Isolation of a fluffy mutant of <i>Aspergillus niger</i> from chemostat culture and its potential use as a morphologically stable host for protein production

Vondervoort, Peter J. I. van de; Poulsen, Bjarne Rask; Ruijter, George J. G.; Schuleit, Tina; Visser, Jaap; Iversen, Jens

doi:10.1002/bit.20046

Cited by 6 publications

(3 citation statements)

References 36 publications

(50 reference statements)

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“…3) (36,240). As no known sexual cycle had been found for several species (including A. fumigatus, A. niger, A. flavus, and A. parasiticus) for many years, the parasexual cycle has been applied widely for gene identification, the generation of new strains, and linkage mapping for these species (42,59,128,159,201,229,230,278,295). Although a parasexual cycle has been defined for many Aspergillus species, relatively less was known about its evolutionary importance until recently.…”

Section: Vol 74 2010 the Evolution Of Sex 307mentioning

confidence: 99%

The Evolution of Sex: a Perspective from the Fungal Kingdom

Lee

et al. 2010

Microbiol Mol Biol Rev

322

344

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SUMMARY Sex is shrouded in mystery. Not only does it preferentially occur in the dark for both fungi and many animals, but evolutionary biologists continue to debate its benefits given costs in light of its pervasive nature. Experimental studies of the benefits and costs of sexual reproduction with fungi as model systems have begun to provide evidence that the balance between sexual and asexual reproduction shifts in response to selective pressures. Given their unique evolutionary history as opisthokonts, along with metazoans, fungi serve as exceptional models for the evolution of sex and sex-determining regions of the genome (the mating type locus) and for transitions that commonly occur between outcrossing/self-sterile and inbreeding/self-fertile modes of reproduction. We review here the state of the understanding of sex and its evolution in the fungal kingdom and also areas where the field has contributed and will continue to contribute to illuminating general principles and paradigms of sexual reproduction.

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Section: Vol 74 2010 the Evolution Of Sex 307mentioning

confidence: 99%

The Evolution of Sex: a Perspective from the Fungal Kingdom

Lee

et al. 2010

Microbiol Mol Biol Rev

322

344

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“…FL morphotypes are not uncommon in filamentous fungi. Previous studies with A. niger and A. oryzae, when grown in glucose-limited chemostats, have given rise to fluffy morphotypes (Van De Vondervoort et al, 2004;Withers et al, 1994). The fluffy phenotype we see might be different than those found in most of the other studies.…”

Section: Discussioncontrasting

confidence: 88%

The role of tradeoffs among life-history traits in a filamentous fungus

Nandimath

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Rich resource Mycelium dense and compact for resource exploitation Poor resource Mycelium thin for resource exploration B: Resource durability Short-lived resources (e.g., dung or rotting fruit) Fast mycelial growth for resource capture and then one-time reproduction after resource capture ("bang-bang life-history")semelparous life style Long-lived resources (e.g., dead tree) Slower growth and late reproduction start, with multiple reproductive periods -iteroparous life style C: Presence of competition No interaction between individuals Grow fast to monopolize resources Metabolic interactions between individuals Engage in cross-feeding or interference competition D: Conditions causing positive, negative or no MGR-spore yield correlation Novel condition causing low fitness No tradeoff, growth rate and reproduction may be positively correlated and both may improve adaptively Condition to which the fungus is relatively well adapted Tradeoff between growth rate and reproduction may be apparent and constrain further adaptation Table 1.1: Overview of the various life-history options that a fungus may adopt based on environmental conditions. (A) Resource quality, (B) Resource durability, (C) Presence of multiple individuals. (D) Describes general conditions for a tradeoff between mycelial growth rate and asexual spore yield. The alternate strategies mentioned in (A-C) are not necessarily mutually exclusive and most fungi are likely to employ a combination of these strategies based on ecology and organismal biology.

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“…As observed from different studies optimal production requires a distinct morphology which is likely to be process specific. Interesting attempts have employed targeted metabolic engineering (McIntyre et al, 2001a; Müller et al, 2002; Thykaer et al, 2009), evolutive adaptation in chemostat (van de Vondervoort et al, 2004) or variation of operational parameters (Moreira et al, 1996; Spohr et al, 1998; Xu et al, 2000) to influence the morphology in filamentous microorganisms. However, the whole picture is quite complex.…”

Section: Introductionmentioning

confidence: 99%

Improved enzyme production by bio‐pellets of Aspergillus niger: Targeted morphology engineering using titanate microparticles

Driouch

Hänsch

Wucherpfennig

et al. 2011

Biotech & Bioengineering

147

142

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The present study describes the design of bio-pellet morphologies of the industrial working horse Aspergillus niger strains in submerged culture. The novel approach recruits the intended addition of titanate microparticles (TiSiO(4), 8 µm) to the growth medium. As tested for two recombinant strains producing fructofuranosidase and glucoamylase, the enzyme titer by the titanate-enhanced cultures in shake flasks was increased 3.7-fold to 150 U/mL (for fructofuranosidase) and 9.5-fold to 190 U/mL (for glucoamylase) as compared to the control. This could be successfully utilized for improved enzyme production in stirred tank reactors. Stimulated by the particles, the achieved final glucoamylase activity of 1,080 U/mL (fed-batch) and 320 U/mL (batch) was sevenfold higher as compared to the conventional processes. The major reason for the enhanced production was the close association between the titanate particles and the fungal cells. Already below 2.5 g/L the micromaterial was found inside the pellets, including single particles embedded as 50-150 µm particle aggregates in the center resulting in core shell pellets. With increasing titanate levels the pellet size decreased from 1,700 µm (control) to 300 µm. Fluorescence based resolution of GFP expression revealed that the large pellets of the control were only active in a 200 µm surface layer. This matches with the critical penetration depth for nutrients and oxygen typically observed for fungal pellets. The biomass within the titanate derived fungal pellets, however, was completely active. This was due a reduced thickness of the biomass layer via smaller pellets as well as the core shell structure. Moreover, also the created loose inner pellet structure enabled a higher mass transfer and penetration depths for up to 500 µm. The creation of core-shell pellets has not been achieved previously by the addition of microparticles, for example, made of talc or alumina. Due to this, the present work opens further possibilities to use microparticles for tailor-made morphology design of filamentous fungi, especially for pellet based processes which have a long and strong industrial relevance for industrial production.

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Isolation of a fluffy mutant of Aspergillus niger from chemostat culture and its potential use as a morphologically stable host for protein production

Cited by 6 publications

References 36 publications

The Evolution of Sex: a Perspective from the Fungal Kingdom

The Evolution of Sex: a Perspective from the Fungal Kingdom

The role of tradeoffs among life-history traits in a filamentous fungus

Improved enzyme production by bio‐pellets of Aspergillus niger: Targeted morphology engineering using titanate microparticles

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