Use of Spirulina biomass produced from treatment of aquaculture wastewater as agricultural fertilizers

Microalgal research has been an area of great interest as microalgae have higher productivities than land plants and can be used for the production of valuable commodities such as biofuel, animal feeds and agricultural fertilizers, among others. To enhance the economic feasibility of algal-based commodities, the growth of microalgae can be coupled to wastewater remediation. The technical feasibility of cultivating Spirulina platensis with fish water for production of algae fertilizers was investigated. The remediation potential of S. platensis was found to be good for ammonia and nitrate removal, but inadequate for nitrite removal. Its specific growth rate of 0.026 h− 1 and the nutrient reduction times compare well with various literature reports. This work provides insight into the potential of algal biomass as agricultural fertilizers, when coupled with aquaculture wastewater remediation. The ability of Spirulina-based fertilizers to enhance plant growth was demonstrated in leafy vegetables such as Arugula (Eruca sativa), Bayam Red (Ameranthus gangeticus) and Pak Choy (Brassica rapa ssp. chinensis). The germination of Chinese Cabbage (B. rapa ssp. chinensis) and Kai Lan (Brassica oleracea alboglabra) also improved significantly in terms of seedlings' dry weight.