Global cellular metabolic rewiring adapts Corynebacterium glutamicum to efficient non-natural substrate utilization

Efficient assimilation of renewable feedstocks is the cornerstone for achieving sustainable and economical microbial production of commodity chemicals. Unfortunately, most renewables are foreign to the cellular metabolism of classical industrial workhorses, resulting in unsatisfactory biomanufacturing performance. Here, Corynebacterium glutamicum was systematically engineered for rapid non-natural xylose metabolism and the underlying adaptations were elucidated by combining metabolic engineering, adaptive laboratory evolution and systems biology techniques. A plasmid-free, stable and efficient xylose-utilizing chassis strain, named CGS15, was reconstructed with both a rapid specific growth rate of 0.341 h-1 on xylose and an excellent co-utilization of glucose and xylose at a ratio of about 2:1. For the first time, we revealed a novel xylose regulatory mechanism by the endogenous transcription factor IpsA with global regulatory effects on C. glutamicum core carbon and energy metabolism. The coordination between the heterologous xylose metabolism and the endogenous carbon/energy metabolism both endowed cells with accelerated growth and released carbon catabolite repression. Finally, this chassis demonstrated great promise for lignocellulosic biorefinery applications by producing 97.1 g/L of the platform compound succinate from corn stalk hydrolysate with an average productivity of 8.09 g/L/h. This work provides an elegant paradigm to understand and engineer the metabolism of renewable substrates for sustainable biomanufacturing. Here, we applied integrated multidisciplinary strategies including metabolic engineering, evolutionary engineering and systems biology to systematically investigate rapid non-natural substrate (xylose) metabolism in Corynebacterium glutamicum.