A SIMPLE-MODEL FOR THE OPTIMIZATION OF THE EXTRACTION YIELD OF ANTIBIOTICS ISOLATED FROM FERMENTED BROTHS BY DIRECT CRYSTALLIZATION

This article is concerned with the development of a model to maximize the overall yield of isolation of antibiotics recovered from fermented broths by the so-called direct precipitation method. In this process, as in most antibiotics isolation processes, a second filtration of th e semiexhaust mycellium from the first filtration, after slurrying it in water at the suitable pH, is required. The maximization of the over all yield of isolation implies the use of an optimal amount of water, measured as a volume to fermented broth mass ratio, which can be calcu lated by using the model derived here. The model also allows for the c alculation of the partial and overall yields of the isolation process, and its validity is demonstrated by its ability to describe reasonabl y well the isolation data of two different tetracycline-fermented brot hs produced according to two different technologies. The application o f the model requires only the knowledge of easily obtainable fermented broth parameters and is illustrated for two different types of tetrac ycline-fermented broths. Although the model had been derived for the o ptimization of the overall yield of isolation of antibiotics recovered by direct precipitation, it can easily be adapted to be used for the optimization of the overall yield of isolation of antibiotics recovere d by other isolation processes. (C) 1993 John Wiley & Sons, Inc.