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Design of STR Bioreactor for Production of Saccharomyces cerevisiae (Upstream processing)
Poster · April 2014
DOI: 10.13140/RG.2.2.14560.58881
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3 authors, including:
Nasser Madkhali
Saleh Matar
King Abdulaziz City for Science and Technology
Jazan University
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Design of STR Bioreactor for Production of
Saccharomyces cerevisiae (Upstream processing)
Nasser Madkhaly, Othman Mohammed-Abdu, Advisor: Dr. Saleh Matar
Department of Chemical Engineering, University of Jazan, Kingdom of Saudi Arabia (KSA)
.
Abstract
The purpose of this work was to design a bioreactor to simulate the standard design
factors of the bench-top scale. An air sparger was designed for pumping 2 vvm sterile
air and a mechanical stirrer was used for agitation while a two blade type rushton
impeller is designed for agitation. The designed model was operated by running the
Saccharomyces cerevisiae (baker`s yeast) in batch mode cultivation. The optimization
of growth was identified in a shake flasks to establish the optimized condition of
temperature, pH and agitation. The results showed that the optimum temperature, pH
and agitation were 34°C, 5.3 and 500 rpm respectively. The cultivation process in the
designed prototype was conducted under the obtained optimized parameters. The
growth curve reached to the maximum biomass production of 35.9 g/l i.e. 100% more
than those produced in shake flask (17.99g/l).
Operational procedure
The experimental procedures were conducted in two main steps: determination the
optimum condition in Shake flasks for temperature, pH and agitation and
confirmation the results in the designed bioreactor.
The derivatives for biomass generation with respect to time, is related to specific
growth rate which is defined as follows:
The following equation was used to predict the cell growth in batch experiments.
Introduction
Bioreactors in some form or another have been around for thousands of years, although
up until the 1900s their use was limited to the production of potable alcohol. It was
really from the 1940s onwards that fermentation as it is known today began to appear
with the need to produce antibiotics during World War Two. Deep understanding of bioprocessing may require actual knowledge of biology and microbiology in the
applications of Biochemical processes. It is very interesting to demonstrate bench-scale
experiments and make use of large-scale advanced technology. However, application of
the bioprocess in large-scale control of microorganisms in 100,000 liters of media may
not be quite so simple to manage.
The main objective of this project was to design a bench-top bioreactor, taking into
account the standard design criteria. Designed prototype model was directed to
evaluate the optimum condition for the ability of growing microorganism in batch culture
as an up-stream processing. This work focused mainly on studying the optimum
operational condition such as temperature, agitation and pH, as well as the kinetics and
growth behavior of Saccharomyces cerevisiae (baker`s yeast) during cultivation.
Problem Definition and Design
Key goals of the project were determined from the problem of maximizing the biomass
production and expanded into a complete list of objectives and constraints. The list was
split into objectives for the bioreactor design and objectives for the bio-production of
Saccharomyces cerevisiae in batch process optimization study an comparison charts
were used to weigh the importance of each objective and constraint.
Instillation of designed bioreactor with associated utilities.
Cultivation in Shake Flask
The experimental procedures were conducted in two main steps: determination the
optimum condition in Shake flasks for temperature, pH and agitation and
confirmation the results in the designed bioreactor.
Optimization of Agitation
Optimization of pH
Optimization of temperature
Cultivation in Bioreactor
Bioreactor constituents and connected parts on head plate Growth of S. cerevisiae was determined with respect to the determined optimized
condition of temperature, pH and agitation. The controlling of fermentation process
was conducted in the model designed bioreactor as the preparation of bioreactor
operation procedures started with inoculation the bioreactor with the 200 ml broth
shake flask incubated in 34 ºC and pH = 5.3. the inoculated amount was maintained
at 15% of pre-culture.
The objectives were broken further into sub-objectives and both were compiled to
accomplish the controlled fermentation process. After an in-depth discussion on what
features, attributes and functions the bioreactor should satisfy, objectives and
constraints for the bioreactor were determined. In order to fulfill the goal function, the
bioreactor was designed to produce a biomass or metabolic bio-product in a glass
reactor and the yeast cell population reproduces according to the kinetic model
behavior.
Variation of biomass with time
lnX vs time in the xponential
growth phase
Future Work
This work was conducted in batch mode cultivation and this is the simplest and the
easiest bioprocess in bioreactor for any microorganism. It may be recommended to
check the cultivation in the other modes of fermentation like as continuous and fed
batch fermentation. In addition to this the larger scale can be designed. This will help
in driving the cultivation of microorganism to operate in scale-up processes. On the
other side this prototype can use to investigate the other microorganisms such as
bacteria and algae and use different processing behavior without or in the presence
aeration.
References
Bioreactor working volume, Vworking = volume of broth with 20% - 30% over-design as
a safety factor. In the designed bioreactor, the desired working volume of 1300 ml
was selected for cultivation experiments. Accordingly, the head space for the
selected reactor vessel become 28.5 % in relation to the total volume which
calculated as follow: Vworking = 1300ml / 0.71.5 ≈ 1818 ml.
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1. Anke, S., Schneppe, B., McCarthy, J. E. G., Deckwer, W.-D. and Rinas, U. (1995),
Comparison of temperature and isopropyl-β-D-thiogalactopyranoside-induced
synthesis of basic fibroblast growth factor in high cell density cultures of
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4. Saleh M. Matar (2001): Bioprocessing of genetically modified Escherichia coli in
stirred tank bioreactor for valuable protein production. Ph.D. Thesis, Minia
University.
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