Preparation and optimization of lyophilised MTOXPlate for toxicity testing based on eleven different microorganisms

Abstract:

[Objective] In order to simplify the procedure and improve the sensitivity of biological toxicity testing method, the lyophilised MTOXPlate based on 11 genetically diverse microorganisms was prepared. [Methods] The tested microbial strains were fixed on the microplate by the vacuum freeze-drying method. Fluorescence spectrophotometry was used to determine the effects of several cryoprotectants on the freeze dried strains with the survival rate as the selecting index. The test condition was optimized through the sensitivity of toxicity detection. [Results] When the protective agent contains 8% trehalose, 2% glucose, 2% mannitol and 1% sodium glutamate, the mean cell survival rate can reach 89.41% for 11 microbial strains used in this study. The resurrection medium and test sample were added to each well of the pre-prepared 96-well microplate at the same time. So that, short testing time and optimal detection sensitivity could be obtained. This lyophilised MTOXPlate exhibits high sensitivity and good reproducibility, which is suitable for the toxicity assessment. [Conclusion] MTOXPlate could be a new biological toxicity test technology, which can be applied to the field of ecological toxicity testing.

Key words:Eleven microorganisms, MTOXPlate, Lyophilization, Toxicity testing