Dilution rate caused nutrient limitation effects on the biomass composition and proteomic level of continuously cultivated Spirulina in recirculating aquaculture system wastewater
Year: 2024
Type: article
Abstract: Recirculating aquaculture system (RAS) wastewater from Nile tilapia cultivation can negatively impact aquatic ecosystems. Continuous cultivation provides a steady state for Spirulina growth and nutrient removal. This study investigated the optimal dilution rate of the RAS wastewater to maximize biomass production and nutrient removal in continuous Spirulina cultivation. Moreover, changes in the biomass composition and proteome under nutrient–limiting conditions were investigated. Continuous cultivation was performed at four different dilution rates of 0.20, 0.25, 0.35, and 0.50 d–1 using two different culture mediums, RASN50 and RASN80, which were prepared from raw RAS wastewater containing nitrate concentrations of 50 mg N/L and 80 mg N/L, respectively. The optimal dilution rates for RASN50 and RASN80 were 0.35 d–1 and 0.20 d–1, respectively. Under these conditions, Spirulina could maintain high removal efficiencies of over 80% for nitrate and over 99% for phosphate while achieving effective biomass productivities ranging from 0.18–0.22 g DW/L/d. However, the cultivation using RASN50 at a dilution rate of 0.20 d–1 led to nutrient–limiting conditions. Under this condition, the protein content in biomass decreases due to the phycocyanin degradation. Moreover, Spirulina increased glucose synthesis from carbon fixation and gluconeogenesis, resulting in an increased carbohydrate content in its biomass.
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,420
Award: G6060719267
OpenAlex ID: W4405224405