TOXIN PRODUCTION IN AERATED CULTURES OF CORYNEBACTERIUM DIPHTHERIAE

Abstract

In this paper a comparison is made between the growth and toxin production of Corynebacterium diphtheriae in aerated and classical still cultures. It is shown that in well aerated cultures fermentation proceeds more rapidly and toxin appears earlier than in still cultures. However, to obtain maximum results in aerated cultures it is necessary to increase the amount of fermentable substance over that present in the media of still cultures. When cultures are aerated with two to three volumes of air per minute and an extra amount of fermentable carbohydrates is added to the growing cultures at a suitable interval a higher yield of toxin is obtained than in still cultures in similar media. The maximum concentration of toxin, moreover, is reached in the aerated cultures after about 60 hr. of incubation as compared with about 120 hr. in still cultures.