Regulation of species metabolism in synthetic community systems by environmental pH oscillations

Abstract

Constructing a synthetic community system helps scientist understand the complex interactions among species in a community and its environment. Herein, a two-species community is constructed with species A (artificial cells encapsulating pH-responsive molecules and sucrose) and species B (Saccharomyces cerevisiae), which causes the environment to exhibit pH oscillation behaviour due to the generation and dissipation of CO₂. In addition, a three-species community is constructed with species A′ (artificial cells containing sucrose and G6P), species B, and species C (artificial cells containing NAD⁺ and G6PDH). The solution pH oscillation regulates the periodical release of G6P from species A′; G6P then enters species C to promote the metabolic reaction that converts NAD⁺ to NADH. The location of species A′ and B determines the metabolism behaviour in species C in the spatially coded three-species communities with CA′B, CBA′, and A′CB patterns. The proposed synthetic community system provides a foundation to construct a more complicated microecosystem.

Most synthetic communities are unidirectional or two-way interaction without dynamic feedback. Here, the authors report a dynamic feedback system involving artificial cell species, biological cell species, and their environment using pH-sensitive molecule that phase-shift between fluid and gel phases.