Intrinsic kinetic parameters of the pellet forming fungusAspergillus awamori

Hellendoorn, L.; Mulder, H.; Heuvel, JC van den; Ottengraf, Spp Simon

doi:10.1002/(sici)1097-0290(19980605)58:5<478::aid-bit3>3.0.co;2-a

Cited by 25 publications

(4 citation statements)

References 16 publications

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“…It was observed that within the ranges evaluated, the higher the C/N ratio, the faster the kinetics, evidenced by the specific growth rate ( μ ) and the doubling time ( t d ), as shown in Table 2. The specific growth rates observed (0.02–0.15 h −1 ) were lower than those reported by Hellendoorn et al [31] (0.28–0.40 h −1 ) for cultivation of A. awamori in an airlift reactor, and this could be possibly due to oxygen transfer limitations in the shaken-flask cultures.…”

Section: Resultscontrasting

confidence: 76%

Multiresponse Optimization of Inoculum Conditions for the Production of Amylases and Proteases by Aspergillus awamori in Solid-State Fermentation of Babassu Cake

et al. 2011

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This work aimed at investigating the simultaneous production of amylases and proteases by solid-state fermentation (SSF) of babassu cake using Aspergillus awamori IOC-3914. By means of experimental design techniques and the desirability function, optimum inoculum conditions (C/N ratio of propagation medium, inoculum age, and concentration of inoculum added to SSF medium) for the production of both groups of enzymes were found to be 25.8, 28.4 h, and 9.1 mg g−1, respectively. Significant influence of both initial C/N ratio and inoculum concentration was observed. Optimum amylolytic activities predicted by this multiresponse analysis were validated by independent experiments, thus indicating the efficacy of this approach.

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Section: Resultscontrasting

confidence: 76%

Multiresponse Optimization of Inoculum Conditions for the Production of Amylases and Proteases by Aspergillus awamori in Solid-State Fermentation of Babassu Cake

et al. 2011

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“…Exponential growth phase was very short and lasted not more than 12 h and it was the time, when pellets were extremely small. Their diameter was lower than 500 μm [19]. In the present experiments, although exponential growth phase must have occurred, only distinct linear biomass growth is seen in Fig.…”

Section: Resultsmentioning

confidence: 61%

“…Cui et al [18] modelled A. awamori growth taking diffusion, shaving intensity (changes of fungal morphology) and autolysis rate of biomass into account. Hellendoorn et al [19] measured oxygen concentration profiles in natural and artificial (made of agar) pellets of A. awamori and performed the advanced mathematical modelling of their growth including the determination of Thiele number. Also, Michel et al [20] made measurements of oxygen level together with the mathematical description of oxygen transfer in the fungal pellets but in this case they worked with a lignin degrading basidiomycete Phanerochaete chrysosporium .…”

Section: Introductionmentioning

confidence: 99%

Influence of oxygen on lovastatin biosynthesis by Aspergillus terreus ATCC 20542 quantitatively studied on the level of individual pellets

Bizukojć

Gonciarz

2015

Bioprocess Biosyst Eng

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Despite oxygen is believed to be the most important environmental factor for any aerobic microbial process, the quantitative studies of its influence on growth and metabolite formation on the level of individual pellets formed by filamentous fungi were seldom performed. Never was it made for lovastatin producer Aspergillus terreus ATCC20542. Thus, this work is a quantitative study of oxygen transfer into A. terreus pellets during lovastatin biosynthesis in the shake flask culture. The basic measurement tool was an oxygen microprobe allowing for obtaining oxygen concentration profiles in the pellets. The pellets of various sizes from 1,600 to 6,400 μm exerting different oxygen transfer conditions were studied. Also various initial concentrations of carbon source were applied to change the conditions of biological reaction running in the pellets. Effective diffusivities in A. terreus pellets ranged from 643 to 1,342 μm s−1 dependent on their size and structure. It occurred that only the smallest pellets of diameter equal to about 1,400 μm were fully penetrated by oxygen. What is more, apart from the size of pellets, the appropriate lactose concentration was required to effectively produce lovastatin. Its value was correlated with oxygen concentration on the surface of the pellet and could not be either too high, as the aforementioned oxygen level tended then to zero, or too low, as despite high oxygen concentration no biological reaction ran in the pellet and no lovastatin was formed.

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“…As observed for different filamentous fungi, a smaller pellet size is favorable in terms of nutrient and oxygen supply [8,[42][43][44][45]. Substrate consumption leads to an increased biomass density and thereby reduces the penetration depths of substrates in the pellets [46][47][48]. The oxygen transfer into a pellet was investigated in detail for Aspergillus niger.…”

Section: Plos Onementioning

confidence: 97%

Morphological and physiological characterization of filamentous Lentzea aerocolonigenes: Comparison of biopellets by microscopy and flow cytometry

et al. 2020

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Cell morphology of filamentous microorganisms is highly interesting during cultivations as it is often linked to productivity and can be influenced by process conditions. Hence, the characterization of cell morphology is of major importance to improve the understanding of industrial processes with filamentous microorganisms. For this purpose, reliable and robust methods are necessary. In this study, pellet morphology and physiology of the rebeccamycin producing filamentous actinomycete Lentzea aerocolonigenes were investigated by microscopy and flow cytometry. Both methods were compared regarding their applicability. To achieve different morphologies, a cultivation with glass bead addition (Ø = 969 μm, 100 g L-1) was compared to an unsupplemented cultivation. This led to two different macro-morphologies. Furthermore, glass bead addition increased rebeccamycin titers after 10 days of cultivation (95 mg L-1 with glass beads, 38 mg L-1 without glass beads). Macro-morphology and viability were investigated through microscopy and flow cytometry. For viability assessment fluorescent staining was used additionally. Smaller, more regular pellets were found for glass bead addition. Pellet diameters resulting from microscopy followed by image analysis were 172 μm without and 106 μm with glass beads, diameters from flow cytometry were 170 and 100 μm, respectively. These results show excellent agreement of both methods, each considering several thousand pellets. Furthermore, the pellet viability obtained from both methods suggested an enhanced metabolic activity in glass bead treated pellets during the exponential production phase. However, total viability values differ for flow cytometry (0.32 without and 0.41 with glass beads) and confocal laser scanning microscopy of single stained pellet slices (life ratio in production phase of 0.10 without and 0.22 with glass beads), which is probably caused by the different numbers of investigated pellets. In confocal laser scanning microscopy only one pellet per sample could be investigated while flow

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Intrinsic kinetic parameters of the pellet forming fungusAspergillus awamori

Cited by 25 publications

References 16 publications

Multiresponse Optimization of Inoculum Conditions for the Production of Amylases and Proteases by Aspergillus awamori in Solid-State Fermentation of Babassu Cake

Multiresponse Optimization of Inoculum Conditions for the Production of Amylases and Proteases by Aspergillus awamori in Solid-State Fermentation of Babassu Cake

Influence of oxygen on lovastatin biosynthesis by Aspergillus terreus ATCC 20542 quantitatively studied on the level of individual pellets

Morphological and physiological characterization of filamentous Lentzea aerocolonigenes: Comparison of biopellets by microscopy and flow cytometry

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