scholarly journals Key Process Conditions for Production of C4 Dicarboxylic Acids in Bioreactor Batch Cultures of an Engineered Saccharomyces cerevisiae Strain

2009 ◽  
Vol 76 (3) ◽  
pp. 744-750 ◽  
Author(s):  
Rintze M. Zelle ◽  
Erik de Hulster ◽  
Wendy Kloezen ◽  
Jack T. Pronk ◽  
Antonius J. A. van Maris
Keyword(s):  
Carbon Dioxide ◽  
Saccharomyces Cerevisiae ◽  
Process Parameters ◽  
Malic Acid ◽  
Acid Production ◽  
Shake Flask ◽  
Simultaneous Optimization ◽  
Process Conditions ◽  
Recent Effort ◽  
Shake Flasks

ABSTRACT A recent effort to improve malic acid production by Saccharomyces cerevisiae by means of metabolic engineering resulted in a strain that produced up to 59 g liter−1 of malate at a yield of 0.42 mol (mol glucose)−1 in calcium carbonate-buffered shake flask cultures. With shake flasks, process parameters that are important for scaling up this process cannot be controlled independently. In this study, growth and product formation by the engineered strain were studied in bioreactors in order to separately analyze the effects of pH, calcium, and carbon dioxide and oxygen availability. A near-neutral pH, which in shake flasks was achieved by adding CaCO3, was required for efficient C4 dicarboxylic acid production. Increased calcium concentrations, a side effect of CaCO3 dissolution, had a small positive effect on malate formation. Carbon dioxide enrichment of the sparging gas (up to 15% [vol/vol]) improved production of both malate and succinate. At higher concentrations, succinate titers further increased, reaching 0.29 mol (mol glucose)−1, whereas malate formation strongly decreased. Although fully aerobic conditions could be achieved, it was found that moderate oxygen limitation benefitted malate production. In conclusion, malic acid production with the engineered S. cerevisiae strain could be successfully transferred from shake flasks to 1-liter batch bioreactors by simultaneous optimization of four process parameters (pH and concentrations of CO2, calcium, and O2). Under optimized conditions, a malate yield of 0.48 ± 0.01 mol (mol glucose)−1 was obtained in bioreactors, a 19% increase over yields in shake flask experiments.

scholarly journals Optimization of Pre-Inoculum, Fermentation Process Parameters and Precursor Supplementation Conditions to Enhance Apigenin Production by a Recombinant Streptomyces albus Strain

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 161
Author(s):  
Simona Barbuto Ferraiuolo ◽  
Odile Francesca Restaino ◽  
Ignacio Gutiérrez-del-Río ◽  
Riccardo Ventriglia ◽  
Marcella Cammarota ◽  
...  
Keyword(s):  
Process Parameters ◽  
Batch Fermentation ◽  
Recombinant Strain ◽  
Fermentation Process ◽  
Shake Flask ◽  
Process Conditions ◽  
Streptomyces Albus ◽  
Shake Flasks ◽  
Optimization Of Fermentation ◽  
Streptomyces Albus J1074

Streptomyces albus J1074-pAPI (Streptomyces albus-pAPI) is a recombinant strain constructed to biotechnologically produce apigenin, a flavonoid with interesting bioactive features that up to now has been manufactured by extraction from plants with long and not environmentally friendly procedures. So far, in literature, only a maximum apigenin concentration of 80.0 µg·L−1 has been obtained in shake flasks. In this paper, three integrated fermentation strategies were exploited to enhance the apigenin production by Streptomyces albus J1074-pAPI, combining specific approaches for pre-inoculum conditions, optimization of fermentation process parameters and supplementation of precursors. Using a pre-inoculum of mycelium, the apigenin concentration increased of 1.8-fold in shake flask physiological studies. In 2L batch fermentation, the aeration and stirring conditions were optimized and integrated with the new inoculum approach and the apigenin production reached 184.8 ± 4.0 µg·L−1, with a productivity of 2.6 ± 0.1 μg·L−1·h−1. The supplementation of 1.5 mM L-tyrosine in batch fermentations allowed to obtain an apigenin production of 343.3 ± 3.0 µg·L−1 in only 48 h, with an increased productivity of 7.1 ± 0.1 μg·L−1·h−1. This work demonstrates that the optimization of fermentation process conditions is a crucial requirement to increase the apigenin concentration and productivity by up to 4.3- and 10.7-fold.

Characteristics of the high malic acid production mechanism in Saccharomyces cerevisiae sake yeast strain No. 28

2012 ◽  
Vol 114 (3) ◽  
pp. 281-285 ◽  
Author(s):  
Shunichi Nakayama ◽  
Ken Tabata ◽  
Takahiro Oba ◽  
Kenichi Kusumoto ◽  
Shinji Mitsuiki ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Malic Acid ◽  
Yeast Strain ◽  
Acid Production ◽  
Production Mechanism

scholarly journals Controlling Foam Morphology of Poly(methyl methacrylate) via Surface Chemistry and Concentration of Silica Nanoparticles and Supercritical Carbon Dioxide Process Parameters

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Deniz Rende ◽  
Linda S. Schadler ◽  
Rahmi Ozisik
Keyword(s):  
Carbon Dioxide ◽  
Surface Modification ◽  
Supercritical Carbon Dioxide ◽  
Surface Chemistry ◽  
Silica Nanoparticles ◽  
Process Parameters ◽  
Process Conditions ◽  
Average Cell ◽  
Foam Morphology ◽  
Supercritical Carbon

