Development of fed-batch cultivation strategy for efficient oxytetracycline production by Streptomyces rimosus at semi-industrial scale

Journal Article

El-Enshasy, yed Ahmed Elsayed, Hoda Gamal Omar and Hesham Ali . 2015

• المجلة \ الصحيفة: Braz. Arch. Biol. Biotechnol
• رقم العدد: 5
• رقم الإصدار السنوي: 58
• الصفحات: 676-685

مستخلص المنشور

Oxytetracycline (OTC) production by  Streptomyces rimosus  was studied in batch and fed-batch cultures in shake flask and bioreactor levels using semi-defined medium. First, the effect of glucose concentration on OTC production and growth kinetics was studied intensively. The optimal glucose concentration in the medium was 15 g/L. Higher glucose concentrations supported higher biomass production by less volumetric and specific antibiotic production. Based  on  these  data,  cultivations  were  carried  out  at  semi-industrial  scale  15  L  bioreactor  in  batch  culture.  At bioreactor level, cell growth and OTC production were higher compared to the shake flask culture by about 18 and 38%, respectively. During the bioreactor cultivation, glucose was totally consumed after only 48 h. Thus, the fed batch experiment  was  designed  for  mono-glucose  feeding  and  complete  medium  feeding  to  increase  the  OTC production by overcoming carbon limitations. The results showed that the fed-batch culture using constant glucose feeding strategy with rate of 0.33 g/L/h pro duced 1072 mg/L. On the other hand, feeding with complete medium resulted in 45% higher biomass but less OTC production by about 26% compared to mono -glucose fed culture. A further improvement in this process was achieved in by keeping the dissolved oxygen  (DO) value at 60% saturation by  cascading  the  glucose  feeding  pump  with  the  DO  controller.  The  later  feeding  strategy  resulted  in  higher antibiotic production, reaching 1414 mg/L after 108 h.