Pulsed Feeding during Fed-Batch Aspergillus oryzae Fermentation Leads to Improved Oxygen Mass Transfer

Bhargava, Swapnil; Wenger, Kevin S.; Marten, Mark R.

doi:10.1021/bp025694p

Cited by 25 publications

(17 citation statements)

References 18 publications

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“…Increased culture apparent viscosity and WCW were two critical variables affected by the scale up (Figures 2, 3, 4 and 5). High DCW and WCW biomasses have been shown to increase the culture apparent viscosity [24,25]. Also as the viscosity of viscous streptomycete fermentation increased, the oxygen transfer coefficient ( k L a ) was observed to decrease [26].…”

Section: Discussionmentioning

confidence: 99%

Exometabolome analysis reveals hypoxia at the up-scaling of a Saccharomyces cerevisiae high-cell density fed-batch biopharmaceutical process

Verderame

Leighton

et al. 2014

Microb Cell Fact

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BackgroundScale-up to industrial production level of a fermentation process occurs after optimization at small scale, a critical transition for successful technology transfer and commercialization of a product of interest. At the large scale a number of important bioprocess engineering problems arise that should be taken into account to match the values obtained at the small scale and achieve the highest productivity and quality possible. However, the changes of the host strain’s physiological and metabolic behavior in response to the scale transition are still not clear.ResultsHeterogeneity in substrate and oxygen distribution is an inherent factor at industrial scale (10,000 L) which affects the success of process up-scaling. To counteract these detrimental effects, changes in dissolved oxygen and pressure set points and addition of diluents were applied to 10,000 L scale to enable a successful process scale-up. A comprehensive semi-quantitative and time-dependent analysis of the exometabolome was performed to understand the impact of the scale-up on the metabolic/physiological behavior of the host microorganism. Intermediates from central carbon catabolism and mevalonate/ergosterol synthesis pathways were found to accumulate in both the 10 L and 10,000 L scale cultures in a time-dependent manner. Moreover, excreted metabolites analysis revealed that hypoxic conditions prevailed at the 10,000 L scale. The specific product yield increased at the 10,000 L scale, in spite of metabolic stress and catabolic-anabolic uncoupling unveiled by the decrease in biomass yield on consumed oxygen.ConclusionsAn optimized S. cerevisiae fermentation process was successfully scaled-up to an industrial scale bioreactor. The oxygen uptake rate (OUR) and overall growth profiles were matched between scales. The major remaining differences between scales were wet cell weight and culture apparent viscosity. The metabolic and physiological behavior of the host microorganism at the 10,000 L scale was investigated with exometabolomics, indicating that reduced oxygen availability affected oxidative phosphorylation cascading into down- and up-stream pathways producing overflow metabolism. Our study revealed striking metabolic and physiological changes in response to hypoxia exerted by industrial bioprocess up-scaling.

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Section: Discussionmentioning

confidence: 99%

Exometabolome analysis reveals hypoxia at the up-scaling of a Saccharomyces cerevisiae high-cell density fed-batch biopharmaceutical process

Verderame

Leighton

et al. 2014

Microb Cell Fact

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“…It is not clear how morphology exactly affects productivity. It has been proposed that this is due to the effect of the fungal morphology on the viscosity of the medium (Bhargava et al 2003). Viscosity correlates with the extent of dispersed growth; large micro-colonies thus result in a low viscosity.…”

Section: Vegetative Growthmentioning

confidence: 99%

Development in Aspergillus

Krijgsheld

Bleichrodt

Veluw

et al. 2013

Studies in Mycology

320

293

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The genus Aspergillus represents a diverse group of fungi that are among the most abundant fungi in the world. Germination of a spore can lead to a vegetative mycelium that colonizes a substrate. The hyphae within the mycelium are highly heterogeneous with respect to gene expression, growth, and secretion. Aspergilli can reproduce both asexually and sexually. To this end, conidiophores and ascocarps are produced that form conidia and ascospores, respectively. This review describes the molecular mechanisms underlying growth and development of Aspergillus.

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“…Pulsed addition of a limiting carbon source to reduce broth viscosity during heterologous protein expression has been studied thoroughly in fed-batch fermentation in bacteria, yeast, and in one filamentous fungus (A. oryzae [7][8][9][10]). In this paper, this technique was successfully applied in an A. niger fed-batch fermentation with excellent results.…”

Section: Discussionmentioning

confidence: 99%

Enzymatic resolution of racemic phenyloxirane by a novel epoxide hydrolase from Aspergillus niger SQ-6 and its fed-batch fermentation

Liu

Qian

et al. 2005

J IND MICROBIOL BIOTECHNOL

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A microorganism with the ability to catalyze the resolution of racemic phenyloxirane was isolated and identified as Aspergillus niger SQ-6. Chiral capillary electrophoresis was successfully applied to separate both phenyloxirane and phenylethanediol. The epoxide hydrolase (EH) involved in this resolution process was (R)-stereospecific and constitutively expressed. When whole cells were used during the biotransformation process, the optimum temperature and pH for stereospecific vicinal diol production were 35 degrees C and 7.0, respectively. After a 24-h conversion, the enantiomer excess of (R)-phenylethanediol produced was found to be >99%, with a conversion rate of 56%. In fed-batch fermentations at 30 degrees C for 44 h, glycerol (20 g L(-1)) and corn steep liquor (CSL) (30 g L(-1)) were chosen as the best initial carbon and nitrogen sources, and EH production was markedly improved by pulsed feeding of sucrose (2 g L(-1) h(-1)) and continuous feeding of CSL (1 g L(-1) h(-1)) at a fermentation time of 28 h. After optimization, the maximum dry cell weight achieved was 24.5+/-0.8 g L(-1); maximum EH production was 351.2+/-13.1 U L(-1) with a specific activity of 14.3+/-0.5 U g(-1). Partially purified EH exhibited a temperature optimum at 37 degrees C and pH optimum at 7.5 in 0.1 M phosphate buffer. This study presents the first evidence for the existence of a predicted epoxide racemase, which might be important in the synthesis of epoxide intermediates.

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Pulsed Feeding during Fed-Batch Aspergillus oryzae Fermentation Leads to Improved Oxygen Mass Transfer

Cited by 25 publications

References 18 publications

Exometabolome analysis reveals hypoxia at the up-scaling of a Saccharomyces cerevisiae high-cell density fed-batch biopharmaceutical process

Exometabolome analysis reveals hypoxia at the up-scaling of a Saccharomyces cerevisiae high-cell density fed-batch biopharmaceutical process

Development in Aspergillus

Enzymatic resolution of racemic phenyloxirane by a novel epoxide hydrolase from Aspergillus niger SQ-6 and its fed-batch fermentation

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