Nutrient broth (5 g peptone and 3 g meat extract, pH 7.0, Merck)
was used as the common growth and stock media. Growth media
was prepared at 250 ml erlenmeyer flasks containing 100 ml
nutrient broth and stock media at 50 ml erlenmeyer flasks
containing 25 ml nutrient broth. They were sterilized at 121°C for 15
minutes. 1 ml of stock medium was inoculated at the growth medium
and incubated at 30°C with 150 rpm. Growth and proteolytic activity
was measured at an interval of 2 h from the initiation of incubation.
The growth and proteolytic activity curves were obtained.