TABLE 7.

Time course of CGP accumulation in A. calcoaceticus strain ADP1 and the cphI mutant^a

Incubation period (days)	CGP concn (g/liter)
	A. calcoaceticus ADP1	A. calcoaceticus ΔcphI
1	0.15 ± 2 × 10−3	0.001 ± 8 × 10−4
2	0.24 ± 6 × 10−3	0.006 ± 9 × 10−4
3	0.13 ± 4 × 10−3	0.042 ± 15 × 10−4
4	0.06 ± 2 × 10−3	0.061 ± 18 × 10−4

^aCells of A. calcoaceticus strain ADP1 and of the ΔcphI mutant were cultivated for 96 h at 30°C in 250-ml Erlenmeyer flasks without baffles containing 100 ml of unbuffered MSM with 10 mM ammonium sulfate as the nitrogen source. In addition, 75 mM arginine was added. The initial pH of the medium was 7.3. After 24, 48, 72, and 96 h of cultivation aliquots of the cells were harvested by centrifugation, and the cyanophycin content was analyzed by determining the amount of cyanophycin isolated by the acid extraction method. The data are means and standard deviations of three independent experiments.