molecule natural products. The economics of the corynebacterial biorefinery could further be enhanced by valorizing its effluents in innovative ways, such as the use of the spent biomass in bioremediation or mining. A critical success factor is to compute an economically optimized process/product mix to create an interconnected product line for serving various markets offering attractive profit margins, covering not only the food and chemical industry but also the cosmetics and pharmaceutical ones.