Polymer nanocomposite foams have received considerable attention because of their potential use in advanced applications such as bone scaffolds, food packaging, and transportation materials due to their low density and enhanced mechanical, thermal, and electrical properties compared to traditional polymer foams. In this study, silica nanofillers were used as nucleating agents and supercritical carbon dioxide as the foaming agent. The use of nanofillers provides an interface upon which CO2nucleates and leads to remarkably low average cell sizes while improving cell density (number of cells per unit volume). In this study, the effect of concentration, the extent of surface modification of silica nanofillers with CO2-philic chemical groups, and supercritical carbon dioxide process conditions on the foam morphology of poly(methyl methacrylate), PMMA, were systematically investigated to shed light on the relative importance of material and process parameters. The silica nanoparticles were chemically modified with tridecafluoro-1,1,2,2-tetrahydrooctyl triethoxysilane leading to three different surface chemistries. The silica concentration was varied from 0.85 to 3.2% (by weight). The supercritical CO2foaming was performed at four different temperatures (40, 65, 75, and 85°C) and between 8.97 and 17.93 MPa. By altering the surface chemistry of the silica nanofiller and manipulating the process conditions, the average cell diameter was decreased from9.62±5.22to1.06±0.32 μm, whereas, the cell density was increased from7.5±0.5×108to4.8±0.3×1011cells/cm3. Our findings indicate that surface modification of silica nanoparticles with CO2-philic surfactants has the strongest effect on foam morphology.

L-malic acid production using immobilized saccharomyces cerevisiae

1991 ◽  
Vol 30 (2) ◽  
pp. 217-224 ◽  
Author(s):  
Z. M. B. Figueiredo ◽  
L. B. Carvalho
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Malic Acid ◽  
Acid Production

L‐malic acid production from xylose by engineered Saccharomyces cerevisiae

2021 ◽  
pp. 2000431
Author(s):  
Nam Kyu Kang ◽  
Jae Won Lee ◽  
Donald R. Ort ◽  
Yong‐Su Jin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Malic Acid ◽  
Acid Production ◽  
Engineered Saccharomyces Cerevisiae

Malic acid production and consumption by selected of Saccharomyces cerevisiae under anaerobic and aerobic conditions

1984 ◽  
Vol 19 (6) ◽  
pp. 427-429 ◽  
Author(s):  
Fabrizio Fatichenti ◽  
Giovanni Antonio Farris ◽  
Pietrino Deiana ◽  
Salvatore Ceccarelli
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Malic Acid ◽  
Acid Production ◽  
Aerobic Conditions ◽  
Production And Consumption

l-Malic acid production from fumaric acid by a laboratory Saccharomyces cerevisiae strain SHY2

1996 ◽  
Vol 18 (12) ◽  
pp. 1441-1446 ◽  
Author(s):  
Xiaohai Wang ◽  
C. S. Gong ◽  
George T. Tsao
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fumaric Acid ◽  
Malic Acid ◽  
Acid Production

scholarly journals Immobilization of Aspergillus oryzae DSM 1863 for l-Malic Acid Production

Fermentation ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 26
Author(s):  
Aline Kövilein ◽  
Vera Aschmann ◽  
Silja Hohmann ◽  
Katrin Ochsenreither
Keyword(s):  
Aspergillus Oryzae ◽  
Malic Acid ◽  
Acid Production ◽  
Carbon Sources ◽  
Cell Immobilization ◽  
Batch Processes ◽  
Natural Polymers ◽  
Biomass Retention ◽  
Shake Flasks ◽  
Acetate Medium

Whole-cell immobilization by entrapment in natural polymers can be a tool for morphological control and facilitate biomass retention. In this study, the possibility of immobilizing the filamentous fungus Aspergillus oryzae for l-malic acid production was evaluated with the two carbon sources acetate and glucose. A. oryzae conidia were entrapped in alginate, agar, and κ-carrageenan and production was monitored in batch processes in shake flasks and 2.5-L bioreactors. With glucose, the malic acid concentration after 144 h of cultivation using immobilized particles was mostly similar to the control with free biomass. In acetate medium, production with immobilized conidia of A. oryzae in shake flasks was delayed and titers were generally lower compared to cultures with free mycelium. While all immobilization matrices were stable in glucose medium, disintegration of bead material and biomass detachment in acetate medium was observed in later stages of the fermentation. Still, immobilization proved advantageous in bioreactor cultivations with acetate and resulted in increased malic acid titers. This study is the first to evaluate immobilization of A. oryzae for malic acid production and describes the potential but also challenges regarding the application of different matrices in glucose and acetate media.

scholarly journals Analysis and optimization of laser drilling process during machining of AISI 303 material using grey relational analysis approach

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
V. Chengal Reddy ◽  
Thota Keerthi ◽  
T. Nishkala ◽  
G. Maruthi Prasad Yadav
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Grey Relational Analysis ◽  
Pulse Frequency ◽  
Laser Drilling ◽  
Simultaneous Optimization ◽  
Fibre Laser ◽  
Drilling Process ◽  
Relational Analysis ◽  
Grey Relational

AbstractSurface roughness and heat-affected zone (HAZ) are the important features which influence the performance of the laser-drilled products. Understanding the influence of laser process parameters on these responses and identifying the cutting conditions for simultaneous optimization of these responses are a primary requirement in order to improve the laser drilling performance. Nevertheless, no such contribution has been made in the literature during laser drilling of AISI 303 material. The aim of the present work is to optimize the surface roughness (Ra) and HAZ in fibre laser drilling of AISI 303 material using Taguchi-based grey relational analysis (GRA). From the GRA methodology, the recommended optimum combination of process parameters is flushing pressure at 30 Pa, laser power at 2000 W and pulse frequency at 1500 Hz for simultaneous optimization of Ra and HAZ, respectively. From analysis of variance, the pulse frequency is identified as the most influenced process parameters on laser drilling process performance.

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