Sustainable cultivation of microalgae Euglena sp. IDN 22 using anaerobic digested manure wastewater: Integrating circular bioeconomy principles in agroindustry

This research was conducted by utilizing anaerobic digested manure wastewater (ADMW) as a growth medium for microalgae Euglena sp. IDN 22. This research aimed to determine the effectiveness of using ADMW as a rich nutrient supplement to cultivate microalgae Euglena sp. IDN 22. Multiple dilutions of 0, 25, 50, and 75 were applied to ADMW, and the growth of Euglena sp. IDN 22 was analyzed using the growth rate of microalgae cell counts. The number of cells was observed with a haemocytometer. The cultivation of Euglena sp. IDN 22 in the ADMW medium was conducted in lab-scale (1 L) photobioreactors for 15 days of cultivation. The analysis of 25 ADMW showed C/N and P/N of 7.40 ± 0.17 and 1.27± 0.03, while 50 ADMW analysis yielded 14.99 ± 0.51 and 1.72 ± 0.07. The best growth rate trend of Euglena sp. IDN 22 in ADMW was shown by the treatment with 25 ADMW dilution with a maximum growth of 62.92 × 104 cells/ml, compared to a maximum growth of 79.92 × 104 cells/ml with 0 ADMW as a control. Slow growth activity was shown by 50 and 75 ADMW, with a maximum growth of only 10.67 × 104 cells/ml and 4.45 × 104 cells/ml, respectively. The slow growth activity in 50 ADMW, with a maximum growth of only 10.67 × 104 cells/ml, demonstrated a significant difference (p?> 0.01). The results of this study prove that the integration of 25 ADMW and Euglena sp. IDN 22 cultivation can be an effective valorization concept and an opportunity to transform biogas production waste towards a circular economy in agroindustry. © (2025), (Polish Society of Ecological Engineering (PTIE)). All Rights Reserved.