04221 - Industrial Microbiology

Academic Year 2021/2022

  • Teaching Mode: Traditional lectures
  • Campus: Bologna
  • Corso: Second cycle degree programme (LM) in Molecular and industrial biotechnology (cod. 9213)

Learning outcomes

At the end of the course the student acquires theoretical and practical knowledge of the industrial fermentation processes through the study of the phases of which they are composed.

In particular, the student acquires knowledge about:

i) the different strategies aimed at the optimization of the final productivity of the process,

ii) the bacterial growth kinetics and the mathematical modeling of fermentation processes,

iii) the main types of bioreactors used in the biotechnology industry,

iv) the down-stream process of isolation of the product of interest starting from the fermentative broth up to the commercial form, and its influence on the economy of the production process,

v) the main groups of microorganisms of industrial interest,

vi) the study of several examples of industrial processes for the fermentative production of primary, secondary, heterologous proteins and bioethanol.

At the end of the course the student is therefore able to understand how to manage and optimize an industrial fermentation process.

Course contents

A historical introduction of the Industrial Fermentations.

Unitary Operations of an Industrial Fermentation.

Types of industrial fermentation processes.

Batch fermentation.

Fed-batch fermentation.

Continuous fermentation.

Continuous fermentation with recycling.

Kinetics of bacterial growth.

Growth phases in a batch fermentation.

Specific growth rate and generation time.

Methods for measuring cell concentration.

Cell number measurement.

Cell mass measurement.

Direct methods.

Indirect methods.

Bioconversion yields of the substrate in biomass and product.

Kinetics of combustion of the growth limiting substrate.

Model of Monod.

Growth in complex media.

Microbial growth related to the environment.

Effect of temperature.

Effect of pH.

Effect of high concentrations of nutritites.

Effect of insoluble nutritites.

Kinetics of product formation.

Product formation linked to growth.

Formation of products partially linked to growth.

Product formation not linked to growth.

Primary and secondary metabolites.

Fed-batch fermentations.

Kinetics and industrial applications of fed-batch fermentations.

Continuous fermentations.

Kinetics of continuous cultures.

Mass balances in continuous fermentations.

Types of continuous fermentations.

Chemostat and turbidostat.

Advantages and industrial applications.

Continuous fermentations with recycling.

Kinetics of continuous cultures with recycling.

Mass balances in continuous fermentation with recycling.

Types of continuous crops with recycling.

Biomass recycling and medium recycling.

"Plug" type bioreactors.

Main types of birreators.

Stirred Tank reactors.

Air lift reactors.


Unitary Fermentation Operations during and at the end of the fermentation process.

Aeration and agitation.

Parameter control.


Final harvest.

General information on the main down stream processes.

Removal of solids.

Primary isolation.


Final product processing.

Main microbial groups of industrial interest.


Spore-forming bacteria.

Proponibacteria and Corinebacteria.





Eumycetes: yeasts and fungi.

Industrial processes of production of primary and secondary metabolites.


  Organic acids.




Note: during the course, and depending on the progress of the program, chats will be held on current issues related to the biotechnology field, as proposed by the students.


Fermentation. A practical approach. B. McNeil and L.M. Harvey. Irl Press (1990)

Modeling and Optimization of Fermentation Processes. B. Volesky and J. Votruba. Elsevier (1992)

Microbiology Concepts and Applications. Michael J Pelczar Jr, ECS Chan and Noel Krieg. McGraw Hill (1993)

Bioreaction Engineering Principles. J. Nielsen, John Villadsen, G. Lidén. Kluwer Academic/Plenum Publishers (2002)

Teaching methods

Academic lectures.

Assessment methods

Written test.

Teaching tools

Course notes.

Office hours

See the website of Antonio Gonzalez Vara Rodriguez


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This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.