Chemical Garden Catalysis of Prebiotic Chemistry

Prebiotic processes required a reliable source of free energy and complex chemical mixtures that likely included sugars. The formose reaction is a potential source of those sugars but is tied to alkaline conditions and elevated temperatures, under which these sugars rapidly decay. Here we show that calcium, barium and iron based chemical gardens catalyze the formose reaction to produce glucose, ribose, and other carbohydrates. These thin inorganic membranes are analogs of hydrothermal vent materials—a possible place for the origin of life—and similarly exposed to very steep pH gradients. Supported by simulations of a simple reaction-diffusion model, we show that such gradients allow for the dynamic accumulation of sugars in specific layers of the thin membrane. This spatial separation of sugar production and accumulation might have been one of the earliest examples of pre-biological compartmentalization.