Temperature‐dependent inactivation and catalysis rates of plant‐based ureases for engineered biomineralization

Abstract

Engineered (bio)mineralization uses the enzyme urease to catalyze the hydrolysis of urea to promote carbonate mineral precipitation. The current study investigates the influence of temperature on ureolysis rate and degree of inactivation of plant-sourced ureases over a range of environmentally relevant temperatures. Batch experiments at 30◦C demonstrated that jack bean meal (JBM) has a 1.7 to 56 times higher activity (844 μmol urea hydrolyzed g−1 JBM min−1) than the other tested plant-sourced ureases (soybean, pigeon pea and cottonseed). Hence, ureolysis and enzyme inactivation rates were evaluated for JBM at temperatures between 20◦C and 80◦C. A combined first-order urea hydrolysis and first-order enzyme inactivation model described the inactivation of urease over the investigated range of temperatures. The temperature-dependent rate coefficients (kurea) increased with temperature and ranged from 0.0018 at 20◦C to 0.0249 L g−1 JBM min−1 at 80◦C; JBM urease became ≥50% inactivated in as little as 5.2 minutes at 80◦C and in as long as 2238 minutes at 50◦C. The combined urea hydrolysis kinetics and enzyme inactivation model provides a mathematical relationship useful for the design of biomineralization technologies and can be incorporated into reactive transport models