Production of bacteriophage T7.

Bacteriophage T7 was grown with Escherichia coli B as the host organism in 3- and 20-liter vessels. Under the best growth conditions devised, the yields of T7 in the culture lysates averaged 1.33 x 10(12) and 0.95 x 10(12) plaque-forming units per ml, respectively, compared with the best previously reported yields of 10(11) to 3 x 10(11) plaque-forming units per ml in 1-liter batches grown in the presence of air, or double this in similar batches grown in the presence of oxygen. The bacteriophage was purified by a simple method which gave average yields of 143 mg/liter and 131 mg/liter from the 3- and 20-liter batches, respectively. The efficiency of plating of the final material ranged from 18 to 42%. The purified bacteriophage is a convenient source of monodisperse deoxyribonucleic acid, the molecular weight of which is about 25 x 10(6).