Duckweed as a Sustainable Protein Source for EU Animal Feed

Duckweed (Lemnaceae) is a high-protein, fast-growing aquatic plant with potential as a sustainable feed and food source in the EU. In 2013, 63% of the EU’s protein-rich feed was imported, driving demand for alternatives. Duckweed yields up to 180 ton dry weight per hectare annually under optimal conditions, with 10–55 ton DW ha⁻¹ y⁻¹ in field settings. It contains 15–45% protein and favorable amino acid profiles. Laboratory studies selected salt-tolerant clones, including Uddel, for resilience in agricultural wastewater. A pilot-scale lagoon using aquacultural effluent produced 2.2 kg DW over 12 months (5.1 ton DW ha⁻¹ y⁻¹), with 28% protein content (1.4 ton protein ha⁻¹ y⁻¹). Nitrogen and phosphorus uptake averaged 5.5 g N and 1.4 g P per day. Growth peaked in July (doubling time: 7.6 days), declining in spring and autumn, and ceasing in winter. The Uddel clone showed best performance in aquaculture effluent. A full mass balance is planned to assess phytoremediation potential. Research is funded by Interreg V Blauwe Keten, with support from EFRD.