Anaerobic digestate abattoir effluent (ADAE), a suitable source of nutrients for Arthrospira platensis cultivation

Untreated as well as partially treated anaerobic digestate abattoir effluent (ADAE) were used for the cultivation of Arthrospira platensis in this study. The effect of CO2 addition on the biomass productivity, nutrient removal efficiency and biochemical composition were also investigated. Arthrospira platensis exhibited significant improved growth in raw ADAE when alkalinity of the medium was adjusted to 6.3 g L-1 using NaHCO3. Addition of CO2 resulted in 20% increase in biomass productivity and higher ammoniacal nitrogen removal rate (99.0%) when compared to the cultures with no CO2 supplementation. No significant differences were found in protein (50.2%) and phycocyanin (12.0%) content of A. platensis cultivated in raw ADAE supplemented with HCO3 and that grown in synthetic Zarrouk medium. This study demonstrated that raw ADAE can be successfully used as culture media for A. platensis when its alkalinity is adjusted using bicarbonate. Such an approach would reduce the need of freshwater and external synthetic nutrients for A. platensis cultivation if the aim is to produce reclaimable water as well as biomass rich in protein content and phycocyanin for potential use as an animal and aquaculture feed.

Automated summary

The study showed that untreated ADAE can be successfully used as a culture medium for A. platensis with improved growth when alkalinity is adjusted. Adding CO2 resulted in increased biomass productivity and higher ammoniacal nitrogen removal rate.