Production, Partial Purification and Characterization of Free-and Immobilized Urease Isolated from Aspergillus Species Obtained from Long-Horned Beetles (Cerambycidae Latreille)

Abstract

Urease is a vital enzyme with applications in agriculture, environmental biotechnology, and medicine, playing a key role in metabolism and bioremediation. Despite its significance, efficient production and purification methods are still needed to meet industrial demands. This study demonstrated the production, partial purification and physicochemical properties of free-and immobilized urease from Aspergillus niger and Aspergillus ustilago isolated from the gut of Long-horned beetles. Urease production was achieved through submerged fermentation using urea as the primary substrate. Partial purification was carried out through ammonium sulfate precipitation (70 % saturation). Immobilization of the urease was successfully performed using sodium alginate, which enhanced the enzyme stability and reusability. The activities of the crude and partially purified free-urease were (1.82 and 4.82 U/mL) and (1.78 and 4.23 U/mL) for A. niger and A. ustilago respectively. The immobilized enzyme showed optimal activity at pH 7.0 and a temperature of 50 ^oC. Metal ions such as Fe²⁺, Mg²⁺, and Ca²⁺, enhanced the activity of the free-urease from A. ustilago while Al³⁺, Cu²⁺ and Co²⁺ were observed to cause inhibitory effects on free-urease from A. niger. On the other hand, with immobilized enzyme, Fe²⁺, Mg²⁺, Al³⁺ and Ca²⁺ showed a pronounced activation at both concentrations investigated. It was inferred that the immobilized urease from Aspergillus spp. was more stable with stronger affinity for all the metal ions tested. This study has provided information on the feasibility of immobilization of urease from Aspergillus spp., isolated from the gut of Long-horned beetles with biotechnological implications for industrial and medical applications such as in environmental bioremediation and biosensor development.