Maximizing nutrient recycling from digestate for production of protein-rich microalgae for animal feed application
Seelam, J.S.; Fernandes de Souza, M.; Chaerle, P.; Willems, B.; Michels, E.; Vyverman, W.; Meers, E. (2022). Maximizing nutrient recycling from digestate for production of protein-rich microalgae for animal feed application. Chemosphere 290: 133180. https://dx.doi.org/10.1016/j.chemosphere.2021.133180
In: Chemosphere. Elsevier: Oxford. ISSN 0045-6535; e-ISSN 1879-1298, more
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Digestate; Microalgae; Microplate experiments; Paper-filtration; Photobioreactor |
| Authors | | Top |
- Seelam, J.S.
- Fernandes de Souza, M.
- Chaerle, P., more
- Willems, B.
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- Michels, E.
- Vyverman, W., more
- Meers, E., more
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| Abstract |
The integration of phototrophic microalgal production and anaerobic digestion can recycle excess nutrients across European surplus hotspots to produce protein-rich biomass for nutritional applications. However, the challenging physico-chemical properties of raw digestate constrain microalgal growth and limit digestate valorization potential. This study focused on the pre-treatment of food waste-based digestate using paper-filtration to improve its properties for cultivating Desmodesmus sp. and Chlorella vulgaris. The microalgal growth performance in paper-filtered digestate (PFD, 10 μm-pore size) was then compared to growth in membrane-filtered digestate (MFD, 0.2 μm-pore size). A microplate-based screening coupled with Cytation device assessment of PFD and MFD samples after dilution and with/without phosphorus supplementation showed that PFD was the best substrate. Moreover, phosphorus supplementation resulted in improved growth at higher digestate concentrations (5–10% v/v PFD), indicating the importance of using a balanced growth medium to increase the volumetric usage of digestate. Results were validated in a 3-L bioreactor at 10% PFD with phosphorus supplementation, reaching a biomass concentration of 2.4 g L−1 with a protein and carbohydrate content of 67% and 13% w/w respectively. This trial indicates that paper-filtration is a promising pre-treatment technique to maximize digestate recycling and deliver a sustainable animal feed-grade protein alternative. |
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