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

• Main Authors: Elsayed, Elsayed Ahmed, Omar, Hoda Gamal, El-Enshasy, Hesham Ali
• Format: Article
• Language: English
• Published: Instituto de Tecnologia do Parana 2015
• Subjects: TP Chemical technology
• Online Access: http://eprints.utm.my/id/eprint/58292/1/ElsayedAhmedElsayed2015_DevelopmentofFed-BatchCultivationStrategyforEfficientOxytetracycline.pdf; http://eprints.utm.my/id/eprint/58292/; http://dx.doi.org/10.1590/S1516-89132015050184

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 produced 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.