The genetically-engineered Escherichia coli strain, DPD2540, which contains a fabA::luxCDABE fusion gene, gives a bioluminescent output when membrane fatty acid synthesis is needed. For more practical application of this strain in the field as biosensor, freeze-drying was adopted. A 12% sucrose solution with Luria-Bertani (LB) broth, as determined by the viability after freeze-drying, was found to be the most effective composition for lyophilization solution among various compositions tested. Rapid freezing with liquid nitrogen also gave the best viability after freeze-drying as compared to samples frozen at -70°C and -20°C. The biosensing activities of the cells showed a greater sensitivity when the cells from the exponential phase were freeze-dried. Finally, the optimum temperature for use of the freeze-dried cells in the biosensor field was determined.
- Optimum freezing and monitoring temperatures
- Recombinant bioluminescent bacteria
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology
- Biomedical Engineering