Development and Performance Evaluation of a Household Photobioreactor for Arthrospira (Spirulina) platensis Cultivation

Arthrospira (Spirulina) platensis is a filamentous cyanobacterium efficiently cultivated for its high nutritional and functional value, being rich in protein, phycocyanin, essential fatty acids, and vitamins. Cultivation at the household level provides fresh biomass and improves access to nutritious food sources. This study aimed to develop a prototype bioreactor for small-scale Arthrospira cultivation as a simple and sustainable production model. The developed system comprised a 10-liter culture vessel equipped with integrated aeration and illumination units to ensure efficient mixing and uniform light distribution. The culture was operated in a semi-continuous mode under ambient, non-controlled temperature conditions, involving daily harvesting and replenishment with fresh medium to maintain a cell concentration corresponding to an optical density (OD) of 0.4 at 560 nm. Continuous illumination (24 h per day) was provided by daylight LED lamps delivering a photosynthetic photon flux density (PPFD) of 480 µmol m⁻² s⁻¹, with a total power consumption of 36 watts. Under these conditions, the prototype achieved a biomass productivity of 0.12 g L⁻¹ day⁻¹, corresponding to a biomass yield of 1.34 g day⁻¹ at a dilution rate of 0.34 day⁻¹ and an energy consumption of 0.645 kWh per gram of biomass produced (equivalent to an energy efficiency of 1.55 g biomass per kWh), demonstrating the technical feasibility of small-scale Arthrospira production. Future work will focus on optimizing operational parameters, particularly lighting efficiency, to enhance productivity and promote sustainable household cultivation.