Introduction: The soil bacterium C. glutamicum is an industrial producer for a broad spectrum of added-value products [1]. Efforts in metabolic engineering of C. glutamicum over the past decades have greatly benefited from a detailed understanding of its cellular physiology, mainly using glucose and sucrose as raw materials [2] [3]. For a sustainable bio-economy, we need, however, more than glucose and sucrose. Spent sulfite liquor (SSL) is a potentially attractive waste stream of the forestry industry to be used by C. glutamicum for industrial bio-production. It is a crude mixture of different sugars and contains mannose as major ingredient.
Objectives: Naturally, C. glutamicum, grows very poor on mannose, hence, we need to overcome the bottleneck and understand the central metabolism with mannose as carbon source.
Materials & methods: Genetic engineering, 13C metabolic flux analysis and in silico pathway modelling using elementary flux modes.
Results: Here, we have created a mutant, which exhibits over expression of manA encoding mannose-6-phosphate isomerase for enhanced interconversion of mannose-6-phosphate and fructose-6-phosphate [4]. The genomic modification restored mannose-based growth and the intracellular flux distributions of the newly created metabolism on mannose were determined.
Conclusion: The data provide interesting insights into the physiology of the microbe and promise valuable knowledge for industrial use of SSL based raw materials.

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