Relation between pellet fragmentation kinetics and cellulolytic enzymes production by Aspergillus niger in conventional bioreactor with different impellers

Buffo, Mariane Molina; Esperança, Mateus N.; Farinas, Cristiane S.; Badino, Alberto Colli

doi:10.1016/j.enzmictec.2020.109587

Cited by 16 publications

(9 citation statements)

References 36 publications

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“…Figure 2d shows a DIC image of a pellet, which has broken at its spore core and two exemplary stereomicroscopic images with broken pellets at 48 h of cultivation. Buffo et al (2020) observed the breakage of pellets into large pellet fragments with sizes between 200 and 500 µm during A. niger bioreactor cultivations. Pictures in their publication show these fragments breaking out of central pellet parts.…”

Section: Resultsmentioning

confidence: 99%

From spores to fungal pellets: A new high‐throughput image analysis highlights the structural development of Aspergillus niger

Müller

Barthel

Schmideder

et al. 2022

Biotech & Bioengineering

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Many filamentous fungi are exploited as cell factories in biotechnology. Cultivated under industrially relevant submerged conditions, filamentous fungi can adopt different macromorphologies ranging from dispersed mycelia over loose clumps to pellets. Central to the development of a pellet morphology is the agglomeration of spores after inoculation followed by spore germination and outgrowth into a pellet population, which is usually very heterogeneous. As the dynamics underlying population heterogeneity is not yet fully understood, we present here a new high‐throughput image analysis pipeline based on stereomicroscopy to comprehensively assess the developmental program starting from germination up to pellet formation. To demonstrate the potential of this pipeline, we used data from 44 sampling times harvested during a 48 h submerged batch cultivation of the fungal cell factory Aspergillus niger. The analysis of up to 1700 spore agglomerates and 1500 pellets per sampling time allowed the precise tracking of the morphological development of the overall culture. The data gained were used to calculate size distributions and area fractions of spores, spore agglomerates, spore agglomerates within pellets, pellets, and dispersed mycelia. This approach eventually enables the quantification of culture heterogeneities and pellet breakage.

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Section: Resultsmentioning

confidence: 99%

From spores to fungal pellets: A new high‐throughput image analysis highlights the structural development of Aspergillus niger

Müller

Barthel

Schmideder

et al. 2022

Biotech & Bioengineering

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“…As mentioned, the shear forces imposed to the microorganism also act as a controlling parameter of fungi morphology . In stirred-tank bioreactors, hyphal breakage is likely to occur near the impeller tips.…”

Section: Resultsmentioning

confidence: 99%

“…As mentioned, the shear forces imposed to the microorganism also act as a controlling parameter of fungi morphology. 50 In stirred-tank bioreactors, hyphal breakage is likely to occur near the impeller tips. As RT impellers determine higher shear rates on the tip of impeller, the fluid rheology in these regions is usually different to the areas near the bioreactor walls, where the shear forces are weaker.…”

Section: Constant Airflow Experimentsmentioning

confidence: 99%

Improving the Environmental Sustainability of Polyketides Colorants Production by Talaromyces Strain through Better Hydrodynamic Design in Bioreactors

Oliveira

Zapata-Boada

Silva

et al. 2022

ACS Sustainable Chem. Eng.

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One important step toward the commercialization of microbial-derived colorants is the reproducibility of the cultivation stage in bench-scale bioreactors as well as improving the hydrodynamic design in bioreactors. Aiming to address these technical barriers, Talaromyces amestolkiae was cultivated in a 4 L stirred-tank bioreactor using two types of impellers (Rushton turbine (RT) and Elephant ear (EE) impellers) and aeration modes (cascading and constant airflow) to assess their effects on red colorant production. The results showed that EE under constant airflow (4.0 L min–1) promoted the maximum red colorant formation (28.7 UA500nm), thus improving the reproducibility of the process. The volumetric oxygen transfer coefficient of culture broth was correlated to cell morphology, which was a result of the impeller geometry of EE through the shear conditions impacting the fungi cells. The hairy pellet morphology favored nutrient and oxygen uptake and allowed an improvement in the colorant’s synthesis. Life cycle assessment was also carried out to identify opportunities for improving the best process design from an environmental sustainability perspective. For example, the total climate change and primary energy demand were estimated at 31.11 kg CO2 eq./g red colorant and 830.7 MJ/g red colorant, respectively, with the cultivation stage contributing with 65 and 63% of these impacts. The electricity consumption was identified as the main hotspot in this stage, a trend that was observed across all other impact categories. This can be improved by optimizing cultivation lengths combined with the use of low carbon electricity sources. These findings ensure a step forward toward the scaling-up at the industrial scale of the T. amestolkiae cultivation for the production of bio-based colorants in an environmentally sustainable way.

