Electron spin resonance of copper(II) as a tool for the determination of asparagine concentration in Bacillus subtilis cultures

A procedure is presented that is based on the detection of Cu(II)-asparagin e complexes by quantitative ESR, and allows in a very simple and rapid mann er to evaluate the changes of asparagine concentration during the entire ti me range of the growth of Bacillus subtilis in a typical growth medium. The analysis is carried out in terms of the decrease of the intensity of the E SR-active mono- and di-asparagine-copper(II) complexes. It is resulted that at the end of the exponential growth the asparagine concentration was redu ced to values as low as 2% of the initial value. The procedure here reporte d may be the basis of similar methods to be used for other amino acids and prokaryote systems. (C) 2000 Elsevier Science B.V. All rights reserved.