Sustainable microalgal biomass production toward circular economy: wastewater treatment and potential bioproducts

REARTE T.A.

Ciudad Autónoma de Buenos Aires

Simposio; 2022 FEWSUS ANNUAL SYMPOSIUM. BIOECONOMY SYSTEMS FOR URBAN-RURAL CO-PROSPERITY; 2022

In recent years, special interest has been given to research and development of microalgae biotechnology due to key advantages: high growth and nutrient uptake rates, broad taxonomic and metabolic diversity, carbon fixation, no fertile land requirement, wastewater treatment, and special emphasis on the integrated conversion of biomass into food, energy, chemical compounds, and new materials. In this context, microalgal biomass emerges as a high potential feedstock within the new concept of circular bioeconomy, because it is a renewable source of a wide range of bioproducts that can be produced using wastewaters and flue gases. There are around 45,000 descripted species of microalgae and only a few species are massively cultivated for environmental and commercial purposes. Therefore, investigating the diversity of organisms under culture conditions is a key step in the search for species with biotechnological potential. Filamentous microalgae present few studies on the subject because most of the methods of microalgae culture methods have been developed for unicellular species of easy isolation and culture at massive scale. Despite the high productive potential of microalgae, its implementation at commercial scale is still limited due to the high production costs. The higher costs are associated with harvesting processes and the provision of nutrients (fertilizers and carbon dioxide). Our projects aim to overcome these tecno-economic barriers, since filamentous microalgae species facilitate drastically the harvesting process and the utilization of wastewaters for nutrient recovery and biomass production. The performance of a pilot plant of wastewater treatment with unicellular and filamentous microalgae under different climatic conditions and operating regimes are being evaluated. By recovering the nutrients, the microalgal biomass has a high potential to be applied in agriculture as biofertilizers or biostimulants of plant growth. Studies are being developed from different disciplinary approaches: culture biology and metabolism, photobiological and photosynthetic approaches, modeling, and process bioengineering. Regarding the application of biomass, bioestimulants, biofertilizers, carotenoid, and polyunsaturated fatty acids are studied with the objective of technology transference to the interested actors.