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Updated: Jun 2, 2026
10:05
Colorimetric Detection of Bacteria Using Litmus Test
Published on: September 17, 2016
A lysozyme and magnetic bead based method of separating intact bacteria
Ebru Diler1, Ursula Obst, Katja Schmitz
1Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT)-Northern Campus, Eggenstein-Leopoldshafen, Germany.
Analytical and Bioanalytical Chemistry
|May 17, 2011
Summary
A novel method uses mutated lysozymes on magnetic beads to capture viable but noncultivable (VBNC) bacteria, overcoming limitations in standard contamination detection for water and food safety.
Area of Science:
- Microbiology
- Biotechnology
- Molecular Biology
Background:
- Bacterial viable but noncultivable (VBNC) state poses challenges for standard contamination detection methods.
- Cultivation-based detection fails for VBNC bacteria and low cell densities in food and water.
- Effective methods are needed to identify viable bacteria that do not grow on media.
Purpose of the Study:
- To develop a molecular-biological separation method for capturing VBNC bacteria.
- To create a specific bacterial capture system using engineered lysozymes.
- To enable detection of viable bacteria in complex matrices like water.
Main Methods:
- Point-mutated lysozymes (LysE35A, LysE35Q) with no muramidase activity were engineered.
- Mutated lysozymes were expressed in Pichia pastoris and purified.
- Proteins were immobilized on magnetic beads for bacterial capture and magnetic separation.
Main Results:
- Engineered lysozymes successfully captured Syto9-marked Micrococcus luteus cells.
- Immobilized mutated lysozymes demonstrated specific affinity for bacterial cell wall components.
- Fluorescence microscopy confirmed the capture of bacteria by the functionalized magnetic beads.
Conclusions:
- Mutated lysozymes on magnetic beads provide a viable strategy for specific bacterial capture.
- This method effectively addresses the challenge of detecting VBNC bacteria.
- The approach shows promise for improved pathogen detection in the food and water industries.
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