Exploring the carbon skeleton cycling regulation mechanism of single-wavelength light quality promoting the accumulation of polysaccharides in Spirulina platensis FACHB-439: Based on transcriptomics

Carbon dioxide can be converted into carbohydrates by Spirulina to promote carbon neutrality and produce high added value bio-functional compounds (e.g. polysaccharides). This study explored the effects of different single-wavelength light qualities on Spirulina polysaccharides and the differences in gene expression. The experiment results indicated that red light could significantly increase the content of polysaccharides in Spirulina (116.88 mg/g), followed by blue light (99.83 mg/g), green light (95.23 mg/g), yellow light (50.50 mg/g), while the white light control group was 69.59 mg/g. Transcription analysis results revealed that red light adjusted the intracellular carbon skeleton cycling between glycolysis/gluconeogenesis pathway, pyruvate and amino acid metabolism, and protein synthesis, ultimately promoting the accumulation of carbon sources towards polysaccharide synthesis. These findings offer theoretical basis and data support for the promising carbon fixation and reutilization based on blue-green algae.