FERMENTATION EFFICIENCY NEW-TYPE EXTERNAL-LOOP EQUIPMENTS

The purpose of this study was to investigate an external-loop reactor with plates (ELF reactor) in fermentation. Based on experiences with E LF reactors as chemical reactors and gas absorbers [1] an external-loo p fermenter was built with 1 or 2 valve plates to measure aeration of Saccharomyces cerevisiae (baker's yeast) in batch, fed-batch and conti nuous fermentation. The growth of Saccharomyces cerevisiae (respiratio n) needs a high rate of dissolved oxygen so its aeration can be used a s a classification method of reactors and fermentors. On the base of b atch and fed-batch fermentations it was established that the aeration period (time-period while a yeast particle returns to the external-loo p for new aeration) had the highest effect to the cell growth, therefo re this time was reduced in continuous fermentation culture. The incre ase of plate number and recycle flow rate of inlet fermentation media had the best influence to specific product rates. The final result was that the fermentation of yeast can be economic in this type of extern al-loop reactor. This valve plate is not sensitive to the solid partic les, therefore it could be fitted for other aerobe fermentations, for example waste water treatment.