Agricultural fertilizer-enhanced medium for scalable cultivation of Euglena sp. to boost growth and lipid yield

Euglena gracilis offers significant potential as a functional food source, but the high cost of nutrients is an obstacle to its large-scale application. The research aims to explore the use of agricultural fertilizer-modified media (AgFME) as a nitrogen substrate for the cultivation of Euglena sp. Specifically, we assessed two modified media, AgFME1 (NH4SO4) and AgFME2 (Ca(NO3)2), in comparison with the traditional Cramer-Mayer medium (CM). Key parameters such as cell density, biomass, pigment content, protein, and lipid production were evaluated to determine the feasibility of cost-effective Euglena sp. cultivation. Results showed a significant increase in cell density (p < 0.05) for AgFME treatments, with no substantial differences in specific growth rate, doubling time, or biomass (p > 0.05). Carotenoid and chlorophyll-a levels were lower in AgFME2 compared to CM. However, lipid production was significantly higher in both AgFME1 and AgFME2 media. Fatty acid analysis revealed a greater accumulation of saturated fatty acids in AgFME treatments, with AgFME2 showing the highest lipid and eicosapentaenoic acid (EPA) content. In contrast, polyunsaturated fatty acids were most abundant in the CM medium. Our findings demonstrate that agricultural fertilizer-modified media can provide a cost-effective alternative to traditional media for cultivating Euglena sp. with potential for enhanced lipid and fatty acid production. AgFME2 may be particularly promising for producing EPA, a key component for functional foods and nutraceuticals.