Production and purification of the thermophilic bacteriophage TP-84.

A new procedure for production and purification of the thermophilic bacteriophage TP-84 in high yields is described. Cultures of Bacillus stearothermophilus strain 10, enriched with nutrients to obtain heavy growth and to prevent sporulation and maintained at a pH of 6.5, were infected with the phage in a 100-liter fermentor. Addition of magnesium chloride (0.01 M) and a temperature of 58-C were essential for maximal phage production. Phage (5 times 1011 infective particles/ml) was precipitated with polyethylene glycol (molecular weight 6,000) in the presence of sodium chloride and was further purified by cesium chloride density centrifugation.