Chapter 1: Introduction to

Bioreactors

Those that aim to produce cell mass (biomass)

Those where the product is produced by the cells, eg enzyme or metabolite

Those that modify a compound which is added to the fermentation (biotransformation)

Types of Fermentation

Started with the production of Baker’s yeast for baking industries.

Microbial biomass for protein source. Bacteria, yeast and fungi (eg spirulina) Single cell protein (SCP)

Biomass Production

Single cell protein

Beer, wine, food additives, cheese Ethanol, acetone, butanol, enzymes Antibiotics, monoclonal antibodies, vaccines SCP Waste treatment

Products produced by cells

Production of steroids Conversion of antibiotics

Biotransformation

Culture types

Culture types Special Characteristics

Bacteria

Yeast

Fungi

Algae

Animal & plant cells

May be highy aerobic or thermophilic

May be highly aerobic

Can be mycelial, highly viscous cultures

Often require light for growth

Slow growing, delicate

Upstream & DownstreamUPSTREAM

Medium preparationInoculum

Bioreactor

DOWNSTREAM

Separation

Biomass Product purification

Operated by supplying an essential growth-limiting nutrient at a constant rate with the result that the culture density and growth rate adjust themselves to the supply.

Chemostat

Operated by maintaining a constant cell density by supplying fresh medium as required.

It possesses a photocell system which continuously monitors the cell density and maintains this constant by controlling the medium inlet flowrate.

Turbidostat