Cultivation of Spirulina platensis for biomass production and nutrient removal from synthetic human urine

Microalgae have long been recognized as having the potential to provide a better source of biofuel. In this study, Spirulina platensis was cultivated in human urine to couple wastewater treatment with biomass production. The characteristics of microalgae growth under autotrophic and mixotrophic (adding glucose or sodium acetate to the urine) conditions, wastewater nutrient removal and biomass quality were examined. After 7 days, 97% of NH 4 + -N , 96.5% of total phosphorus (TP) and 85–98% of urea in the urine (ca. 120-diluted) were removed by the microalgae under autotrophic culture (30 °C). The addition of organic carbon was found to greatly stimulate the microalgae growth. More important, the mixotrophic grown biomass showed an increase in the content of protein, which could be converted into biocrude oil via hydrothermal liquefaction. This study suggested that it might be possible to replace a common culture medium with human urine to produce S. platensis.