An Improved Laboratory-Scale Fermentor for Submerged Culture Investigations.

A small laboratory fermentor which employs mechanical agitation for the dispersion of air introduced under pressure has previously been described by Feustel and Humfeld (1946). This fermentor has an operating capacity of 500 to 2,000 ml and has been found very useful for small-scale, yeast-culturing investigations, as well as for studies on the production of subtilin activity by Bacillus subtilis (1947). Certain limitations, however, principally those of capacity and effectiveness of foam breaking, have led to the development of an improved fermentor having a larger capacity and a more effective mechanical foam breaker. This fermentor also has a stirring device, which is so designed that air for the aeration of the culture liquid can be drawn in from the atmosphere by suction created behind the stirring blades, as compared with air introduced under pressure. This paper describes the improved fermentor and some of the preliminary results obtained.