Original Research ArticleEstablishing a synergetic carbon utilization mechanism for non-catabolic use of glucose in microbial synthesis of trehalose

- A synergetic carbon utilization mechanism (SynCar) is designed.
- A glucose-based trehalose biosynthesis model is constructed for demonstration.
- The enhancement on trehalose titer (131%) and yield (200%) is achieved.
- The highest titer of trehalose in shake flasks is 8.2 g/L.

In nature glucose is a common carbon and energy source for catabolic use and also a building unit of polysaccharides and glycosylated compounds. The presence of strong glucose catabolic pathways in microorganism rapidly decomposes glucose into smaller metabolites and challenges non-catabolic utilization of glucose as C6 building unit or precursor. To address this dilemma, we design a synergetic carbon utilization mechanism (SynCar), in which glucose catabolism is inactivated and a second carbon source (e.g. glycerol) is employed to maintain cell growth and rationally strengthen PEP driving force for glucose uptake and non-catabolic utilization. Remarkably, a trehalose biosynthesis model developed for proof-of-concept indicates that SynCar leads to 131% and 200% improvement in trehalose titer and yield, respectively. The conversion rate of glucose to trehalose reaches 91% of the theoretical maximum. This work demonstrates the broad applicability of SynCar in the biosynthesis of molecules derived from non-catabolic glucose.