Enhancing Nutritional Value and Sensory Quality of Spirulina (Arthrospira platensis) Through Preharvest Co-Cultivation with Yeast Saccharomyces cerevisiae

Spirulina’s (Arthrospira platensis) use in food applications is limited by its dark color and sulfurous odor. This study aimed to develop a preharvest bioprocessing strategy using Saccharomyces cerevisiae co-cultivation to address these limitations. At a yeast/microalgae biomass ratio of 10:1000 with 5 g/L of glucose supplementation, co-cultivation for 24 h induced a rapid color transition from dark blue–green to light green and imparted “floral–fruity” aromas. Major bioactive compounds, including β-carotene, linoleic acid, and γ-linolenic acid, increased significantly, while volatile sulfur compounds were eliminated. Chlorophyll a and carotenoid contents rose by over two fold, reflecting enhanced photosynthetic efficiency. Mechanistic analyses revealed that yeast-derived acetic acid upregulated genes involved in flavor precursor biosynthesis and promoted biomass accumulation. This strategy integrates sensory improvement with nutritional enhancement, providing a sustainable approach for developing spirulina-based functional foods.