Enhanced Paramylon Production in Euglena gracilis through CRISPR/Cas9 and Its Antiaging Effects

Euglena gracilis is a photosynthetic microalga that can synthesize paramylon. This study utilized CRISPR/Cas9 to knock out β-1,3-glucan phosphorylase, resulting in engineered strains to increase paramylon production. The ldp1 mutant strain produced paramylon constituting 68.20% of the cellular dry weight and a yield of 1.49 g/L. Replacing the carbon source in AF-6 medium with glucose resulted in an increase in the paramylon content to 72.92% of the dry cell weight and a yield of 1.51 g/L. The observation of a single distinct peak in the light scattering spectrum suggests a high degree of purity (approaching 100%). Paramylon significantly reduces reactive oxygen species in Caenorhabditis elegans, enhances antioxidant enzyme activity, and improves resistance to oxidative stress and high temperatures. It also reduces DNA damage and extends the lifespan. The antiaging effects of paramylon may be mediated through the regulation of the insulin/insulin-like growth factor signaling pathway. In C. elegans (myo-3:GFP(mit)), paramylon treatment increased mitochondrial signaling (p < 0.01), ATP production, membrane potential, and the expression of longevity-related genes, suggesting enhanced mitochondrial function. This research not only optimizes paramylon production but also highlights its potential as an antioxidative and antiaging agent.