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A mechanized urease activity assay.

Justyna Bzura1, Robert Koncki1

  • 1University of Warsaw, Faculty of Chemistry, L. Pasteura 1, 02-093, Warsaw, Poland.

Enzyme and Microbial Technology
|January 29, 2019
PubMed
Summary

Two new flow analysis systems for urease activity assays were developed using Arduino microcontrollers. The Nessler reaction system offers higher sensitivity and lower detection limits for urease determination.

Area of Science:

  • Analytical Chemistry
  • Biochemistry
  • Environmental Science

Background:

  • Urease activity assays are crucial for various applications, including environmental monitoring and agricultural research.
  • Existing methods for urease determination can be time-consuming and require complex instrumentation.
  • There is a need for rapid, sensitive, and cost-effective methods for urease activity measurement.

Purpose of the Study:

  • To develop and compare two fully mechanized flow analysis systems for urease activity assays.
  • To evaluate the performance of the Berthelot method and the Nessler reaction for photometric detection of ammonia.
  • To assess the suitability of the developed systems for determining urease in complex biological matrices and for heavy metal inhibition assays.

Main Methods:

Keywords:
Enzyme assayFlow analysisMulticommutationUrease

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  • Development of two compact flow analysis systems utilizing Arduino microcontrollers, solenoid micropumps, and microvalves.
  • Implementation of photometric detection of ammonia using the Berthelot method and the Nessler reaction.
  • Design of dedicated optoelectronic flow-through detectors based on light-emitting diodes for both detection schemes.

    • Main Results:

    • Both systems enabled single enzyme assays within minutes, covering urease activity ranges from 0.02-5.3 U/mL.
    • The Nessler reaction-based system achieved a detection limit of 0.02 U/mL, while the Berthelot method system had a detection limit of 0.75 U/mL.
    • The Nessler reaction system demonstrated superior sensitivity, lower detection limits, better selectivity, and lower assay costs compared to the Berthelot method.

    Conclusions:

    • The developed bioanalytical flow systems are effective for urease determination in complex biological samples like plant extracts and microbial culture media.
    • The Nessler reaction-based system provides a more sensitive and cost-effective approach for urease activity assays.
    • The systems are also applicable for inhibitive determination of heavy metals at sub-ppm levels.