Our aim was to develop a novel medium for the large-scale production of protein-rich Arthrospira with potential applications as a biofertilizer. The novel culture medium, termed as FM-II, was formulated using low-cost commercial chemicals and specifically designed to improve protein production. Both Arthrospira platensis and Arthrospira maxima were produced using FM-II and Arnon medium, which was used as a control. Photosynthetic status of the cells, which was checked by measuring chlorophyll fluorescence, biomass dry weight and protein content, was assessed daily. Arthrospira platensis had higher biomass and protein productivities than A. maxima when cultured in both control and FM-II media. Incorporation of varied micronutrients into FM-II formulation did not improve biomass productivity. Maximum biomass dry weight in FM-II and control medium was 2.9 and 2.5 g · L−1, respectively. Total protein content of the biomass ranged between 55% and 65%, suggesting potential for being used in the development of high-value agricultural products. As some nutrients were discarded unused, the initial content of phosphates and bicarbonates was reduced by 75% and 50%, respectively, without affecting the process productivity. Results reported herein could promote the production and utilization of Arthrospira platensis by significantly reducing productions costs and therefore increasing the feasibility of the process
