Quantitative analysis of mycelium morphological characteristics and rifamycin B production using Nocardia mediterranei

Lee, Kye Joon; Rho, Yong Taik

doi:10.1016/0168-1656(94)90155-4

Cited by 8 publications

(14 citation statements)

References 12 publications

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“…It is possible that this excessive branching caused an increase in viscosity of the culture medium and subsequently interfered with mixing and aeration. It may be concluded that the microscopical characteristics of A. mediterranei were significantly affected by the constituents of the culture media which possibly also influenced availability of oxygen, and that rifamycin B productivity was also related to morphological changes as previously reported by Rho et al (1991) and Lee and Rho (1994).…”

Section: Discussionsupporting

confidence: 62%

“…A possible significant observation is that in all cases glucose consumption was rather slow and incomplete but occured at somewhat higher apparent rates with (NH 4 ) 2 SO 4 , 0.9% KNO 3 and 1.8% KNO 3, respectively in decreasing order ( Figure 5) especially during the trophophase. The faster utilization of glucose with (NH 4 ) 2 SO 4 than with KNO 3 was also observed by Lee and Rho (1994) and might be the cause of the lower yield of the antibiotic with (NH 4 ) 2 SO 4 in our study as explained by Pape and Rehm (1985).…”

Section: Discussionmentioning

confidence: 47%

“…In the fermentation medium (F1), the mycelia showed frequent branching followed by subsequent gradual fragmentation into short rods. Branching and fragmentation of the mycelia was also reported by Lee and Rho (1994). Several authors reported the tendency of the mycelia to fragment into short rods.…”

Section: Discussionmentioning

confidence: 78%

“…They studied the influence of various forms of inorganic nitrogen on biosynthesis of rifamycin B and found that only (NH 4 ) 2 SO 4 provided the pH levels of the fermentation broth suitable for the antibiotic biosynthesis and the highest levels of antibiotic production. However, Lee and Rho (1994) reported that inoganic nitrogen sources play an important role in determining the production profile of rifamycin B with KNO 3 showing a positive influence on antibiotic production. Accordingly, the effect of 0.9 and 1.8% KNO 3 (representing half and same nitrogen equivalent to 0.96% (NH 4 ) 2 SO 4 , respectively) was tested.…”

Section: Discussionmentioning

confidence: 99%

“…Inorganic and organic nitrogen compounds have been reported to play a key role in promoting rifamycin biosynthesis by serving either as a precursor or stimulant (Gresham and Inamine, 1986;Lee and Rho, 1994).…”

Section: Introductionmentioning

confidence: 99%

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Optimization of industrial production of rifamycin B by Amycolatopsis mediterranei. I. The role of colony morphology and nitrogen sources in productivity

El–Tayeb¹,

Salama²,

Hussein³

et al. 2004

Afr. J. Biotechnol.

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A systematic approach to process optimization for production of rifamycin B was applied to a strain of Amycolatopsis mediterranei. Examination of the growth revealed 6 different morphologically distinct colonies on Bennett's agar medium. Rifamycin B production in shake flasks by the six different colony types ranged between 0.5 and 1.2 g/l. There was a clear correlation between the colony morphology and rifamycin B productivity. The highest yield of rifamycin B (1.03-1.2 g/l) was obtained by using the orange-red colored colonies, rosette shaped, devoid of hollow center and 2-3 mm in diameter. Variability in colony morphology, however, remained and the appropriate colonies had to be picked up for preparing the inoculum of each experiment. Addition of yeast extract to the fermentation medium at different times increased rifamycin B production. The highest antibiotic production was obtained upon the addition of 0.1% yeast extract after 2 days of incubation, where the yield increased from 1.15 to 1.95 g/l (70%). The use of 1.8% KNO 3 in the fermentation medium, instead of 0.96% (NH 4 ) 2 SO 4, markedly increased rifamycin B production from 1.15 to 2.92 g/l (154%). It was also observed, upon microscopical examination, that KNO 3 decreased branching and fragmentation of the mycelia in the fermentation medium.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 47%

Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optimization of industrial production of rifamycin B by Amycolatopsis mediterranei. I. The role of colony morphology and nitrogen sources in productivity

El–Tayeb¹,

Salama²,

Hussein³

et al. 2004

Afr. J. Biotechnol.

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Developmental cycle and pharmaceutically relevant compounds of Salinispora actinobacteria isolated from Great Barrier Reef marine sponges

Hewavitharana

Webb

et al. 2012

Appl Microbiol Biotechnol

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The developmental cycle of the obligate marine antibiotic producer actinobacterium Salinispora arenicola isolated from a Great Barrier Reef marine sponge was investigated in relation to mycelium and spore ultrastructure, synthesis of rifamycin antibiotic compounds, and expression of genes correlated with spore formation and with rifamycin precursor synthesis. The developmental cycle of S. arenicola M413 on solid agar medium was characterized by substrate mycelium growth, change of colony color, and spore formation; spore formation occurred quite early in colony growth but development of black colonies occurred only at late stages, correlated with a change in spore maturity in relation to cell wall layers. Rifamycins were detected throughout the growth cycle, but changed in relative quantity at particular phases in the cycle, with a marked increase after 32 days. Expression of the spore division gene ssgA and the rifK gene for 3-amino-5-hydroxybenzoate synthase responsible for rifamycin precursor synthesis was seen even at early stages of the growth cycle. ssgA expression significantly increased between days 26 and 31, but rifK expression effectively remained constant throughout the growth cycle, consistent with the early synthesis of rifamycin. Factors other than precursor synthesis may be responsible for an observed late increase in rifamycin production. A useful approach for measuring and exploring the regulation of antibiotic synthesis and gene expression in the marine natural product producer S. arenicola has been established.

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Scaling up for the industrial production of rifamycin B; optimization of the process conditions in bench-scale fermentor

El-Sedawy

Hussein

Essam

et al. 2013

Bulletin of Faculty of Pharmacy, Cairo University

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Quantitative analysis of mycelium morphological characteristics and rifamycin B production using Nocardia mediterranei

Cited by 8 publications

References 12 publications

Optimization of industrial production of rifamycin B by Amycolatopsis mediterranei. I. The role of colony morphology and nitrogen sources in productivity

Optimization of industrial production of rifamycin B by Amycolatopsis mediterranei. I. The role of colony morphology and nitrogen sources in productivity

Developmental cycle and pharmaceutically relevant compounds of Salinispora actinobacteria isolated from Great Barrier Reef marine sponges

Scaling up for the industrial production of rifamycin B; optimization of the process conditions in bench-scale fermentor

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