Co-cultivation of Chlorella spp and tomato in a hydroponic system

In this study, a new cost-effective and environmentally sustainable microalgal production strategy was developed on the basis of the microalgae-crop symbiosis association. This method allowed the simultaneous production of microalgae and crops by using a simple eco-hydroponic system (EHS), with the input only for crop production. In glasshouse experiments, green algae Chlorella infusionum was successfully cultivated in a hydroponic culture system cultivating tomato. The algal and crop biomass productivities in the EHS were 32 ± 5 g m−3 d−1 and 54.24 ± 1.81 g dm−3 d−1 (n = 6 for each), respectively, which was significantly (P < 0.05) greater than the algal biomass productivity (16 ± 5 g m−3 d−1, n = 6) in the algal monoculture and the crop biomass productivity (33.97 ± 7.58 g dm−3 d−1, n = 6) in the crop monoculture without aeration. The enhancement of the biomass productions was mainly attributed to the aeration from algal photosynthesis and the CO2 fertilization from crop root respiration in the EHS. Particularly, the nitrogen and phosphorus utilization efficiencies were high due to co-utilization of the nutrients by microalgae and crop in the EHS. This simple system could thus be applied as a model system for microalgal farming and hydroponic crop production.