Hydroponic Systems: Exploring the Balance Between Co-Cultivation of Chlorella Vulgaris and Swiss Chard (beta Vulgaris L. Subsp. Cicla)

Co-cultivation of plants and microalgae represents an optimized production method which is less resource intense and it is ecologically correct and clean. Hydroponically grown plants may have higher yields and better quality. The possibility of Swiss chard and Chlorella vulgaris co-cultivation and their joint impact on microalgae growth parameters such as optical and cell culture density, dry weight, biomass productivity, and pigment content were investigated. Swiss chard growth parameters (plant length, fresh and dry weight, root volume, and leaves number) were monitored and measured. Hydroponic medium used in the experiment was analyzed to estimate C. vulgaris effect on its quality parameters (chemical oxygen demand, pH, electrical conductivity, and total nutrients consumption). Nutrient removal efficiency was calculated, as well. This study proved simultaneously nutrient removal efficiency, extracellular production, and positive effect on plant growth. In Hoagland’s solution, co-culture, and monoculture, total nitrogen and phosphorus removal efficiency ranged from 92.41 to 97.48% and 96.41 to 99.96%, respectively. Monoculture C. vulgaris showed better growth and higher pigment (chlorophyll a, b and carotenoids) content. Furthermore, microalgae C. vulgaris did not interfere with Swiss chard development. Higher leaves number (18.56%), total fresh weight (17.13%), and root volume (36.98%) have proven the advantage of coupled cultivation rather than usage of Hoagland’s growth medium alone. Results demonstrated practicability of C. vulgaris–Swiss chard co-cultivation and its potential applicability, all in order to provide more sustainable and economically viable large-scale plant production in future.