Extraction And Identification Of Biosurfactant In The Penicillin Broth

Penicillin has the maximal output and the longest clinical history among all the antibiotics. It is produced by microbial zymotechnics and extracted by solvent extraction in industry. This process has its own disadvantages: The microorganism, while producing penicillin, will also excrete a lot of surface-active substances that diffuse into the broth. So becomes inevitable during solvent extraction the emulsion problem that adds up the separation difficulty, slows down the separation speed, prolonged the extraction time, increases the antibiotic loss, and reduces the extraction efficiency and product quality.In this paper we use the method of ultrafiltration to remove the surfactants in the antibiotic broth. By this means, we solve the long-lasting problem of emulsification in the solvent extraction process and thereby increase the extraction efficiency and product quality. At the same time these surface-active substances are concentrated by UF, and then collected by freeze-drying. It is shown that the UF membrane with an MWCO of 10 kD could remove the surfactants from the broth efficiently, and thereby eliminate the emulsification in the solvent extraction process. This biosurfactant is proved, through experimental analysis, to be some kind of glycoprotein of 60-70 kD or so. There is 2.659g such biosurfactant per liter antibiotic broth. Besides, we also study how the temperature and pressure could affect the UF membrane's performance, discuss the mechanism of the membrane-contamination, and clean the UF membrane with different methods and under different temperature to decide the best cleanout method and manipulative meters: At 35℃, flushing the UF membrane with pure water under manipulative pressure first, then inverting the membrane and flushing with pure water again, then cleaning the membrane with 0.4 % NaOH solution, finally flushing with pure water till litmus less.