Maarg Manthan · Topic 10.6

Bioprocess and Fermentation Technology

Science & Technology › Biotechnology – Principles and Techniques · Topic 10.6

Bioprocess technology is the use of living cells or their enzymes to make useful products at an industrial scale, and fermentation is the central step in which microbes grow in a controlled vessel called a fermenter or bioreactor. The process has three stages: upstream work to choose the microbe and prepare the medium, the fermentation itself under controlled temperature, pH and oxygen, and downstream work to separate and purify the product. Products include antibiotics such as penicillin, enzymes, organic acids, alcohol, vaccines, biofuels and recombinant proteins such as insulin. Fermentation can be aerobic or anaerobic and can run as batch, fed-batch or continuous culture.

5 min read · UPSC Prelims · Science & Technology · Biotechnology – Principles and Techniques

At a Glance

Vessel Fermenter or bioreactor
Stages Upstream, fermentation, downstream
Modes Batch, fed-batch, continuous
Products Antibiotics, enzymes, acids
Conditions Temperature, pH, oxygen
Exam link UPSC Prelims, Science & Technology: Biotechnology – Principles and Techniques

Where Does It Fit?

This topic follows DNA sequencing and probes. It moves from reading genes to growing the microbes and cells that make products, which is the industrial side of biotechnology. Previous topic: DNA Sequencing and Nucleic Acid Probes. Next topic: Polymerase Chain Reaction (PCR).

What Are the Stages and Types of Bioprocess?

Item	Details
Upstream processing	Selecting and improving the microbe, preparing the growth medium and the inoculum, and sterilising the equipment
Fermentation	Growth and product formation in a controlled bioreactor with stirring, aeration, temperature and pH control
Downstream processing	Separating cells, extracting, purifying, concentrating and packing the product. It often costs more than the fermentation itself
Batch culture	Everything is put in at the start and the product is taken out at the end
Fed-batch culture	Nutrients are added during the run to avoid slow growth caused by too much substrate
Continuous culture	Fresh medium goes in and culture comes out at the same rate, giving a steady state
Solid state fermentation	Growth on moist solid material such as bran, used for enzymes and some foods

What Are the Parts of a Bioreactor and Its Products?

Stirred tank bioreactor: the most common type, with an impeller to mix and a sparger to supply sterile air
Control systems: probes and controllers keep temperature, pH, dissolved oxygen and foam within limits
Airlift and bubble column: mixing by gas bubbles, suited to delicate cells
Antibiotics: penicillin from the mould Penicillium, streptomycin from Streptomyces
Organic acids: citric acid from Aspergillus niger, lactic acid from Lactobacillus, acetic acid from Acetobacter
Enzymes: amylases, proteases and lipases for detergents, food and textiles
Alcohol and biofuel: ethanol from sugar by yeast, as in National Policy on Biofuels,…">Biofuels: Bioethanol, Biodiesel and Biogas from Biomass
Recombinant proteins: insulin and vaccines made in engineered bacteria, yeast or animal cells

What Else Should You Remember?

Aerobic and anaerobic: yeast makes alcohol without oxygen, while antibiotic moulds and citric acid production need air
Traditional fermentation: curd, idli, dosa batter, bread, wine and vinegar are made by natural fermentation
Louis Pasteur: showed that fermentation is caused by living microbes in the 1850s and 1860s
Alexander Fleming: discovered penicillin in 1928, and its large scale production started during the Second World War
Sterility: contamination by unwanted microbes can spoil a batch, so media, air and equipment are sterilised
Scale-up: a process that works in a flask must be tested in pilot tanks before industrial use
Immobilised cells and enzymes: fixed in beads or gels so that they can be reused, as in Bioprocessing, Bioreactors and Enzyme Manipulation in the Food Industry
Single-cell protein: microbial biomass as food or feed, as in Single-Cell Protein Production and Food Fortification
India: Indian firms and research bodies such as the Council of Scientific and Industrial Research and the Department of Biotechnology support bioprocess research and bio-manufacturing
Economics: downstream steps often make up a large part of the cost of a biological product
Biosafety levels: work with disease causing microbes needs containment, and production plants follow good manufacturing practice
Mixing and oxygen transfer: cells in a large tank need oxygen, and mixing becomes harder as the tank grows, so engineers study oxygen transfer rate
Foam control: protein rich broth foams, and antifoam chemicals are added to avoid loss
Biofilm and biocatalysis: enzymes or whole cells can serve as catalysts for chemical reactions, called biocatalysis, which is cleaner than many chemical routes
Vaccines: many vaccines are grown in cell culture or fermenters before purification
Product types: primary metabolites such as alcohol are made during active growth, while secondary metabolites such as antibiotics are made late in the growth phase

Why Does It Matter for the Exam?

