Agronomic and Environmental Performance of Lemnaminor Cultivated on Agricultural Wastewater Streams—A Practical Approach

Abstract

This study investigated the potential of Lemna minor to valorise agricultural wastewater in protein-rich feed material in order to meet the growing demand for animal feed protein and reduce the excess of nutrients in certain European regions. For this purpose, three pilot-scale systems were monitored for 175 days under outdoor conditions in Flanders. The systems were fed with the effluent of aquaculture (pikeperch production—PP), a mixture of diluted pig manure wastewater (PM), and a synthetic medium (SM). PM showed the highest productivity (6.1 ± 2.5 g DW m−2 d−1) and N uptake (327 ± 107 mg N m−2 d−1). PP yielded a similar productivity and both wastewaters resulted in higher productivities than SM. Furthermore, all media showed similar P uptake rates (65–70 P m−2 d−1). Finally, duckweed had a beneficial amino acid composition for humans (essential amino acid index = 1.1), broilers and pigs. This study also showed that the growing medium had more influence on the productivity of duckweed than on its amino acid composition or protein content, with the latter being only slightly affected by the different media studied. Overall, these results demonstrate that duckweed can effectively remove nutrients from agriculture wastewaters while producing quality protein.

On the rise: Development of a multi‐tiered, indoor duckweed cultivation system

“…As a result, duckweed species can be used to effectively remediate wastewater and recycle plant nutrients in accordance with the principles of the circular economy. Ample examples of duckweed‐based nutrient recycling have been published, and these relate to different nutrient‐rich wastewaters, such as farm manure (Dinh et al, 2020; Hu et al, 2019), aquaculture‐industry wastewater (Devlamynck et al, 2021; Paolacci et al, 2021), processing wastewater from the dairy industry (Walsh et al, 2020, 2021), and municipal wastewater (Kotoula et al, 2020). Nutrient recycling involves the use of nutritionally desirable duckweed biomass as feed and/or food for livestock and human consumption (Sree et al, 2015), fertilizer (Ahmad et al, 1990; Chikuvire et al, 2018) or biofuel (Chen et al, 2022).…”

Effect of dietary supplementation of duckweed on growth performance, carcass and non-carcass traits of horro rams fed on a commercial-based diet

“…Duckweed grown under ideal conditions contains 17.50%–37.00% total protein on a dry weight basis [ 15 ], 59.33% of total carbohydrates, and 7.33% of lipids [ 16 ]. Duckweed has a wider range of essential amino acids [ 17 ] and is rich in macro and micronutrients [ 16 ]. Studies showed that duckweed is one of the potential protein sources that can be easily produced by farmers, and used as supplementary feed to livestock [ 18 ].…”

Maximizing nutrient recycling from digestate for production of protein-rich microalgae for animal feed application

“…This situation calls for alternate management systems to valorize the surplus of waste residues. Therefore, the recycling of nutrients from digestate for production of feed-grade protein creates an opportunity for a circular nutrient economy concept (Devlamynck et al, 2021).…”