An Improved Method for Determining Urease Activity from Electrical Conductivity Measurements

Area of Science:

• Biochemistry
• Analytical Chemistry
• Environmental Science

Background:

• Urease activity is crucial for nitrogen cycling and soil health.
• Accurate measurement of urease activity is essential for various applications.
• Traditional assays, like Nessler's reagent, can be time-consuming and costly.

Purpose of the Study:

• To develop an improved, cost-effective method for determining urease activity.
• To establish a reliable correlation between electrical conductivity (EC) changes and urease concentration.
• To validate the new EC-based method against a standard colorimetric assay.

Main Methods:

• Utilized chemical equilibrium modeling (PHREEQC) and empirical equations to relate EC to ammonium and urea concentrations.
• Developed a function linking the increase in EC during urea hydrolysis to urease activity.
• Employed continuous EC measurements in a closed reactor system for real-time monitoring.

Main Results:

• Successfully established a function correlating EC increase to urease activity.
• Obtained a time-dependent urea substrate concentration profile.
• Demonstrated comparable accuracy to Nessler's reagent for commercial jack bean urease.

Conclusions:

• The developed EC-based method provides an inexpensive and accurate means to determine urease activity.
• This approach offers a valuable alternative for routine urease activity assessment.
• The method is applicable across diverse research and industrial settings.