Biodegradable, metal-chelating compounds as alternatives to EDTA for cultivation of marine microalgae

• DOI: 10.1007/s10811-021-02583-0
• Publication Date: 2021-09-16T15:02:53Z
• Authors: Justine Sauvage; Gary H. Wikfors; Koen Sabbe; Nancy Nevejan; Steven Goderis; Philippe Claeys; Xiaoxu Li; Alyssa Joyce
• Keywords: Nannochloropsis; Photobioreactor; Ethylenediaminetetraacetic acid; Alginic acid

Abstract Iron (Fe) is an essential nutrient for microalgal metabolism. The low solubility of Fe in oxic aquatic environments can be a growth-limiting factor phytoplankton. Synthetic chelating agents, such as ethylenediaminetetraacetic acid (EDTA), are used widely to maintain solution cultivation. non-biodegradable nature EDTA, combined with sub-optimal bioavailability Fe-EDTA complexes microalgae, indicates opportunity improve cultivation practices that amplify production efficiency and environmental compatibility. In the present study, effects four organic ligands known form readily bioavailable natural were investigated relation growth biochemical composition two marine microalgae grown live feeds shellfish hatcheries ( Chaetoceros calcitrans Tisochrysis lutea ). Three saccharides, alginic (ALG), glucuronic (GLU), dextran (DEX), well siderophore desferrioxamine B (DFB), compared EDTA. Organic characterized by weaker binding capacity cationic metals (i.e., ALG, GLU, DEX) significantly improved yields laboratory-scale static batch cultures or bubbled photobioreactors. Maximal enhancement relative control (e.g., EDTA) was recorded followed 20–35% increase specific rate early stages culture development C. T. . Substitution EDTA GLU resulted 27% cellular omega 3-polyunsaturetd fatty content doubled final cell yields. Enhanced performance likely associated increased intracellular uptake heterotrophic stimulated ligands. Based upon these results, we propose replacement one metal-chelating effective easily implementable strategy enhance compatibility while also maximizing algal enhancing nutritional quality species commonly cultured live-feed applications aquaculture.