Cyanobacteria-based bioremediation and biomass recovery from agro-industrial wastewater

Cyanobacteria offer a sustainable and cost-effective approach to wastewater bioremediation due to their adaptability and nutrient removal efficiency. This study assessed the performance of Synechocystis sp., Synechococcus sp., and Oscillatoria sp. in treating agro-industrial wastewater, while evaluating the potential of such wastewater as a growth medium for large-scale cyanobacterial biomass production. Two wastewater sources, agricultural runoff water (AROW) and poultry meat processing effluent, were tested at 25% and 50% dilutions under controlled laboratory conditions for 15 days. Growth (OD₆₈₀) and changes in physicochemical parameters (pH, EC, TDS, DO, BOD5, COD, NO₃⁻, PO₄³⁻) were monitored. All strains achieved growth comparable to or exceeding the synthetic BG-11 control medium, with Synechocystis sp. showing the highest growth in 25% AROW. Significant pollutant reductions were recorded (70–90%, p < 0.05) across treatments; notably, Synechocystis sp. and Oscillatoria sp. removed up to 95% and 98% of NO₃⁻ and PO₄³⁻, respectively, in 25% wastewater. This preliminary assessment focused on several key physicochemical parameters, primarily nitrate, phosphate, and COD as indicators of bioremediation potential; assessment of additional contaminants is warranted for broader remediation claims. This study reveals that diluted agricultural run-off water can support superior cyanobacterial biomass production and nutrient removal compared to 25% and 50% diluted BG-11 media, demonstrating its potential as a nutrient-rich alternative substrate that reduces the need for synthetic nutrient supplementation that simultaneously enables wastewater treatment and biomass cultivation for scalable bioprocess applications.