Modeling the dynamics of E. coli populations in the three-dimensional turbulent field of a stirred-tank bioreactor—A structured–segregated approach

2006 ◽  
Vol 61 (14) ◽  
pp. 4783-4797 ◽  
Author(s):  
Alexei Lapin ◽  
Joachim Schmid ◽  
Matthias Reuss
2015 ◽  
Vol 40 (4) ◽  
Author(s):  
Arbakariya Bin Ariff ◽  
Rubina Nelofer ◽  
Raja Nor Zaliha Raja Abdul Rahman ◽  
Mahiran Basri

AbstractObjective: Kinetics of organic solvent tolerant and thermostable lipase production by recombinant E. coli in shake flask level and 2 L stirred tank bioreactor level was studied to observe the variations of important kinetic parameters at two different levels of bioprocess.Methods: Unstructured models based on Monod equation for growth and Luedeking-Piret equation for lipase production and glucose consumption were used to predict cell growth, lipase production and glucose utilization. The shake flask fermentation experiments were carried out at different initial glucose and yeast extract concentrations using recombinant bacterial strain E. coli BL21. Lipase production was also carried out using 2L stirred tank bioreactor for comparison.Results: In all cases, the data fitted well to the proposed models. The highest growth and lipase activity were obtained at 25 g/L glucose and 25 g/L yeast extract. Cell growth (6.42 g/L) and lipase production (65.32 IU/mL) in 2 L stirred tank bioreactor was comparable to those obtained in shake flask fermentations. The calculated value of growth associated constant (9.874 IU/g/h) was much higher than that of non-growth associated constant (0.022 IU/g/h) in bioreactor as well as in shake flasks. The values of maximum specific growth rate (μm) and glucose saturation constant (KS) for shake flask fermentations, calculated from Monod equation, were 0.476 h-1 and 5.237 g/L respectively.Conclusion: From the modelling exercise, it was concluded that the lipase production is dominantly growth associated process. The kinetic parameter values for fermentations in shake flask and 2L stirred tank bioreactor were comparable, indicating that the bioprocess could be transferred into larger scale.


2011 ◽  
Vol 28 (1) ◽  
pp. 66-75 ◽  
Author(s):  
Shaukat Ali ◽  
Miguel Angel Perez-Pardo ◽  
Jean P. Aucamp ◽  
Alan Craig ◽  
Daniel G. Bracewell ◽  
...  

2018 ◽  
Author(s):  
George Catalin Marinescu ◽  
Roua Gabriela Popescu

Growing microorganisms for laboratory experiments or industrial biotechnological process is an activity which involves the use of bioreactors. Although there are many commercially available equipment, most of them lack the flexibility of an open-source solution. This work proposes a cost effective Arduino based bioreactor controller for growing suspended microbial cells. To exemplify its functionality, this study provides the parts list and schematics necessary to make a functional laboratory scale bench top stirred tank bioreactor. Using the built prototype, an E. coli culture is grown maintaining the preset parameters, protein expression is induced and culture is harvested at preset culture density. Automatically recorded process data shows stable environmental parameters and reliable bacterial growing curve.


2018 ◽  
Author(s):  
George Catalin Marinescu ◽  
Roua Gabriela Popescu

Growing microorganisms for laboratory experiments or industrial biotechnological process is an activity which involves the use of bioreactors. Although there are many commercially available equipment, most of them lack the flexibility of an open-source solution. This work proposes a cost effective Arduino based bioreactor controller for growing suspended microbial cells. To exemplify its functionality, this study provides the parts list and schematics necessary to make a functional laboratory scale bench top stirred tank bioreactor. Using the built prototype, an E. coli culture is grown maintaining the preset parameters, protein expression is induced and culture is harvested at preset culture density. Automatically recorded process data shows stable environmental parameters and reliable bacterial growing curve.


Author(s):  
James A. Lake

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.


Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.


Author(s):  
Daniel Beniac ◽  
George Harauz

The structures of E. coli ribosomes have been extensively probed by electron microscopy of negatively stained and frozen hydrated preparations. Coupled with quantitative image analysis and three dimensional reconstruction, such approaches are worthwhile in defining size, shape, and quaternary organisation. The important question of how the nucleic acid and protein components are arranged with respect to each other remains difficult to answer, however. A microscopical technique that has been proposed to answer this query is electron spectroscopic imaging (ESI), in which scattered electrons with energy losses characteristic of inner shell ionisations are used to form specific elemental maps. Here, we report the use of image sorting and averaging techniques to determine the extent to which a phosphorus map of isolated ribosomal subunits can define the ribosomal RNA (rRNA) distribution within them.


Author(s):  
Douglas L. Dorset ◽  
Andrew K. Massalski

Matrix porin, the ompF gene product of E. coli, has been the object of a electron crystallographic study of its pore geometry in an attempt to understand its function as a membrane molecular sieve. Three polymorphic forms have been found for two-dimensional crystals reconstituted in phospholipid, two hexagonal forms with different lipid content and an orthorhombic form coexisting with and similar to the hexagonal form found after lipid loss. In projection these have been shown to retain the same three-fold pore triplet geometry and analyses of three-dimensional data reveal that the small hexagonal and orthorhombic polymorphs have similar structure as well as unit cell spacings.


Author(s):  
J.L. Carrascosa ◽  
G. Abella ◽  
S. Marco ◽  
M. Muyal ◽  
J.M. Carazo

Chaperonins are a class of proteins characterized by their role as morphogenetic factors. They trantsiently interact with the structural components of certain biological aggregates (viruses, enzymes etc), promoting their correct folding, assembly and, eventually transport. The groEL factor from E. coli is a conspicuous member of the chaperonins, as it promotes the assembly and morphogenesis of bacterial oligomers and/viral structures.We have studied groEL-like factors from two different bacteria:E. coli and B.subtilis. These factors share common morphological features , showing two different views: one is 6-fold, while the other shows 7 morphological units. There is also a correlation between the presence of a dominant 6-fold view and the fact of both bacteria been grown at low temperature (32°C), while the 7-fold is the main view at higher temperatures (42°C). As the two-dimensional projections of groEL were difficult to interprete, we studied their three-dimensional reconstruction by the random conical tilt series method from negatively stained particles.


1985 ◽  
Vol 40 (11) ◽  
pp. 1114-1120
Author(s):  
loan Motoc ◽  
Garland R. Marshall

A methodology to incorporate the three-dimensional molecular shape descriptor (3 D-MSD) into a quantitative structure-activity relationship is discussed in detail. The 3 D-MSD is calculated and correlated with Kiapp values for a set of 2,4-diamino-5-benzylpyrimidines which inhibit E. coli DHFR. The correlation (n = 22, r = 0.95, s = 0.214, F = 55.10) indicates that the polarization interaction dominates the enzyme-inhibitor interactional pattern.


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