Effect of complex nitrogen source on the synthesis and accumulation of poly(3-hydroxybutyric acid) by recombinantEscherichia coli in flask and fed-batch cultures

1994 ◽  
Vol 2 (3) ◽  
pp. 169-176 ◽  
Author(s):  
Sang Yup Lee ◽  
Ho Nam Chang
Keyword(s):  
Nitrogen Source ◽  
Hydroxybutyric Acid ◽  
Fed Batch ◽  
Batch Cultures ◽  
Complex Nitrogen Source

scholarly journals Bacteriocin Production with Lactobacillus amylovorus DCE 471 Is Improved and Stabilized by Fed-Batch Fermentation

2000 ◽  
Vol 66 (2) ◽  
pp. 606-613 ◽  
Author(s):  
Raf Callewaert ◽  
Luc De Vuyst
Keyword(s):  
Lactic Acid ◽  
Nitrogen Source ◽  
Culture Conditions ◽  
Bacteriocin Production ◽  
Fed Batch ◽  
Batch Cultures ◽  
Lactobacillus Amylovorus ◽  
Complex Nitrogen Source ◽  
High Concentrations ◽  
Substrate Addition

ABSTRACT Amylovorin L471 is a small, heat-stable, and hydrophobic bacteriocin produced by Lactobacillus amylovorus DCE 471. The nutritional requirements for amylovorin L471 production were studied with fed-batch fermentations. A twofold increase in bacteriocin titer was obtained when substrate addition was controlled by the acidification rate of the culture, compared with the titers reached with constant substrate addition or pH-controlled batch cultures carried out under the same conditions. An interesting feature of fed-batch cultures observed under certain culture conditions (constant feed rate) is the apparent stabilization of bacteriocin activity after obtaining maximum production. Finally, a mathematical model was set up to simulate cell growth, glucose and complex nitrogen source consumption, and lactic acid and bacteriocin production kinetics. The model showed that bacterial growth was dependent on both the energy and the complex nitrogen source. Bacteriocin production was growth associated, with a simultaneous bacteriocin adsorption on the producer cells dependent on the lactic acid accumulated and hence the viability of the cells. Both bacteriocin production and adsorption were inhibited by high concentrations of the complex nitrogen source.

scholarly journals A buffered media system for yeast batch culture growth

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rianne C. Prins ◽  
Sonja Billerbeck
Keyword(s):  
Nitrogen Source ◽  
Ammonium Sulfate ◽  
Batch Culture ◽  
Biomass Production ◽  
Buffering Capacity ◽  
Drop Out ◽  
Batch Cultures ◽  
Media System ◽  
The Media ◽  
Media Types

Abstract Background Fungi are premier hosts for the high-yield secretion of proteins for biomedical and industrial applications. The stability and activity of these secreted proteins is often dependent on the culture pH. As yeast acidifies the commonly used synthetic complete drop-out (SD) media that contains ammonium sulfate, the pH of the media needs to be buffered in order to maintain a desired extracellular pH during biomass production. At the same time, many buffering agents affect growth at the concentrations needed to support a stable pH. Although the standard for biotechnological research and development is shaken batch cultures or microtiter plate cultures that cannot be easily automatically pH-adjusted during growth, there is no comparative study that evaluates the buffering capacity and growth effects of different media types across pH-values in order to develop a pH-stable batch culture system. Results We systematically test the buffering capacity and growth effects of a citrate-phosphate buffer (CPB) from acidic to neutral pH across different media types. These media types differ in their nitrogen source (ammonium sulfate, urea or both). We find that the widely used synthetic drop-out media that uses ammonium sulfate as nitrogen source can only be effectively buffered at buffer concentrations that also affect growth. At lower concentrations, yeast biomass production still acidifies the media. When replacing the ammonium sulfate with urea, the media alkalizes. We then develop a medium combining ammonium sulfate and urea which can be buffered at low CPB concentrations that do not affect growth. In addition, we show that a buffer based on Tris/HCl is not effective in maintaining any of our media types at neutral pH even at relatively high concentrations. Conclusion Here we show that the buffering of yeast batch cultures is not straight-forward and addition of a buffering agent to set a desired starting pH does not guarantee pH-maintenance during growth. In response, we present a buffered media system based on an ammonium sulfate/urea medium that enables relatively stable pH-maintenance across a wide pH-range without affecting growth. This buffering system is useful for protein-secretion-screenings, antifungal activity assays, as well as for other pH-dependent basic biology or biotechnology projects.

Using Alternating Tangential Flow with Fed-Batch Cultures

2019 ◽  
Vol 39 (10) ◽  
pp. 54-56
Author(s):  
Shashi Kudugunti ◽  
Daniel Diggins ◽  
Jyoti Amatya ◽  
Jamie Peyser
Keyword(s):  
Fed Batch ◽  
Batch Cultures ◽  
Tangential Flow

scholarly journals A novel process-based model of microbial growth: self-inhibition in Saccharomyces cerevisiae aerobic fed-batch cultures

2015 ◽  
Vol 14 (1) ◽  
Author(s):  
Stefano Mazzoleni ◽  
Carmine Landi ◽  
Fabrizio Cartenì ◽  
Elisabetta de Alteriis ◽  
Francesco Giannino ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Microbial Growth ◽  
Fed Batch ◽  
Batch Cultures

Ethanol production by anaerobic thermophilic bacteria: Kinetics in fed-batch cultures ofClostridium thermohydrosulfuricum

1989 ◽  
Vol 11 (6) ◽  
pp. 443-448 ◽  
Author(s):  
Fatiou Toukourou ◽  
Luiz Donaduzzi ◽  
Andr� Miclo ◽  
Pierre Germain
Keyword(s):  
Ethanol Production ◽  
Thermophilic Bacteria ◽  
Fed Batch ◽  
Batch Cultures
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