Growth of marine diatoms on aquaculture wastewater supplemented with nanosilica

The aquaculture industry is a significant producer of highly nutritious food for the increasing global population. However, the wastewater generated from aquaculture ponds is an emerging global issue. The present study demonstrates the culturing of marine diatoms (Chaetoceros gracilis and Thalassiosira weissflogii) in different proportions of aquaculture wastewater (AQW) coupled with inductively coupled plasma nanosilica (ICP-SiO2) and further explores their biorefinery potential concomitant nutrient removal. Thalassiosira weissflogii showed maximum carbohydrate content (79.47 +/- 0.21 mg g(-1)) in 10% and protein content (27.09 +/- 0.21 mg g(-1)) in 30% AQW: ICP-SiO2. Chaetoceros gracilis showed maximum carbohydrate content (91.64 +/- 0.11 mg g(-1)) in 50% and protein content (27.75 +/- 0.05 mg g(-1)) in 10% AQW: ICP-SiO2 respectively. Additionally, Chaetoceros gracilis showed maximum nitrate uptake in 30%, phosphate in 50%, and ammonia in 50% AQW: ICP-SiO2. While Thalassiosira weissflogii showed maximum nitrate, phosphate, and ammonia removal efficiency in 50%, 50%, and 10% AQW: ICP-SiO2 respectively. The study draws attention towards the utilization of diatoms in AQW treat-ment, aquafeed potential thus imparting a global circular bioeconomy.