Efficacy assessment of photosynthetic bacteria to meet sustainable wastewater treatment in red hybrid Tilapia (Oreochromis spp.) tank culture system

Aquaculture plays a critical role in global food production, with tilapia being a highly adaptable species capable of thriving in high-density environments. However, poor water quality in intensive aquaculture systems negatively impacts fish health and production. Excessive waste accumulation leads to increased levels of ammonia, nitrite, and nitrate, posing significant risks to both fish and environmental sustainability. Phototrophic sulfur bacteria (PSB) have been recognized for their ability to remove nutrients, heavy metals, and organic pollutants, offering a sustainable approach to wastewater treatment in aquaculture. This study evaluates the efficacy of isolated PSB compared to commercially available PSB in improving water quality in red hybrid tilapia (Oreochromis spp.) culture systems. A controlled laboratory experiment was conducted with three treatment groups: a negative control (T1), a positive control with commercial PSB (T2), and an experimental group with isolated PSB (T3). Key water quality parameters—including ammonia, nitrite, nitrate, pH, dissolved oxygen (DO), turbidity, total dissolved solids (TDS), conductivity, and temperature—were monitored at seven-day intervals over two months. Growth performance was assessed based on weight gain, specific growth rate (SGR), survival rate, and feed conversion ratio (FCR). Statistical analysis using ANCOVA determined significant treatment effects. Results showed that the isolated PSB-treated tank achieved a substantial reduction in ammonia (from 8.0 to 1.0 ppm), nitrite (from 5.0 to 0.3 ppm), and nitrate (from 160.0 to 5.0 ppm). The pH remained stable (6.5–7.5), turbidity and TDS decreased, and DO levels exceeded 5.0 mg/L, indicating improved water quality. Growth performance in the isolated PSB group was superior, with significantly higher weight gain and SGR compared to the controls (P < 0.05), suggesting enhanced fish health. The isolated PSB represents a promising, eco-friendly approach for sustainable wastewater treatment in tilapia aquaculture. This study underscores the potential of PSB in optimizing water quality, promoting fish health, and advancing environmentally responsible aquaculture. Future research should focus on large-scale implementation and refining PSB formulations for enhanced commercial viability, suggesting enhanced fish health. The isolated PSB represents a promising, eco-friendly approach for sustainable wastewater treatment in tilapia aquaculture. This study underscores the potential of PSB in optimizing water quality, promoting fish health, and advancing environmentally responsible aquaculture. Future research should focus on large-scale implementation and refining PSB formulations for enhanced commercial viability.