Wastewater from the demineralization of cheese whey for cost-efficient cultivation of spirulina

Worldwide, there is growing interest in achieving a meaningful use of natural resources, as epitomized in this work, which demonstrates the use of saline wastewater (WW) from the demineralization of cheese whey as the main component of a medium for cultivation of spirulina ( Limnospira maxima ). Based on Zarrouk medium and the fundamental composition of spirulina biomass, a novel cultivation medium for photoautotrophic cultivation of spirulina was developed. The wastewater medium (WWM) consisted of WW supplemented with NaHCO 3 , urea, K 2 HPO 4 , and FeSO 4 . The suitability of WWM was evaluated by comparison of spirulina growth in laboratory scale tubular or gas-lift photobioreactors in WWM and Zarrouk medium (ZM). The maximum biomass productivity of 0.36 g L −1 day −1 was achieved in WWM, compared with 0.24 g L −1 day −1 in ZM. The cost of WWM was less than 50% of the cost of ZM.