SCREENING OF ALGAL AND CYANOBACTERIAL STRAINS FOR OPTIMAL BIOMASS PRODUCTION AND NUTRIENT RECOVERY FROM DAIRY MANURE-BASED ANAEROBIC DIGESTION EFFLUENT

This research screened 4 cyanobacteria strains and 16 algae strains, including both isolated environmental species and strains purchased from the Culture Collection of Algae at the University of Texas at Austin (UTEX), for their ability to grow on anaerobic digestion effluent (ADE). The 4 most robust strains, based on growth rates and biomass production, were more closely investigated for their capacity to extract nitrogen (N) and phosphorus (P) from deionized water supplemented with 1, 5, and 10% ADE. According to the results, the decrease in concentration of total nitrogen (TN) varied between the strains examined. The greatest consumption of TN for 1% ADE was 88% by the wastewater algae strain AS-A1, while the least change was 26% by strain UTEX B SP23. However, the removal of total phosphorus (TP) was nearly 70% for all measured strains at 5 and 10% ADE. The maximum biomass production was in the range of 354-366 mg/L by UTEX 1237 in 10% ADE. Biological assimilation was speculated as the main reason of nitrogen and phosphorus removal as control experiments absent of algae showed minimal nutrient concentration change. In short, anaerobic digestion effluent is an economical and beneficial resource that can be used to cultivate microalgae and cyanobacteria. Selecting the combinations of robust strains and suitable effluent concentrations that yield optimal biomass and uptake of nutrients is a critical step before upscaling to industrial applications