10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 4 2015 (October - December) Erythromycin is prepared from fresh strains of lessThan i greaterThan Saccharopolyspora erythraea lessThan /i greaterThan which was maintained and improved in our laboratory. The spores of lessThan i greaterThan S.erythraea lessThan /i greaterThan from czapeck slant were taken and two loops full were transferred into the seed medium (20 ml) and placed on a rotary shaker for 48hours. The seed (1 ml) was aseptically transferred into 50 ml of fermentation medium and kept for incubation on a rotary shaker for 5 lessThan sup greaterThan th lessThan /sup greaterThan , 6 lessThan sup greaterThan th lessThan /sup greaterThan , 7 lessThan sup greaterThan th lessThan /sup greaterThan and 8 lessThan sup greaterThan th lessThan /sup greaterThan days to obtain the optimum period of incubation. With the extended period of fermentation it was seen that the concentration of erythromycin, enzyme (alkaline phosphatase) activity and its protein content started decreasing from the 7 lessThan sup greaterThan th lessThan /sup greaterThan day (168 Hours) of fermentation. So it can be said that at the 6 lessThan sup greaterThan th lessThan /sup greaterThan day (144 hours) of incubation of the product of antibiotic attained its peak as well as the enzyme activity and the protein content. BIPLAB KUMAR CHAKRA, DR.SUNIL KUMAR MANDALAND DR. TAPAN KUMAR CHATTERJEE Fermentation, Alkaline Phosphatase, Czapek slant, Nutrient Broth. 603-608