Mycelial morphology and metabolite production

Braun, Sergei; Vecht-Lifshitz, Susan E.

doi:10.1016/0167-7799(91)90191-j

Cited by 143 publications

(74 citation statements)

References 17 publications

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“…All of these observations together make it difficult to establish a general relationship between morphology and antibiotic production (12). Complexity increases when physicochemical and genetic factors that also influence aggregation are considered (6). The lack of a coherent developmental model in streptomycetes has made it impossible to precisely describe reliable phenotypes in order to analyze and optimize fermentation processes.…”

Section: Discussionmentioning

confidence: 99%

Mycelium Differentiation and Antibiotic Production in Submerged Cultures ofStreptomyces coelicolor

Manteca

Álvarez

Salazar

et al. 2008

Appl Environ Microbiol

141

162

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Despite the fact that most industrial processes for secondary metabolite production are performed with submerged cultures, a reliable developmental model for Streptomyces under these culture conditions is lacking. With the exception of a few species which sporulate under these conditions, it is assumed that no morphological differentiation processes take place. In this work, we describe new developmental features of Streptomyces coelicolor A3(2) grown in liquid cultures and integrate them into a developmental model analogous to the one previously described for surface cultures. Spores germinate as a compartmentalized mycelium (first mycelium). These young compartmentalized hyphae start to form pellets which grow in a radial pattern. Death processes take place in the center of the pellets, followed by growth arrest. A new multinucleated mycelium with sporadic septa (second mycelium) develops inside the pellets and along the periphery, giving rise to a second growth phase. Undecylprodigiosin and actinorhodin antibiotics are produced by this second mycelium but not by the first one. Cell density dictates how the culture will behave in terms of differentiation processes and antibiotic production. When diluted inocula are used, the growth arrest phase, emergence of a second mycelium, and antibiotic production are delayed. Moreover, pellets are less abundant and have larger diameters than in dense cultures. This work is the first to report on the relationship between differentiation processes and secondary metabolite production in submerged Streptomyces cultures.Streptomyces is a soil bacterium that produces numerous clinically useful antibiotics (1, 54, 66), as well as many molecules that affect eukaryotic systems, such as inducers of eukaryotic cellular differentiation, inducers and inhibitors of apoptosis (59), and protein C kinase inhibitors with antitumor activity (such as staurosporine and others) (48, 57). Moreover, its remarkably complex developmental cycle makes this microorganism an interesting subject for study. The traditional developmental cycle of this bacterium describes two differentiated mycelial structures, a substrate (vegetative) mycelium and an aerial (reproductive) mycelium (10,25,33). In the substrate mycelium, septa are thought to be widely spaced and to define compartments containing several nucleoids (10, 63). After a short growth arrest phase characterized by reduced macromolecular synthesis (25), aerial hyphae develop from simple branching from substrate mycelium (29). Finally, the tips of the aerial mycelium differentiate into hydrophobic spore chains (8). Recently, we have been able to extend what is known about the developmental cycle in surface confluent cultures a great deal. Our main contribution has been to reveal the existence of a very young compartmentalized mycelium that dies following an orderly pattern, leaving alternating live and dead segments in the same hypha (37). Subsequently, the remaining live mycelium grows in successive waves that vary according to the density of the ...

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Section: Discussionmentioning

confidence: 99%

Mycelium Differentiation and Antibiotic Production in Submerged Cultures ofStreptomyces coelicolor

Manteca

Álvarez

Salazar

et al. 2008

Appl Environ Microbiol

141

162

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“…for several other fungal strains forming pellets (Wittler et al, 1986;Braun & Vecht-Lifshitz, 1991).…”

Section: Ultrastructure Of P Chrysosporium Hyphae In Pelletsmentioning

confidence: 99%

“…The disadvantages of dispersed mycelial growth include increased wall growth and reduction in efficiency of mixing and oxygen supply to the cells due to increased viscosity of the medium (Schügerl et al 1983). These problems may be solved to some extent by growth in the form of pellets, which also optimizes harvesting owing to the improved filtration characteristics of the broth (Braun & Vecht-Lifshitz, 1991).…”

Section: Introductionmentioning

confidence: 99%

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In situ localization of manganese peroxidase production in mycelial pellets of Phanerochaete chrysosporium

Jimenez-Tobon

Kurzątkowski²,

Rozbicka³

et al. 2003

Microbiology

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The ultrastructure of Phanerochaete chrysosporium hyphae from pellets in submerged liquid cultures was investigated in order to learn more about the interrelation between fungal architecture and manganese peroxidase (MnP) production. At day 2 of cultivation, some subapical regions of hyphae in the outer and middle zones of the pellet initiated differentiation into intercalary thick-walled chlamydospore-like cells of about 10 mm diameter. At the periphery of the cytoplasm of these cells, a large number of mitochondria and Golgi-like vesicles were observed. The sites of MnP production were localized at different stages of cultivation by an immunolabelling procedure. The immunomarker of MnP was mainly concentrated in the chlamydospore-like cells and principally distributed in Golgi-like vesicles located at the periphery of the cytoplasm. The apices of hyphae in the outer layer of the pellets were apparently minor sites of MnP production. Maximal MnP release into the culture supernatant coincided with apparent autolysis of the chlamydospore-like cells. Production of extracellular autolytic chitinase and protease coincided with the disappearance of these structures from the pellets. The chlamydospore-like cells observed in the mycelial pellets of P. chrysosporium could be metabolically active entities operating as an enzyme reservoir, delivering their content into the surrounding medium possibly by an enzyme-mediated autolytic process.

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“…For this purpose, airlift loop reactors are appropriate because of a high mass transfer rate between gas and liquid phases compared to the other types of reactors. The advantages of such reactors to stirred tank ones are simplicity, lower energy consumption, easier maintenance and lower shear stress (Braun and Vecht, 1991 [2]) which may cause damage to microorganisms. Airlift loop reactors were used for the first time by Lefrancois et al [12].…”

Section: Introductionmentioning

confidence: 99%

Modeling and control of dissolved oxygen concentration in the fermentation of Glucose to Gluconic Acid

Kazemi

Bamdad

Papari

et al. 2013

Per. Pol. Chem. Eng.

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Mycelial morphology and metabolite production

Cited by 143 publications

References 17 publications

Mycelium Differentiation and Antibiotic Production in Submerged Cultures ofStreptomyces coelicolor

Mycelium Differentiation and Antibiotic Production in Submerged Cultures ofStreptomyces coelicolor

In situ localization of manganese peroxidase production in mycelial pellets of Phanerochaete chrysosporium

Modeling and control of dissolved oxygen concentration in the fermentation of Glucose to Gluconic Acid

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