Harvesting of Spirulina platensis using an eco-friendly fungal bioflocculant produced from agro-industrial by-products.

This study aimed to produce fungal biomass from agro-industrial by-products for later use as a bioflocculant in the Spirulina harvesting. The production of fungal biomass from Aspergillus niger was carried out in submerged fermentation, using media composed of wheat bran and/or potato peel. Fungal biomass was used as a bioflocculant in Spirulina cultures carried out in closed 5 L reactors and 180 L open raceway pond operated in batch and semi-continuous processes, respectively. Fungal biomass was able to harvest Spirulina platensis cultures with efficiencies between 90% and 100% after 2 h of sedimentation in some experimental conditions. Efficiencies higher than 80% were achieved in most tests without pH adjustment during bioflocculations, which shows that the developed method is a promising alternative to traditional Spirulina harvesting techniques. Above all, the development of an eco-friendly fungal-assisted bioflocculation process increases the sustainability of Spirulina biomass for different applications, especially biofuels.