The contribution of chemical engineering to biotechnology

Professor Howard Chase FREng

Professor of Biochemical Engineering

Department of Chemical Engineering

Definitions

• Biotechnology - “the application of scientific and engineering principles to the processing of materials by biological agents to provide goods and services”

• Biochemical engineering - “the contribution of chemical engineering to biotechnology”.

BIOTECHNOLOGY

Microbiology

Botany

Zoology

Biochemistry

Chemical

engineering

Biochemical

Engineering

Protein

engineering

Genetics

Genetic

engineering

Medical

sciences

Where can biotechnology be applied?

• All applications benefit from an input of chemical engineering principles although the scales may not be the same as that encountered in the traditional oil and chemical industries. Some scales are smaller (e.g. healthcare) and some larger (environmental).

Biological cells: the source of sustainable molecules and more

• H2, CH4, O2, CO2

• Ethanol, butanol, acetone, propane-diol, biodiesel

• Organic acids, amino acids, flavourings

• Pharmaceuticals (e.g. antibiotics

• Biopolymers (plastics and rheology)

• Proteins: enzymes and therapeutics

• Gene therapy products (packaged nucleic acid sequences)

• Vaccines

• Microbial cells (environmental clean-up; waste treatment)

• Human cells (stem cells; tissue replacements)

• Hybrid products: bio/electrical/optical/mechanical (e.g. biosensors)

Why not chemical engineering? The chemical engineer’s tool-box

• Material and energy balances

• Thermodynamics and equilibria

• Separation principles and selectivity

• Heat and mass transfer

• Modelling

• Measurement techniques

• Processes

• Microstructure engineering

• Product design

Some outcomes for biotechnology

• Bioreactor design and optimization (fermenter mixing and aeration; biocatalysis)

• Separation and purification of (complex) biomolecules/molecular entities

• Controlled drug release; targeted drug delivery

• Scaffolds for tissue culture

• P &ID, Hazop/Hazan, Batch process scheduling; debottle-necking

• Systems’ biology

Biotechnology is not new to Chemical Engineering @ Cambridge

• Peter King: 1953 photosynthethic Chlorella with PVD

• John Davidson: 1980 member of committee for Spinks Report

• Deep shaft waste treatment processes & ICI’s Pruteen bioreactor

• Nigel Kenney: Packed bed processes for antibiotic purification.

• Nigel Slater: Maintenance of sterility in valves and pipes attached to fermenters

What has this department done recently? Healthcare

• Purification of molecules and biological assemblies produced in biological systems

• Targeted delivery of pharmaceuticals to cells.

• Purification of viruses and constructs for gene therapy.

• Separation of different types of human blood cells.

• Bioreactors for the growth of stem cells

• Separation of differentiated from non-differentiated stem cells.

Energy and the environment

• Biodiesel production from vegetable oils and algae

• Gasification of sewage sludge

• Oil production by pyrolysis of cellulosic materials.

• Reduced sludge production in activated sludge waste water treatment

• Biofilm reactors for degrading toxic compounds in aqueous wastes

Case study. Expanded bed adsorption for protein purification.

Packed BedPacked BedBlocks with particulatesBlocks with particulates

Fluidised BedFluidised BedWell mixedWell mixed

Poor adsorptionPoor adsorptionExpanded BedExpanded Bed

UUmf mf < U < U< U < Utt

~ 0.4~ 0.4 ~ 0.7-0.8~ 0.7-0.8

UU

• A quasi-packed bed through which particulates in non-clarified feeds can pass

Segregationof beads via distributions of size and density

Simplified Downstream Processing Flow Sheets

Conventional Process :Conventional Process :

50-80% total production costs50-80% total production costs

cascade of 5-6 stagescascade of 5-6 stages

decreasing yield with increasing number of stagesdecreasing yield with increasing number of stages

Expanded Bed Adsorption :Expanded Bed Adsorption :

clarification, concentration and purification in clarification, concentration and purification in one stageone stage

increase in yield through reduction in stagesincrease in yield through reduction in stages

The expanded bed in action: purification of enzymes from yeast cells

Expanding the bed

Applying the feedstock

Washing to remove particulates

Desorbing the desired enzyme

The future of biotechnology: a personal vision

• New therapeutics; gene therapy; personalized medicine; replacement organs

• Novel diagnosis

• Renewable feedstocks for the (petro)-chemical industries

• Direct biological energy production; photosynthesis

• Biological information storage: DNA versus silicon

• Improved environmental clean-up

The future of Chemical Engineering and Biotechnology

Chemical engineering has a pivotal role in the delivery of biotechnological discovery and innovation for the benefit of society

Biotechnology will continue to provide intriguing challenges for chemical engineers as the range, variety and extent of applications proliferates.

Chemical engineers have the appropriate ‘wherewithal’ to meet and surpass those expectations.

The right combination at the right time in the right place.