Advanced Bioprocess Engineering INTRODUCTION Lecturer Dr. Kamal E. M. Elkahlout

Advanced Bioprocess Engineering
INTRODUCTION
Lecturer Dr. Kamal E. M. Elkahlout
Assistant Prof. of Biotechnology
Relationship of Scientists
Engineers
• Microbiologists, biochemists, and
molecular biologists are scientists,
well-trained in empirical testing of
hypotheses.
• Engineers develop theories based on
mathematical models, use models to
predict performance, optimize and
develop processes.
Biologists and Engineers
• Research scientists often pursue
knowledge while applications
may take a secondary role.
• The work of engineers is often
driven by economics of an
application and problem
solving.
• A bioprocess is any process that uses complete
living cells or their components (e.g., bacteria,
enzymes, chloroplasts) to obtain desired products
• Transport of energy and mass is fundamental to
many biological and environmental processes.
• Areas, from food processing to thermal design of
building to biomedical devices to pollution control
and global warming, require knowledge of how
energy and mass can be transported through
materials[mass,momentum,heat transfer]
Bioprocess Engineering
• It is a specialization of Biotechnology, Chemical
Engineering or of Agricultural Engineering.
• It deals with the design and development of
equipment and processes for the manufacturing of
products such as food, feed, pharmaceuticals,
nutraceuticals, chemicals, and polymers and paper
from biological materials.
• Bioprocees engineering is a conglomerate of
mathematics, biology and industrial design,
• It consists of various spectrums like designing of
Fermentors, study of fermentors (mode of operations
etc).
• It also deals with studying various biotechnological
processes used in industries for large scale
production of biological product for optimization of
yield in the end product and the quality of end
product.
• Bio process engineering may include the work of
mechanical, electrical, and industrial engineers to
apply principles of their disciplines to processes
based on using living cells or sub component of such
cells.
Definition of Fermentation
• Metabolism: energy generating processes
where organic compound acts as both electron
donor and acceptor.
• Industrial Biotechnology: the process by which
large quantities of cells are grown under
aerobic or anaerobic conditions.
• The industrial microorganisms are grown
under controlled conditions with an aim of
optimizing the growth of the organism for
production of a target microbial product.
Definition of Fermentation
• Fermentation is carried out in vessels
known as Fermentors
• The types of fermentor ranges from simple
tank to complex integrated system of
automated control.
An overview of a typical industrial fermentation process and the
movement of materials through a typical fermentation plant are
shown in the following figure:
Fermentation Plant
The Process of Fermentation
• Process is divided into a number of sections:
• · In-bound logistics: (the delivery and storage of raw materials)
• · Upstream processing: the processing of raw materials for the
fermentation
• · The fermentation, where the major conversion occurs
• · Downstream processing: the purification and concentrating of
the raw product(s)
• · Out-bound logistics : the final packaging, storage and delivery
of the purified product(s)
• Stages of Industrial fermentation:
• · Upstream Processing (USP)
• · Downstream Processing (DSP)
Upstream Processing
• The upstream part of a bioprocess refers to the first
step in which microbes/cells are grown, eg bacterial
or mammalian cell lines (see Cell culture), in
bioreactors.
• Basically upstream processing involve all those
steps related with inoculum development, media
development, improvement of inoculum by genetic
engineering process, optimization of growth kinetics
so that product development can improve
tremendously.
• Fermentation has two part upstream & downstream.
• After product development the next step is
purification of product for desired quality.
• When they reach the desired density (for batch and
fed batch cultures) they are harvested and moved to
the downstream section of the bioproces
Upstream Processing
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Three main areas:
A) Producer microorganism
This include processes for
obtaining a suitable microorganism
strain improvement to increase the productivity and
yield
maintenance of strain purity
preparation of suitable inocullum
B ) Fermentation media
C) Fermentation Process
Downstream Processing
• The downstream part of a bioprocess refers to the
part where the cell mass from the upstream are
processed to meet purity and quality requirements.
• Downstream processing is usually divided into three
main sections,
• a capture section,
• a purification section and
• a polishing section.
• The volatile products can be separated by distillation
of the harvested culture without pre-treatment.
• Distillation is done at reduced pressure at continuous
stills.
• At reduced pressure distillation of product directly
from fermentor may be possible.
• The steps of downstream processing are:
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1-separation of biomass
2-cell disruption
3-concentration of broth
4-initial purification of metabolites
5-metabolite specific purification
6-de-watering
7-polishing of metabolites
• 1-separation of biomass: separating the biomass
(microbial cells) generally carried out by
centrifugation or ultra-centrifugation. If the product
is biomass, then it is recovered for processing and
spent medium is discarded. If the product is extra
cellular the biomass will be discarded.Ultra filtration
is an alternative to the centrifugation.
