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Physical Isolation of Endospores from Environmental Samples by Targeted Lysis of Vegetative Cells
Published on: January 21, 2016
Endospore dipicolinic acid detection during Bacillus thuringiensis culture
A K Navarro1, A Peña, F Pérez-Guevara
1Department of Molecular Genetics, Institute for Cellular Physiology, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Aims:
The aim of this work was to detect Bacillus thuringiensis endospore production during fermentation under conditions hindering endospore detection, i.e. in a complex undefined industrial medium with a high content of solids in suspension.
Methods And Results:
Bacterial endospore production was measured using the photoluminescence of dipicolinate (DPA) with Tb3+. The high temperature and pressure of a conventional autoclave was used to release DPA from the endospores. The endospore was obtained from B. thuringiensis var. kurstaki HD-73 fermentations in industrial-type media with 25.1 and 54.1 g l(-1) glucose, 4.4 and 35.3 g l(-1) soybean meal, 5.8 g l(-1) yeast extract, 9.2 g l(-1) corn steep solids and mineral salts.
Conclusions:
In this study, we successfully determined the DPA concentrations during the culture of B. thuringiensis in high-concentration soybean meal media. A good correlation was found between microscope endospore counting and DPA measurements in the cultures.
Significance And Impact Of The Study:
Because of synergy between Cry protein and endospore in B. thuringiensis bioinsecticides formulation, it is important to be able to determine endospore development during B. thuringiensis industrial-type fermentation, in order to ascertain the beginning of sporulation.
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