Engineering algal-yeast consortia to accelerate biocrust formation through metabolic complementarity and mineral stabilization.

Abstract

Biological soil crusts (BSCs) are key biotic interfaces for soil stabilization, nutrient cycling, and ecosystem recovery in arid and semi-arid landscapes, yet the mechanisms by which algal-yeast consortia accelerate early crust formation remain insufficiently resolved. Here, we evaluated the effects of co-inoculating Chlorella vulgaris and Saccharomyces cerevisiae on BSC development using Fourier transform infrared spectroscopy, contact angle analysis, chlorophyll quantification, soil physicochemical measurements, aggregate stability assessment, and density functional theory (DFT) calculations. Compared with the loess control, co-inoculation markedly promoted crust development, increasing total dissolved solids by approximately 15-fold, extending water retention time by threefold, increasing macroaggregate formation by 3.8-fold (90 day), and raising the surface contact angle from 0° to 88.9°. These responses indicate a transition from a highly hydrophilic loose loess surface toward an organically coated, structurally consolidated crust. DFT calculations further showed stronger modeled adsorption of algal-derived β-D-glucopyranose on SiO2 than yeast-derived β-D-mannose disaccharide, supporting a possible anchoring-filling mechanism within the extracellular polymeric substance (EPS) network. Together, the results suggest that yeast contributes to nutrient transformation and organic matter input, whereas algal and yeast EPS jointly reinforce mineral binding, aggregate stabilization, and water retention. This study links molecular scale EPS-mineral interactions with macroscopic soil structural development and provides a mechanistic basis for designing algal-yeast inoculants for dryland restoration.

Abstract as supplied by the indexing source. © the authors / publisher.