Gluconeogenesis in Aqueous Microdroplets: Non-Enzymatic Generation of Glucose

Abstract

Glucose is a central metabolite of living organisms, serving as the primary energy substrate produced predominantly by photosynthetic organisms. Under conditions of limited external glucose supply, organisms activate gluconeogenesis, an endogenous biosynthetic pathway that sustains essential glucose levels. Yet the mechanism of glucose generation, before the advent of photosynthesis and complex enzymatic systems, remains elusive. Recently, microdroplet chemistry has emerged as a novel approach for catalyst-free organic synthesis. Here, we report the non-enzymatic formation of glucose from a simpler organic precursor, pyruvate, in aqueous microdroplets without the aid of organic or inorganic catalysts. Our results show that glucose is generated via a reaction pathway analogous to canonical gluconeogenesis, proceeding through key intermediates including oxaloacetate, glycerate, and glyceraldehyde. Furthermore, thermodynamic analysis indicates that the free energy change associated with glucose formation is overcome in aqueous microdroplets at room temperature, without the need for external energy input or enzymatic catalysis. These findings indicate that aqueous microdroplets can non-enzymatically convert C3 compound, pyruvate, into the C6 sugar glucose, offering a plausible abiotic route for anabolic carbon transformations during abiogenesis.