Terms: upstream, downstream, inoculum, batch and continuous culture
Match questions: organism with product
Concepts: aerobic versus anaerobic
Current affairs link: bio-manufacturing, bioethanol and vaccine production
Common errors: confusing fermenter with fermentation, or thinking yeast needs oxygen for alcohol

As an analytical point, India has a large fermentation based industry, from vaccines to ethanol. Strengthening bio-manufacturing capacity and downstream expertise can reduce import dependence for enzymes and biological drugs.

Why Is This Topic Important?

Process Stages of bioprocess
Products Antibiotics and acids
Industry Bio-manufacturing

What Came Next?

The next topic covers the polymerase chain reaction. Next topic: Polymerase Chain Reaction (PCR).

Key People and Terms

Fermenter Vessel for microbial growth
Inoculum Starter culture
Downstream Purification stage
Sparger Air supply device
Batch One filling, one harvest
Impeller Stirrer

Exam Corner

Points to Remember

Penicillin: Fleming 1928, mould Penicillium.
Citric acid: Aspergillus niger.
Yeast alcohol: anaerobic.
Stages: upstream, fermentation, downstream.
Common tank: stirred tank.

Do Not Confuse With

Upstream and downstream Preparation versus purification
Batch and continuous culture Single harvest versus steady flow
Fermentation and respiration Industrial process or anaerobic pathway versus cell energy release

Memory Hook

Prepare the up, grow in the tank, purify the down; yeast without air, moulds with air.

Mains Angle

Questions ask about the stages and products. These points help.

Stages Up, middle, down
Products Health and energy
Challenge Scale and cost

A Question You May Face

An original practice question, not a past paper question.

“Describe the stages of a bioprocess and discuss how fermentation technology contributes to health care and industry.”

How to Answer

Meaning Microbes in a bioreactor.
Stages Upstream to downstream.
Products Drugs, enzymes, fuel.
Way Scale and skills.

GS Relevance

Prelims: fermentation types, bioreactor, products, upstream and downstream. GS Paper 3: science and technology, biotechnology, industry.

Frequently Asked Questions

What is fermentation technology?

Fermentation technology is the controlled use of microbes or cells in a bioreactor to make products such as antibiotics, enzymes, organic acids, alcohol and recombinant proteins. Conditions such as temperature, pH and oxygen are kept at the best level, and the product is then separated and purified.

What is the difference between upstream and downstream processing?

Upstream processing covers all steps before fermentation, such as selecting the microbe, preparing the medium and sterilising equipment. Downstream processing covers steps after fermentation, such as separating cells and purifying the product. Downstream work often forms the largest part of production cost.

What is a bioreactor?

A bioreactor is a closed vessel in which microbes or cells grow under controlled conditions to make a product. The stirred tank type is most common, with a stirrer for mixing and a sparger for air, and with sensors that control temperature, pH and dissolved oxygen.

What are batch and continuous cultures?

In batch culture all nutrients are added at the beginning and the product is harvested at the end of the run. In continuous culture, fresh medium is fed in and culture is removed at the same rate, so growth continues in a steady state for a long period.

Which microbes make penicillin and citric acid?

Penicillin is made by the mould Penicillium, which Alexander Fleming noticed in 1928 to kill bacteria. Citric acid is made industrially by the mould Aspergillus niger fermenting sugar. Both are examples of industrial fermentation using fungi grown under controlled aerobic conditions.

PYQ Practice — Statement Analysis

1 Downstream processing includes purification of the product.

True

After fermentation.

2 Citric acid is produced industrially by Aspergillus niger.

True

A mould.

3 Alcoholic fermentation by yeast needs plenty of oxygen.

False

It is anaerobic.

4 In continuous culture, nothing is added after the start.