Influence of oxygen tension, biomass concentration, and specific growth rate on the rheological properties of a filamentous fermentation broth

Olsvik, E. S.; Kristiansen, B.

doi:10.1002/bit.260401102

Cited by 44 publications

(21 citation statements)

References 19 publications

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“…It has been established that cell concentration, speci®c growth rate, and the dissolved oxygen concentration are factors, which will in¯uence the rheological properties of Aspergillus niger broth to a large extent [58], representing three different methods for obtaining the viscosity in the culture. A number of studies have shown that growth rate can in¯uence the morphology of ®lamentous organisms [5,26,29,72,102], whereas the dissolved oxygen tension may affect broth rheology [126] while having little in¯u-ence on the hyphal dimension [40,74,126].…”

Section: Mycelial Pellets Formationmentioning

confidence: 99%

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Understanding the morphology of fungi

Pazouki

Panda

2000

Bioprocess Engineering

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Filamentous fungi comprise an industrially very important collection of microorganisms, since they are used for the production of a wide variety of products ranging from primary metabolites to secondary metabolites and further on to industrial enzymes (such as proteases, lipases and antibiotics). It is known that fungal morphology is often considered as one of the key parameters in industrial production. For the production of fungal metabolite products, the desired morphology varies from one product to another. Many parameters affect the morphology of fungi during the process of fermentation, among them speed of agitation, speci®c growth rate, dissolved oxygen, number of spores or conidia per liter of fermentation broth are important and should be considered when higher yield is desired in the process. It is, therefore, of considerable importance to understand the mechanism underlying the morphology of the cell, its growth and product formation by ®lamentous fungi. Such knowledge may be used in the optimization of the microbial process. Several literatures with various fungi to study their morphology, relating enzyme or product production to the character of the fungi in the study is reviewed. It is also considered that how the process parameters affects the morphology. The aim of this communication is to review the relevant literature to understand the morphology of ®lamentous fungi. List of symbols bhyphal density, lm/tip D i impeller diameter, m D pellet diameter (in Eqs. 4 and 5), mm D r dilution rate, h )1 k constant, number of section used for branching (in Eq. 7) K c constant K r constant (in Eq. 5) K r linear colony radial growth rate (in Eq. 1), lm/h L e mean length of main hyphae, lm L e *mean dimensionless length, lm L t mean total length of hyphae, lm L hgu mean length of hyphal growth unit, lm M 0 dry weight of mycelia at time t 0 , g M 1 dry weight of mycelia at time t 1 , g n number of disrupted pellets N impeller speed, h )

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Section: Mycelial Pellets Formationmentioning

confidence: 99%

“…K/X, gives a simple description of the structure. The morphology of the culture has been found to increase with cell concentrations [58].…”

Section: Fragmentation Of Hyphal Elementsmentioning

confidence: 99%

Understanding the morphology of fungi

Pazouki

Panda

2000

Bioprocess Engineering

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“…Because of general problems in measuring the viscosity of filamentous organisms, it was also deemed appropriate to omit the rheological properties of the cultivation broth. Several studies showed that the complex morphology of filamentous organisms is responsible for highly viscous cultivation broths, characterised by shear-ratedependent viscosities and by yield stress [2,38,110,111]. Furthermore, the consideration of morphology and the corresponding rheology is crucial for the explanation of mass transfer in multiphase systems, as these factors influence the bubble and drop sizes of suspended air and liquids [112].…”

Section: Advances In Morphology Characterisation and Whole-broth Modementioning

confidence: 99%

The Taming of the Shrew - Controlling the Morphology of Filamentous Eukaryotic and Prokaryotic Microorganisms

Walisko

Moench-Tegeder

Blotenberg

et al. 2015

Advances in Biochemical Engineering/Biotechnology

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One of the most sensitive process characteristics in the cultivation of filamentous biological systems is their complex morphology. In submerged cultures, the observed macroscopic morphology of filamentous microorganisms varies from freely dispersed mycelium to dense spherical pellets consisting of a more or less dense, branched and partially intertwined network of hyphae. Recently, the freely dispersed mycelium form has been in high demand for submerged cultivation because this morphology enhances the growth and production of several valuable products. A distinct filamentous morphology and productivity are influenced by the environment and can be controlled by inoculum concentration, spore viability, pH value, cultivation temperature, dissolved oxygen concentration, medium composition, mechanical stress or process mode as well as through the addition of inorganic salts or microparticles, which provides the opportunity to tailor a filamentous morphology. The suitable morphology for a given bioprocess varies depending on the desired product. Therefore, the advantages and disadvantages of each morphological type should be carefully evaluated for every biological system. Because of the high industrial relevance of filamentous microorganisms, research in previous years has aimed at the development of tools and techniques to characterise their growth and obtain quantitative estimates of their morphological properties. The focus of this review is on current advances in the characterisation and control of filamentous morphology with a separation of eukaryotic and prokaryotic systems. Furthermore, recent strategies to tailor the morphology through classical biochemical process parameters, morphology and genetic engineering to optimise the productivity of these filamentous systems are discussed.

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“…The cell growth is particularly affected by stress conditions in the broth. The study of rheological properties influenced by morphological changes in the fermentation broth is of industrial importance, and is indispensable to enhance the yield of the desired product as it depends on the biomass cultured 3 . The filamentous nature of actinomycetes leads to viscous fermentation broths with shear thinning nature 4 .…”

Section: Introductionmentioning

confidence: 99%

Rheological Characterization of Streptomyces roseosporus for the Production of Daptomycin

Chakravarty¹

2017

Chem.Biochem.Eng.Q.

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Daptomycin is a potential broad-spectrum anti-MRSA antibiotic produced by Streptomyces roseosporus. It has been a boon for patients with complicated skin and skin structure infections. There is a constant urge to enhance the yield of Daptomycin to reduce the cost of its industrial production. Daptomycin fermentation is a highly aerobic process, and the fermentation broth exhibits typical rheological properties, which peculiarly govern the production phenomenon. Being a secondary metabolite, Daptomycin is a non-growth associated product. Sufficient cell mass promises better production. The cell growth is particularly affected by stress conditions in the broth. In this study, the effects of stress conditions on broth characteristics were evaluated. Different rheological models were plotted and the Power law model was found to be best-fitted. The consistency index (K) and the flow behavior index (n) data were calculated. This study should contribute to predict and control the rheology of large-scale Daptomycin fermentation.

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Influence of oxygen tension, biomass concentration, and specific growth rate on the rheological properties of a filamentous fermentation broth

Cited by 44 publications

References 19 publications

Understanding the morphology of fungi

Understanding the morphology of fungi

The Taming of the Shrew - Controlling the Morphology of Filamentous Eukaryotic and Prokaryotic Microorganisms

Rheological Characterization of Streptomyces roseosporus for the Production of Daptomycin

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