2-cell disruption: If the desired product is intra
cellular the cell biomass can be disrupted so that the
product should be released. The solid-liquid is
separated by centrifugation or filtration and cell
debris are discarded.
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• 3-concentration of broth: The spent medium is
concentrated if the product is extracellular.
• 4-initial purification of metabolites: According to
the physico-chemical nature of the product molecule
several methods for recovery of product from the
clarified fermented broth were used ( precipitation,
solvent extraction, ultra-centrifugation, ionexchange chromatography, adsorption and solvent
extraction)
• 5-metabolite specific purification: specific
purification methods are used when the desired
metabolite is purified to a very high degree.
• 6-de-watering: If low amount of product is found in
very large volume of spent medium, the volume is
reduced by removing water to concentrate the
product. It is done by vacuum drying or reverse
osmosis.
• 7-polishing of metabolites: this is the final step of
making the product to 98 to 100% pure.the purified
product is mixed with several inert ingredients
called EXCIPIENTS. the formulated product is
packed and sent to the market for the consumers.
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Types of Fermentation Process
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Batch Fermentation
Continuous Fermentation
Fed batch
Batch reactors ,simplest type. Reactor is filled with
medium and the fermentation is allowed.
• Fermentation has finished, contents are emptied for
downstream processing.
• The reactor is then cleaned, re-filled, re-inoculated
and the fermentation process starts again.
Types of Fermentation Process
• Continuous reactors, where fresh media is
continuously added and bioreactor fluid is
continuously removed.
• As a result, cells continuously receive fresh medium
and products and waste products and cells are
continuously removed for processing.
• The reactor can thus be operated for long periods of
time without having to be shut down.
• Many times more productive than batch reactors.
Types of Fermentation Process
• does not have to be shut down as regularly
• the growth rate of the bacteria in the reactor
can be more easily controlled and optimized
• cells can also be immobilized in continuous
reactors, to prevent their removal.
• Fed batch reactor, most common type of
reactor used in industry.
• fresh media is continuous or sometimes
periodically added.
Batch Fermentation Process
• dynamic processes that are never in a steady
state.
• Often , the critical parameter is gas
exchange or balance between respiration
rate and oxygen transfer.
• sterilized media components are supplied at
the beginning of the fermentation with no
additional feed after inoculation.
Batch Fermentation Process
• cells are grown in a batch reactor, they go
through a series of stages:
• Lag phase
• · Exponential phase
• · Stationary phase
• · Death phase
Batch Fermentation Process
Batch Fermentation Process
• Lag Phase
• microbial population remains constant as there is no growth.
However it is the period of intense metabolic activity.
• Factors Influencing the Lag Phase
• · Chemical composition of the fermentation media influences the
length of the lag phase.
• Longer lag phase is observed if the inocullum is transferred into a
fresh medium of different carbon source.
• · Age of the inocullum. If the inocullum is in exponential growth
phase, it will exhibit shorter lag in the fresh medium.
• · Concentration of the inocullum.
• · Viability and morphology of the inocullum.
Penicillin: “Birth of
Biochemical Engineering”
• 1928- Alexander Flemming was plating
Staphylococcus aureus and the plate was
contaminated with mold – near the mold no
bacteria grew.
• WWII- most common cause of death was
infection from wounds.
• Sulfa drugs were effective on limited range of
infectious organisms.
• 1930-1940 British scientists Florey and Chain at
Oxford developed a process to produce penicillin
from the mold.
How Penicillin Works...
Antibiotics on a plate: cell walls do not form
Early Work
• They asked US pharmaceutical
companies to help work on the project –
to develop a commercial scale process
for penicillium.
• Merck, Pfizer, Squibb, USDA
• At this time, most drugs were made
synthetically. Fermentation was
unproved and companies were skeptical.
• Problem: low concentrations, fragile
product.
Significant Advances
• New medium- Corn steep liquor
(x10).
• New strain isolated from molded
fruit- P. chrysogenum (still used in
some form).
• Change to tanks from “bottle plants”.
• Separation: liquid-liquid extraction.
Challenges
• Very large (10 kgal) fermentation
vessels.
• Provide sterile air and feed.
• Agitator seal.
• Heat removal.
• Recovery and purification of fragile
product.
Biology-Engineering Connection
• Cooperation between engineers and
scientists was critical (Merck
specifically formed teams of each).
• “Biochemical engineering” born as a
result.
• • Essential Knowledge/ Topics needed in Bioprocess
engineering work
• – Cells
• – How cells work
• – Metabolism Pathways
• – Enzymes and Kinetics
• – Reactors: Design and Data Analysis
• – Bioseparations
• – Application and Industrial considerations
Oxygen transfer rate
Oxygen utilization rate
Cleaning in place/sterilization in place