Aeration‐agitation studies on the novobiocin fermentation

Abstract

AbstractNovobiocin fermentations in 20 l. baffled fermentors were studied as a function of the size and speed of the dual four‐bladed flat‐blade turbines used. Power input and sulphite oxidation rate measurements were made. The courses of pH, sugar utilization, mycelial dry weight, carbon dioxide evolution and antibiotic titer were determined. Optimum antibiotic yields were achieved at a power input of 0·5 h.p./100 gal, equivalent to a sulphite oxidation rate of 110 mmoles O2/l.h, when the impeller diameters were 29 per cent or 39 per cent of the tank diameter. A power input of 0·75 h.p./100 gal, equivalent to a sulphite oxidation rate of 160 mmoles O2/l.h, was required for equivalent results with the impeller diameter 49 per cent of the tank diameter. Some explanations of the lack of equivalent results with the large impeller are discussed.