A K Navarro1, A Peña, F Pérez-Guevara. 1. Department of Molecular Genetics, Institute for Cellular Physiology, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Abstract
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.
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. kurstakiHD-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.
Authors: Riekje Biermann; Laura Niemeyer; Laura Rösner; Christian Ude; Patrick Lindner; Ismet Bice; Sascha Beutel Journal: Eng Life Sci Date: 2021-12-10 Impact factor: 2.678