Physicochemical and thermodynamic properties of purified rhodanese from A. welwitschiae LOT1 and the cyanide detoxification potential of the enzyme

Rhodanese, the primary cyanide-detoxifying enzyme, plays a crucial role in mitigating the harmful effects of cyanide present in various industrial waste materials, such as battery manufacturing effluents. The bioremediation of cyanide-contaminated environments relies on efficient detoxification mechanisms, making rhodanese a valuable enzyme for biotechnological applications. This research aimed to investigate the biochemical properties of purified rhodanese produced by Aspergillus welwitschiae LOT1, a fungal strain with promising cyanide detoxification capabilities. The purified rhodanese was obtained through fermentation, precipitation, and chromatographic separations, resulting in a homogeneous band of approximately 58 kDa with a specific activity of 374 RU/mg, 28-fold purification, and 14% recovery. The enzyme exhibited optimal cyanide detoxification at pH 7 and 60 °C, with stability observed between 30 and 50 °C and pH 8–10. All metal ions examined except for Cu²⁺ enhanced the cyanide-degrading ability of rhodanese. Notably, the enzyme demonstrated a high substrate preference for Na₂S₂O₃ and followed a first-order kinetic model and free energy, ΔG of 61.3 kJ/mol, making it a promising candidate for biotechnological applications. Overall, this study provides valuable insights into the biochemical properties of rhodanese from A. welwitschiae LOT1, highlighting its potential for efficient cyanide detoxification and bioremediation.