Heterologous protein secretion and fungal morphology in chemostat cultures of a recombinant Aspergillus niger (B1-D)

Wongwicharn, Aporn; McNeil, Brian; Harvey, Linda M.

doi:10.1016/s0141-0229(98)00139-2

Cited by 17 publications

(8 citation statements)

References 46 publications

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“…Although ethanol formation is also found with ¢lamentous fungi [16] (but we found no ethanol excretion with P. simplicissimum), the reduction of fumarate to succinate could also serve this purpose [5,17]. Such a fumarate respiration was described for bacteria (Escherichia coli [17]) and mammalian cells [18].…”

Section: Intra-and Extracellular Succinate Under Environmental or Funmentioning

confidence: 68%

Succinate synthesis and excretion by Penicillium simplicissimum under aerobic and anaerobic conditions

Gallmetzer

2002

FEMS Microbiology Letters

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Succinate is an interesting chemical for industries producing food and pharmaceutical products, surfactants, detergents and biodegradable plastics. Succinate is produced mainly by a mixed-acid fermentation process using anaerobically growing bacteria. However, succinate excretion is also widespread among fungi. In this article we report results on the intracellular concentration and the excretion of succinate by Penicillium simplicissimum under aerobic and anaerobic conditions. The intracellular concentration of succinate increased slightly with the specific growth rate and strongly if the respiratory chain was inhibited by sodium azide or anaerobic conditions (N 2 ). A strong increase of succinate excretion was observed if the respiratory chain was inhibited. It is suggested that succinate synthesis under functional (sodium azide) or environmental (N 2 ) anaerobic conditions occurs via the reductive part of the tricarboxylic acid cycle. Succinate is then excreted because the oxidative part of the tricarboxylic acid cycle is inactive. A possible role of succinate synthesis in the regeneration of NAD ('fumarate respiration') is discussed. ß

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Section: Intra-and Extracellular Succinate Under Environmental or Funmentioning

confidence: 68%

Succinate synthesis and excretion by Penicillium simplicissimum under aerobic and anaerobic conditions

Gallmetzer

2002

FEMS Microbiology Letters

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“…Fluorescence microscopy has proved a valuable tool for identifying active tips of filaments and active regions in pellets [38]. Fluorescent stains coupled with image analysis have been used in the works of Vanhoutte et al [39], Agger et al [40], Wongwicharn et al [41], Hamanaka et al [42] and Amanullah et al [13]. Vanhoutte et al [39] using a differential staining procedure and color image analysis in studies on the growth and differentiation of P. chrysogenum showed and quantified six physiological states: growing material (zone 1), three differentiated states characterized by increased granulation (zones 2,3,4), a highly vacuolated state (zone 5) and dead segments empty of cytoplasm (zone 6).…”

Section: Identification Of the Metabolically Active Fraction Of The Mmentioning

confidence: 99%

Characterization of Fungal Morphology using Digital Image Analysis Techniques

Papagianni¹

2014

J Microb Biochem Technol

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The use of filamentous fungi for the production of commercially important products is old but keeps increasing during the last decades. New classes of compounds are being added in the list of products of fungal fermentations as a result of progress in methodologies and applications of biotechnology. Fungi are morphologically complex organisms that differ in structure throughout their life cycle. In submerged fermentation fungal morphology may take distinct forms ranging from dispersed filaments to densely interwoven masses of mycelium known as pellets. Each morphological form has each own characteristics that have a critical impact on the overall process outcome. Dispersed growth results in highly viscous broths with pseudoplastic behavior that have a negative impact on mass and energy transfer rates resulting in higher energy input requirements. Due to the high industrial relevance of fungal morphology there has been a substantial development of tools and techniques to characterize morphology and extract quantitative information that can be used in process control and optimization studies. Digital image analysis is the state of the art method to characterize and quantify fungal morphology in the developmental process from spores to filamentous structures to pellets. The progress made in the area since the 1990s, when the first image analysis methods were reported, is discussed in detail throughout the review.

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“…10-L chemostat; A. niger (45) Increase in pH Larger pellets For broth pH of 4.5, 700-µ pellets; for broth pH of 2.1, 400-µ pellets; 8-L fermentation; A. niger (88) No morphologic effect 5.5 < pH < 7.0, 9-to 10-L fermentor, P. chrysogenum (89) Decrease in pH Filamentous growth Critical pH of 2.3 for filamentous growth; pellets formed in more alkaline conditions up to pH 4.5; investigation using defined medium identical dcw and glucose/ammonium uptake regardless of morphology, 1.07 × 10 5 spores/mL inoculum, A. niger (90) Decrease in DO No morphologic change 12-to 300-mmHg range examined, 9-to 10-L fermentation, P. chrysogenum (89) Increase in CO 2 in feed air Abnormal morphological Highly branched tips and swollen branch points, 12.5-L fermentation, changes P. chrysogenum (91) Longer mean hyphal 0-18% CO 2 , continuous culture, 8000-L fermentor, A. niger A60 (92) and branch length Decrease in dissolved CO 2 level Slower germination of spores 99 ± 21 vs 44 ± 14 h, 9-to 10-L fermentation, P. chrysogenum (89) a dcw, dry cell weight (g/L).…”

Section: Influences On Pellet Formationmentioning

confidence: 99%

“…There are several notable articles on the growth of A. niger and citric acid production (25,(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43), on either constitutive or heterologous enzyme production (44,45), and on organic acid production (46). Specifically, three articles give insightful overviews of the state of citric acid production at the time they were written (47)(48)(49).…”

Section: Application To Aspergillus Cultivation and Citric Acid Produmentioning

confidence: 99%

Early phase process scale-up challenges for fungal and filamentous bacterial cultures

Junker

Hesse

Burgess

et al. 2004

Appl Biochem Biotechnol

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Culture pelleting and morphology has a strong influence on process productivity and success for fungal and filamentous bacterial cultures. This impact is particularly evident with early phase secondary metabolite processes with limited process definition. A compilation of factors affecting filamentous or pelleting morphology described in the literature indicates potential leads for developing process-specific control methodologies. An evaluation of the factors mediating citric acid production is one example of an industrially important application of these techniques. For five model fungal and filamentous bacterial processes in an industrial fermentation pilot plant, process development strategies were developed and effectively implemented with the goal of achieving reasonable fermentation titers early in the process development cycle. Examples of approaches included the use of additives to minimize pelleting in inoculum shake flasks, the use of large-volume frozen bagged inoculum obtained from agitated seed fermentors, and variations in production medium composition and fermentor operating conditions. Results were evaluated with respect to productivity of desired secondary metabolites as well as process scalability. On-line measurements were utilized to indirectly evaluate the cultivation impact of changes in medium and process development. Key laboratory to pilot plant scale-up issues also were identified and often addressed in subsequent cultivations.

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Heterologous protein secretion and fungal morphology in chemostat cultures of a recombinant Aspergillus niger (B1-D)

Cited by 17 publications

References 46 publications

Succinate synthesis and excretion by Penicillium simplicissimum under aerobic and anaerobic conditions

Succinate synthesis and excretion by Penicillium simplicissimum under aerobic and anaerobic conditions

Characterization of Fungal Morphology using Digital Image Analysis Techniques

Early phase process scale-up challenges for fungal and filamentous bacterial cultures

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