Bioprocess Principles

BIOPROCESSPRINCIPLES

Unit Operations inUpstream & Downstream

Processing

April 21, 2023 Unit Operation in a Bioprocess(Upstream & Downstream)

DefinitionDefinition

These “fundamental” operations are what are called “unit operations”.

Chemical and Bioprocess Industries consist of widely varying sequences of steps that have different combinations for different manufacturing cycles.

What is a Unit operation?

However these widely varying steps can be reduced or broken down to simple operations which are identical in fundamentals regardless of the material being processed.


Historical DefinitionHistorical Definition

This definition was used by A.D Little in 1915 to describe Unit Operations.

““Unit operations deal mainly with the Unit operations deal mainly with the transfer of energy and the transfer and transfer of energy and the transfer and change of materials primarily by change of materials primarily by physical means”.physical means”.

What is a Unit Process?What is a Unit Process?


Different Unit OperationsDifferent Unit Operations

Drying Distillation Adsorption Membrane

separation Leaching Sedimentation Mixing Liquid Liquid

Extraction Absorption

TRANSPORT PHENOMENA

Momentum Transfer Fluid Flow Sedimenation Mixing

Heat Transfer Drying Evaporaytion (SHMT) Distillation

Mass Tranfer Absorption Adsorptin Distillation


Stages of a BioprocessStages of a Bioprocess

A biotechnical process to produce a product can be subdivided into five successive major segments, with some overlap:

• upstream processing• fermentation• downstream processing • product finishing• treatment of waste if any


Stages of a Traditional Stages of a Traditional BioprocessBioprocess


Stages of a Bioprocess Stages of a Bioprocess (Details)(Details)

Preparation of sterile medium. Addition (inoculation) of microbe ( pure culture)

into this medium Cultivation (incubation) under controlled

conditions Sterilising fermentation apparatus and preparing

and sterilising feed streams to the fermentorFERMENTATION

Isolation and purification of the product from the fermented medium

Packaging of the product Treatment of the waste products if any


Unit Operations in a Unit Operations in a BioprocessBioprocess


Upstream ProcessingUpstream Processing

“Pure Upstream processing” has essentially three functions:

Growth of a pure culture of microorganisms in one or more steps its scale up and strain development.

Sterilization of the apparatus and piping. Mixing and sterilizing the necessary raw

materials and fermentation media to be supplied to the fermentation unit.


Fermentation StageFermentation Stage

Sometimes considered as an Upstream process while some bioprocess engineers consider it as a

separate Stage in itself. Never considered as a downstream processing stage

Actual fermentation is commonly a batch or fed batch process in a stirred tank fermentor.

It lasts from a few hours to several days. The optimal conditions for growth of the organisms

and production of the product are established. Those include temperature, pH, sterile aeration and, in fed-batch processes, continuous addition of substrate at its optimal composition.


SCALE UP (DEFINITION)SCALE UP (DEFINITION)

Shake flash Experiments Lab scale fermentor (5-10 L) Pilot scale fermentor (300-3000 L) Commercial fermentor (10,000-500,000

L)

•Scale up: The transfer of a process from small-scale laboratory equipment to large-scale commercial equipment


lab flask (100 mL)

lab-scalefermentor(1–10 L)

pilot plantscale

(300-3000 L)commercial scale(10,000-500,000 L)

Scale upScale up


Industrial Scale upIndustrial Scale up


Industrial Fermentation SettingIndustrial Fermentation Setting


Fermentor sizes for various purposesFermentor sizes for various purposes


Some problems in Scale upSome problems in Scale up

Oxygen transfer is much more difficult to obtain in large-scale

Mixing and aeration more easily accomplished in small volumes

Methods of temperature control must change with scale-up

Sterilization protocols must change with scale-up

Bioprocess Engineers required with Chemical Engineering skills: adept in gas and mass transfer, fluid dynamics, mixing, thermodynamics


Downstream processingDownstream processing

Downstream processing (DSP) encompasses all processes following the fermentation.

In “downstream processing”, the fermentor is emptied after the fermentation is complete. The microorganisms are killed and, if necessary, removed by ultrafiltration. The liquor may be concentrated by evaporation. If necessary, the active ingredient may be isolated by a suitable separation process such as crystallization, ion-exchanging or chromatography. The subsequent product finishing is intended to transform the product into the desired marketable form, e. g., into a dry pourable granulation. That is accomplished by classical drying and granulation processes.


Unit Operations in Unit Operations in Down Stream Processing Down Stream Processing

Pre- treatment

Solid /liquidSeparation

Concentration

Purification

Formulation

Cell disruptionStabilizationSterilizationPasteurization Flocculation

FiltrationSedimentaionCentrifugation

MembranesPrecipitation

EvaporationExtraction

Freeze Concentration

PrecipitationExtractionDiafilterationAdsorption

Chromatography

DryingPrillingExtrusionGranulationTabletting


Relationship Relationship (between cost and (between cost and and fermentation concentration)and fermentation concentration)


Separation Range of Separation Range of Downstream Unit OperationsDownstream Unit Operations


Product Quality ProfileProduct Quality Profile (during Downstream Processing Stages)(during Downstream Processing Stages)

DifferencesDifferences

Upstream Processing

Downstream processing

Live Organisms No organisms

Large Volume Progressively Less Volume

Many Components Progressively less components

Heterogeneous mixture

Homogenous Mixture

Fewer Operations Many Operations

Lower Cost materials Higher Cost materials



Downstream ProcessingDownstream Processing

Downstream Processing begins upstream…why?

A “holistic” approach to DSP is required and the entire process as a whole should be considered. The economic use of cheap industrial fermentation sources could cause interactions that could increase downstream processing difficulty and cost.. Hence a balance should be sought in the whole process which should be done by the Bioprocess Engineer.


Research Areas in Upstream Research Areas in Upstream processingprocessing Research areas in upstream processing being carried out

today Testing, modeling, optimization, control of novel or

improved recombinant and non-recombinant cell cultures

New biochemical reactors, and new biological processes to produce useful and high value products.

Basic genome and proteome based biomolecular engineering studies that lead to improved design and performance of fermentation and cell culture processes.

By using on-line and real time sensing and monitoring techniques and high throughput analytical techniques

Quantitative assessment of biomolecular rate processes inside a cell toward increasing aeration and transfer rates


Research Areas in Research Areas in Downstream processingDownstream processing The capability to purify bioproducts in a cost-

effective manner on a commercial scale and to meet the required high purity specification for the medical grade bioproducts is an important technical goal of R & D.

Research in areas as posttranslational protein processing, protein refolding, protein purification techniques, membrane technology,

Various types of chromatography including bioaffinity systems, separation techniques using combined force fields, and filtration methods.

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Bioprocess Principles