Dielectric monitoring of growth and sporulation of Bacillus thuringiensis

FOGALE nanotech, Nismes, Languedoc-Roussillon, France
Biotechnology Letters (Impact Factor: 1.59). 05/2005; 27(7):511-7. DOI: 10.1007/s10529-005-2543-x
Source: PubMed


On-line permittivity and optical density measurements have been used to monitor biomass concentration and sporulation status during growth of a spore-forming bacterium, Bacillus thuringiensis, in fed-batch culture. The correlation between permittivity, optical density and other observations showed three distinct phases of growth: growth itself, transition and sporulation. The permittivity variations during the transition and sporulation phases could be related to the sporulation development: the evolution pattern of the ratio of optical density to permittivity was representative of the culture state, and during the sporulation phase, a permittivity index could be build to measure the extend of spore liberation.

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    • "This problem has been widely described for recombinant protein expression in E. coli under the control of T7lac and λ promoters (Khalilzadeh et al., 2003; Shiloach and Fass, 2005; Norsyahida et al., 2009) and the main consequences are: viability loss, growth cessation or even cell death, acetate production and substrate accumulation. In addition, since dielectric permittivity measurements are sensitive to cell viability, they can be used for recognition of physiological changes during the cultivation (Markx and Davey, 1999; Kiviharju et al., 2008; Maskow et al., 2008), like the Crabtree effect in yeast cultures (Davey et al., 1996 ); overflow metabolism in E. coli fermentations (Knabben et al., 2010 ) and spore formation in Bacillus or fungi cultivations (Sarrafzadeh et al., 2005). Given on-line capacitance measurements, the probe signal can be correlated to viable cell concentration . "
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