Foam-Bed Bioreactor With Immobilized Aspergillus welwitschiae for Efficient Tannin Removal: Optimization and...

Tannins are polyphenolic compounds commonly found in industrial effluents posing threats to aquatic ecosystems and treatment processes due to their resistance to biodegradation. Efficient and eco-friendly removal methods are urgently needed to mitigate their environmental impact. Bioremediation using fungal systems has been recognized as an efficient and eco-friendly solution. Although fungal strains have been explored for tannin biodegradation there is limited information on the use of immobilized fungal biomass specifically Aspergillus welwitschiae, in foam-bed bioreactor systems for effective tannin removal. In the present study, a foam-bed bioreactor developed with A. welwitschiae immobilized on polyurethane foam supplemented with pomegranate peel powder (PPP) was optimized for tannin removal. The central composite design (CCD) under response surface methodology (RSM) using Design-Expert software was employed to optimize two factors: tannin concentration (A) and time (B). The developed linear model showed that time significantly affected tannin removal (p < 0.05). The optimized process achieved a maximum removal efficiency of approximately 67% from a tannin concentration of 5500 ppm in 70-min contact time under selected conditions, indicating the system's potential for eco-friendly tannin biodegradation. The foam-bed bioreactor system demonstrated effective fungal growth and substantial tannin removal. Optimization studies indicated that both tannin concentration and contact time significantly influenced degradation efficiency, resulting in high removal rates under optimal conditions. This study highlights the potential of a low-cost, eco-friendly fungal foam-bed bioreactor for efficient tannin removal, offering a promising strategy for sustainable wastewater management in agro-industrial sectors.