Brucella suis in Aerated Broth Culture

Lynn L. Gee, Philipp Gerhardt
1946 Journal of Bacteriology  
Resolution of the aeration requirements of Brucella suis in broth culture was imperative for the production of the comparatively large amounts of cells required in the extensive epidemiological and immunological project of which this study is a part. The two prime factors in sparger aeration appeared to be (1) the rate of air supply and (2) the type of sparger employed; the two factors apparently were interdependent. Thus, the more efficient the sparger in producing fine bubbles, in general the
more » ... les, in general the less air required for growth. This has been emphasized in a review of biological aeration systems by De Becge and Liebmann (1944). In the case of this organism, however, the kinds of antifoam employed with various sparger aeration systems has also been found to be of primary importance. A typical industrial type stainless steel "dishpan" sparger has 0.108-inch perforations, 49 per square inch; whereas, in contrast, one of the more efficient industrial type heat-resistant carbon spargers (grade no. 60) has an average porosity of 0.0013 inches. Consequently, a detailed study was undertaken to compare air requirements, using different sparger types along with different antifoams. If through improved aeration air requirements could be lessened while high yields were maintained, the opportunity for contamination would be reduced, and foaming of the medium decreased. Additional studies were concerned with the employment of a gradually increasing air supply, the influence of the pressure head in the system, and the value of shaking as an aeration expedient. METHODS The following three types of aeration systems were employed in these studies: (1) Shaker flasks, as reported previously (Gerhardt and Gee, 1946) , in which a high, constant, and easily reproducible rate of air supply was obtained by growing the organism in flasks incubated on a shaking machine, oscillating horizontally a distance of 3.0 inches at a rate of approximately 90 oscillations per minute. Normally, 250-mi Erlenmeyer flasks were used, containing 25 ml of medium each. (2) Aeration bottles, consisting of l-quart jars, each fitted with a rubber stopper and a sparger. Normally, 400 ml of medium were placed in each bottle. Air was supplied by maintaining a negative pressure above the medium.
doi:10.1128/jb.52.3.271-281.1946 fatcat:p2yksfr3hbdmjficjr7wendei4