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“…In the nemadectin fermentation process, Wang et al found that the radial-axial impeller combination with a time average velocity of 0.38-0.54 U tip was more beneficial for the activity of Streptomyces cyaneogriseus ssp. noncyanogenus and nemadectin biosynthesis than other combinations [18].In addition, the properties of the fermentation broth and microbial morphology, which greatly influence fermentation, are affected by the impeller type [19,20]. Li et al showed that the hyphal morphology was related to the hydrodynamic stress and hyphal tensile strength [21].…”

mentioning

confidence: 99%

“…In addition, the properties of the fermentation broth and microbial morphology, which greatly influence fermentation, are affected by the impeller type [19,20]. Li et al showed that the hyphal morphology was related to the hydrodynamic stress and hyphal tensile strength [21].…”

mentioning

confidence: 99%

Effects of Impeller Geometry on the 11α-Hydroxylation of Canrenone in Rushton Turbine-Stirred Tanks

Rong

Tang

Guan

et al. 2021

J. Microbiol. Biotechnol.

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The steroid compound 11α-hydroxycanrenone is an important intermediate for the synthesis of the antihypertensive drug eplerenone, which can be obtained by 11α-hydroxylation of canrenone [1]. Studies have revealed that biotransformation is a common method for the synthesis of steroid hormone drug intermediates [2,3]. For example, Aspergillus spp. and Rhizopus spp. are frequently used for the 11α-hydroxylation of canrenone, in which cytochromes P450 (P450s) are the key to bioconversion [4,5]. P450s belong to the group of external monooxygenases, and the supply of oxygen is the basic requirement for the 11α-hydroxylation of canrenone [6].It is known that aerobic fermentation is affected by the type and geometry of the impeller in stirred tanks [7][8][9]. The gas dispersion, flow pattern and mixing in bioreactors are all affected by these factors. The gas distribution has a great influence on the dissolved oxygen (DO) content in fermentation broth [10,11]. Shin et al. indicated that the oxygen supply of fermentation broth, which was the restrictive factor for enzyme production by Aspergillus oryzae, was affected by impeller geometries [12]. The growth of microorganisms and the expression of enzymes in fermentation were also affected by DO [13,14]. Regarding the flow pattern and mixing, it is known that in submerged fermentation, the product quality is affected by these factors [15,16]. Li et al. found that mixing was improved by increasing the impeller diameter by approximately 10% in the enzyme production of A. oryzae fermentation [17]. In the nemadectin fermentation process, Wang et al. found that the radial-axial impeller combination with a time average velocity of 0.38-0.54 U tip was more beneficial for the activity of Streptomyces cyaneogriseus ssp. noncyanogenus and nemadectin biosynthesis than other combinations [18].In addition, the properties of the fermentation broth and microbial morphology, which greatly influence fermentation, are affected by the impeller type [19,20]. Li et al. showed that the hyphal morphology was related to the hydrodynamic stress and hyphal tensile strength [21]. There is also a correlation between the hydrodynamic stresses and impeller types. Ghobadi et al. increased the pellet porosity during mixing via a flexible shaft agitator, The 11α-hydroxylation of canrenone can be catalyzed by Aspergillus ochraceus in bioreactors, where the geometry of the impeller greatly influences the biotransformation. In this study, the effects of the blade number and impeller diameter of a Rushton turbine on the 11α-hydroxylation of canrenone were considered. The results of fermentation experiments using a 50 mm four-blade impeller showed that 3.40% and 11.43% increases in the conversion ratio were achieved by increasing the blade number and impeller diameter, respectively. However, with an impeller diameter of 60 mm, the conversion ratio with a six-blade impeller was 14.42% lower than that with a four-blade impeller. Data from cold model experiments with a large-diameter six-blade impeller indicated t...

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Relation between pellet fragmentation kinetics and cellulolytic enzymes production by Aspergillus niger in conventional bioreactor with different impellers

Cited by 16 publications

References 36 publications

From spores to fungal pellets: A new high‐throughput image analysis highlights the structural development of Aspergillus niger

From spores to fungal pellets: A new high‐throughput image analysis highlights the structural development of Aspergillus niger

Improving the Environmental Sustainability of Polyketides Colorants Production by Talaromyces Strain through Better Hydrodynamic Design in Bioreactors

Effects of Impeller Geometry on the 11α-Hydroxylation of Canrenone in Rushton Turbine-Stirred Tanks

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