Adaptation of Aspergillus niger to short-term salt strees

Park, Jong Chul; Nemoto, Yasuyuki; Homma, Toshiyuki; Jing, Weimin; Chen, Yuansong; Matsuoka, Hiroaki; Ohno, Harumi; Takatori, Kosuke; Kurata, Hiroshi

doi:10.1007/bf00170399

Cited by 15 publications

(6 citation statements)

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“…Such morphological response has been previously described in literature [ 39 ] and is therefore unlikely to be limited to the investigated Aspergillus strains. Park et al were able to show an influence of elevated salt concentrations on A. niger morphology, as sodium chloride caused the swelling of the hyphal tip and branch formation within the swollen region [ 43 , 44 ]. In a study of Kim et al, however, potassium chloride, up to a concentration of 1 M had no effect on morphology of Aspergillus nidulans [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

Morphology engineering - Osmolality and its effect on Aspergillus niger morphology and productivity

2011

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BackgroundThe filamentous fungus Aspergillus niger is a widely used strain in a broad range of industrial processes from food to pharmaceutical industry. One of the most intriguing and often uncontrollable characteristics of this filamentous organism is its complex morphology, ranging from dense spherical pellets to viscous mycelia depending on culture conditions. Optimal productivity correlates strongly with a specific morphological form, thus making high demands on process control.ResultsIn about 50 2L stirred tank cultivations the influence of osmolality on A. niger morphology and productivity was investigated. The specific productivity of fructofuranosidase producing strain A. niger SKAn 1015 could be increased notably from 0.5 to 9 U mg-1 h-1 around eighteen fold, by increasing the culture broth osmolality by addition of sodium chloride. The specific productivity of glucoamylase producing strain A. niger AB1.13, could be elevated using the same procedure. An optimal producing osmolality was shown to exist well over the standard osmolality at about 3.2 osmol kg-1 depending on the strain. Fungal morphology of all cultivations was examined by microscope and characterized by digital image analysis. Particle shape parameters were combined to a dimensionless Morphology number, which enabled a comprehensive characterization of fungal morphology correlating closely with productivity. A novel method for determination of germination time in submerged cultivations by laser diffraction, introduced in this study, revealed a decelerated germination process with increasing osmolality.ConclusionsThrough the introduction of the versatile Morphology number, this study provides the means for a desirable characterization of fungal morphology and demonstrates its relation to productivity. Furthermore, osmolality as a fairly new parameter in process engineering is introduced and found to affect fungal morphology and productivity. Osmolality might provide an auspicious and reliable approach to increase the productivity in industrial processes. Because of the predictable behavior fungal morphology showed in dependence of osmolality, a customization of morphology for process needs seems feasible.

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Section: Resultsmentioning

confidence: 99%

Morphology engineering - Osmolality and its effect on Aspergillus niger morphology and productivity

2011

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“…As noted in Table 1, a water potential of À3.4 MPa is approximately a third of that used in several previous studies (Charlang and Horowitz, 1971;Park et al, 1993;Redkar et al, 1998). Furthermore, unlike previous studies where Aspergilli were exposed to a high concentration of external osmolyte for a short period of time (Han and Prade, 2002;Park et al, 1993;Redkar et al, 1998), we studied the effect of a moderate concentration of osmolyte for an extended period. Therefore, we use the term 'osmoadaptation' instead of 'osmotic stress' (Hohmann, 2002) to characterize conditions used here.…”

Section: Increased Water Potential (W) and Its Effect On Macroand Micmentioning

confidence: 90%

“…A number of previous studies have focused on osmoadaptation in filamentous fungi (Avenot et al, 2005;Beever and Laracy, 1986;Horowitz, 1971, 1974;de Vries et al, 2003;Hefnawy, 2001;Kawasaki et al, 2002;Mizutani et al, 2004;Park et al, 1993;Redkar et al, 1998Redkar et al, , 1996Redkar et al, , 1995Seidl et al, 2004;Takeshita et al, 2002;Yoshimi et al, 2004), which has been found to have many similarities with osmoadaptation in yeast (recently reviewed in (Hohmann, 2002)). However, these fungal studies typically provide gene-specific insights rather than a systematic or global perspective of osmoadaptation.…”

Section: Introductionmentioning

confidence: 92%

Proteome map of Aspergillus nidulans during osmoadaptation

Kim

Nandakumar

Marten

2007

Fungal Genetics and Biology

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“…For this purpose, the flow‐through chamber is a good tool for examining mycelial growth kinetics, particularly in submerged culture. Previous experiments were carried out using well‐known industrial microorganisms, such as Streptomyces tendae (Reichl, King, and Gilles 1992; Treskatis et al 1996), Aspergillus niger (Park et al 1993), and A. oryzae (Spohr et al 1998).…”

Section: Discussionmentioning

confidence: 99%

Analysis of Morphological Relationship Between Micro‐ and Macromorphology of Mortierella Species Using a Flow‐Through Chamber Coupled with Image Analysis

Park

Koizumi

Higashiyama

2006

J Eukaryotic Microbiology

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Using a flow-through chamber coupled with image analysis, the morphological parameters of 11 Mortierella species were quantified, and the relationship between micro- and macromorphology was investigated. On potato-dextrose-agar plates, 5 species formed rose petal-like colonies, 3 formed large round colonies, and 3 formed donut-like colonies. By observing micromorphology in a flow-through chamber, fungi were divided into 3 groups, classified according to morphological parameters: (i) a group with a high branch formation rate (q(b): tip/microm/h) and a low tip extension rate (q(tip): microm/tip/h); (ii) a group with a low branch formation rate and a high tip extension rate; and (iii) a group intermediate between the former and the latter groups. In suspension culture, group (i) fungi formed a hyphal bundle with a pulpy pellet-like morphology and a pellet core. In contrast, group (ii) fungi showed an aggregation of hyphae without the pellet core. In a narrow-specific hyphal growth rate (mu(l)) range (0.35-0.45 h(-1)), a higher branch formation rate led to increased hyphal branching, resulting in the formation of a hyphal bundle with a pulpy pellet-like morphology and a pellet core. When the branch formation rate was lower than 2 x 10(-3) tips/microm/h, the mycelia formed less branched but longer hypha. Our study surmises that a micromorphology consisting of a high hyphal growth rate (0.4 h(-1)), low tip extension rate (20 tips/microm/h), and high branch formation rate (8 x 10(-3) tips/microm/h) forms the suitable macromorphology for arachidonic acid production.

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Adaptation of Aspergillus niger to short-term salt strees

Cited by 15 publications

References 15 publications

Morphology engineering - Osmolality and its effect on Aspergillus niger morphology and productivity

Morphology engineering - Osmolality and its effect on Aspergillus niger morphology and productivity

Proteome map of Aspergillus nidulans during osmoadaptation

Analysis of Morphological Relationship Between Micro‐ and Macromorphology of Mortierella Species Using a Flow‐Through Chamber Coupled with Image Analysis

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