THE RELATION BETWEEN PROTEOLYTIC AND AMYLOLYTIC ENZYME PRODUCTION BY ISOLATES OF THE BACILLUS SUBTILIS GROUP

A characteristic customarily attendant upon the use of crude bacterial amylase substrates is a strong and frequently objectionable odor. This odor appears to be associated with proteolysis. From a theoretical as well as a practical view-point it appeared desirable to evaluate proteolytic enzyme production by a number of bacterial isolates of proved amylase-producing ability. Accordingly, from the group of Bacillus subtilis isolates described by Peltier and Beckord (1945) some 63 amylase producers were selected for further study. METHODS The methods used for evaluating proteolytic activity were of the survey type, one utilizing the liquefaction of gelatin by culture stabs and the other three the clearing of protein suspended in agar, by filtrates from isolates cultured on an appropriate "complete " medium. All isolates were maintained on wheat bran extract agar (Peltier and Beckord, 1945). The rate of liquefaction was determined by the inoculation of nutrient gelatin with deep stabs from a 24-hour-old inoculum grown in wheat bran extract