Oxytetracycline production by free and immobilized cells of Streptomyces rimosus in batch and repeated batch cultures

El‐Enshasy, Hesham A.; Farid, Mohamed A.; El‐Diwany, Ahmed I.

doi:10.1016/s0921-0423(96)80060-8

Cited by 2 publications

(1 citation statement)

References 13 publications

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“…This has been attributed to C-source depletion, which activates certain molecular mechanism, i.e. proteolytic cascades and nucleases, which in turn results in decreased cell proliferation, differentiation and cell death [34–36].…”

Section: Discussionmentioning

confidence: 99%

Enhanced Natamycin production by Streptomyces natalensis in shake-flasks and stirred tank bioreactor under batch and fed-batch conditions

2019

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Background Natamycin is an antifungal polyene macrolide antibiotic with wide applications in health and food industries. Currently, it is the only antifungal food additive with the GRAS status (Generally Regarded as Safe). Results Natamycin production was investigated under the effect of different initial glucose concentrations. Maximal antibiotic production (1.58 ± 0.032 g/L) was achieved at 20 g/L glucose. Under glucose limitation, natamycin production was retarded and the produced antibiotic was degraded. Higher glucose concentrations resulted in carbon catabolite repression. Secondly, intermittent feeding of glucose improved natamycin production due to overcoming glucose catabolite regulation, and moreover it was superior to glucose-beef mixture feeding, which overcomes catabolite regulation, but increased cell growth on the expense of natamycin production. Finally, the process was optimized in 7.5 L stirred tank bioreactor under batch and fed-batch conditions. Continuous glucose feeding for 30 h increased volumetric natamycin production by about 1.6- and 1.72-folds in than the batch cultivation in bioreactor and shake-flasks, respectively. Conclusions Glucose is a crucial substrate that significantly affects the production of natamycin, and its slow feeding is recommended to alleviate the effects of carbon catabolite regulation as well as to prevent product degradation under carbon source limitation. Cultivation in bioreactor under glucose feeding increased maximal volumetric enzyme production by about 72% from the initial starting conditions.

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Section: Discussionmentioning

confidence: 99%

Enhanced Natamycin production by Streptomyces natalensis in shake-flasks and stirred tank bioreactor under batch and fed-batch conditions

2019

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Effect of support materials on antibiotic MSW2000 production by immobilized Streptomyces violatus

el-Naggar

Hassan

Said

et al. 2003

J. Gen. Appl. Microbiol.

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The production of an antibiotic by free and immobilized cells of Streptomyces violatus through entrapment or adsorption on different materials was investigated. S. violatus entrapped in Ca-alginate beads gave low antibiotic activity compared to the free cell or adsorbed cell, while the adsorption of S. violatus on sponge cubes yielded the highest antibiotic concentration after 4 days of incubation in static cultures. A starch concentration of 10 g/L was optimum for the production of the antibiotic by adsorbed cells. The weight and size of the sponge cubes used for immobilization influenced production of the antibiotic and the optimum weight and size of the sponge were 0.8 g and 1.0 cm(3), respectively, yielding a maximum antibiotic production of 280 mg/ml. Maximum antibiotic production was obtained at an initial pH value of 7.5 and in an inoculum size of 3 ml (spore suspension) per 50 ml. The production of the antibiotic in a fixed-bed bioreactor reached a maximum value after 2 days of incubation at a circulation rate of 30 ml/h. The immobilized cells in the bioreactor were reused seven successive times over a period of 14 days.

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Oxytetracycline production by free and immobilized cells of Streptomyces rimosus in batch and repeated batch cultures

Cited by 2 publications

References 13 publications

Enhanced Natamycin production by Streptomyces natalensis in shake-flasks and stirred tank bioreactor under batch and fed-batch conditions

Enhanced Natamycin production by Streptomyces natalensis in shake-flasks and stirred tank bioreactor under batch and fed-batch conditions

Effect of support materials on antibiotic MSW2000 production by immobilized Streptomyces violatus

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