SUMMARY: type A (13124) was grown in bottles (static culture) and in fermenters (batch and continuous culture) in a proteose peptone medium supplemented with phosphate, cysteine, vitamins and different carbohydrates. The lag phase was shorter and the growth rate higher when the medium was pre-reduced. The final yields of bacteria, phospholipase C, and theta-haemolysin were also significantly higher in the pre-reduced medium. The optimum pH for maximum bacterial yield was 7·0 and the optimum temperature for growth was 37°C. The formation of phospholipase C was optimum between pH 6·0 and 7·0 and for theta-haemolysin between pH 7·0 and 7·5. The optimum temperaure for synthesis of both phospholipase C and theta-haemolysin was 37°C. Culture under controlled conditions gave more reproducible production of these two proteins than experiments in bottles. The cultures reached the stationary phase before phospholipase C activity started to decline, while theta-haemolysin activity was stable. The strain was also grown in continuous culture at a dilution rate of 0·4 h, at pH 7·0 and 37°C, with a yield of 1·2 mg dry wt/ml in the complex medium supplemented with glucose (5 g/l). After the continuous feed was started the activity of phospholipase C declined very rapidly to zero, while theta-haemolysin continued to be produced at a constant level. Thus continuous culture offered no benefit over batch culture for reproducible laboratory-scale production of phospholipase C.


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