Influence of technological parameters on the growth of continuous spirulina (Arthrospira platensis) culture in open channels

Abstract

Spirulina cultivation is a significant activity due to its high nutritional value, including proteins, vitamins, minerals, and antioxidants. This study evaluates the influence of technological parameters on the growth and productivity of continuous Arthrospira platensis cultivation in open channels. The impact of temperature, flow velocity, and light intensity on biomass and nutritional values was analyzed. A fractional factorial 2k-1 experiment was designed with four treatments and three replicates under a semi-controlled environment. Inferential statistical analysis (ANOVA and multiple regression) showed that temperature is the most critical factor in biomass production (F=4147.36, p=0.000), protein content (F=70.43, p=0.000), and minerals such as magnesium, phosphorus, potassium, calcium, and iron. An increase in temperature from 18°C to 28°C led to a rise in biomass from 0.65 g/L to 0.85 g/L and enhanced protein concentration. Flow velocity also had a significant positive impact on biomass (F=1324.96, p=0.000), improving culture homogeneity and nutrient absorption when increased from 0.15 to 0.30 m/s. Meanwhile, light intensity had a negative effect at levels above 20,000 lux, reducing biomass and protein quality. Optimizing temperature and flow velocity is key to maximizing biomass and nutritional quality in open-system spirulina cultivation, while light intensity must be controlled to prevent adverse effects. The results support the development of more efficient and sustainable production systems aligned with industrial demand.