21365 - General Microbiology

Learning outcomes

At the end of the course, the student knows the general characteristics of microbial cells and acquires the skills and terminology necessary to understand the mechanisms of microbial growth. Furthermore, the student is able to tackle subsequent courses related to wine microbiology.

Course contents

General concepts. Scope of general microbiology, definitions, and the importance of the microbial heritage, as well as the relevance of the subject as a foundation for wine microbiology.

Bacterial classification. Phylogeny. Methods of classification: genotype and phenotype. Definition of the main genera and species of interest in enological microbiology. Classification of Bacteria. Main phyla (Proteobacteria, Firmicutes, Actinobacteria). Characteristics and placement of the main bacterial microbial groups.

Fungal classification. yeasts and molds. Sexual and asexual reproduction; ascomycetes and basidiomycetes.

Cell structure. Composition and general functions of the microbial cell. Morphology and structure of microbial cells. Eukaryotic and prokaryotic cells: differences and shared features. Spore formation.

Cell growth. Culture media: definition, classification, preparation. Microorganism counts. Microbial growth curve: lag phase, exponential phase, stationary phase, and death phase. Diauxic growth, chemostats. Concept of homeostasis. Main intrinsic and extrinsic factors influencing microbial growth.

Nutrition and cellular transport systems. Chemical components. Energy (phototrophy, chemotrophy, lithotrophy). Organic matter (autotrophs, heterotrophs). Growth factors. Transport systems (primary, secondary, group translocation).

Microbial metabolism. Energy processes. Fermentation and respiration. Electron transport, redox potential, and bioenergetics. Membrane carriers (NADH, quinones, cytochromes, Fe–S proteins, flavoproteins). Proton motive force, ATP, CoA. PMF generation: stages. ATPase.

Energy cycles. Glycolysis. Entner–Doudoroff pathway. Pentose phosphate oxidation. Fermentations: homolactic, heterolactic, alcoholic, mixed-acid, homoacetic. Aerobic and anaerobic respiration. Krebs cycle. Macromolecule catabolism.

Assimilative and biosynthetic metabolism. Key intermediates. Gluconeogenesis. Nitrogen assimilation. Sulfur assimilation. Phosphorus assimilation. Amino acid biosynthesis. Nucleotide biosynthesis.

Viruses. Viral structure, viral genetic material.


During the course, laboratory practicals will also be conducted by Dr. Lorenzo Nissen (2 ECTS).
The laboratory exercises provide an in-depth exploration of the topics covered during lectures and will include:

1) use of the optical microscope to observe the morphology of microbial cells from yeasts, bacteria, and molds
2) techniques for isolation, purification, and preservation of enological isolates
3) staining techniques for differentiating and highlighting microbial cell components: Gram staining, spore staining, and capsule staining
4) physiological tests and enzymatic reactions for the characterization of isolates: catalase, oxidase, Voges–Proskauer test
5) tests to assess the nutritional, oxygen, and temperature requirements of isolates
6)identification of microbial isolates
7)enumeration of cell cultures by direct and indirect methods: optical density, Thoma counting chamber, direct plate count
 8) evaluation of cell culture growth using plate inoculation techniques: pour plating and surface spread plating
9) analysis of experimental data: construction of growth curves and determination of growth phases in cell cultures

Readings/Bibliography

Madigan, M., Bender, K., Buckley, D., & Stahl, D. (2022). Brock Biology of Microorganisms: General, Environmental, and Industrial Microbiology. Pearson.

The teacher will also provide supporting materials for exam preparation. In fact, all the slides presented during lectures and practical laboratory exercises will be made available by the teacher on the Virtuale platform. See the VIRTUALE platform [https://virtuale.unibo.it ] (access restricted to students enrolled at the University of Bologna).

Teaching methods

Lectures and practical laboratory exercises. Where possible, seminars by industry experts will be held and guided tours of wineries will be organized.

The practical laboratory exercises will take place in the laboratories of the Food Science Campus in Cesena. These laboratories are equipped with state-of-the-art instruments and facilities, fully suited to achieving the specific learning objectives of the General Microbiology course.

Considering the type of activities and teaching methods adopted, attendance of this learning activity requires all students to complete Modules 1 and 2 in e-learning mode [https://www.unibo.it/it/servizi-e-opportunita/salute-e-assistenza/salute-e-sicurezza/sicurezza-e-salute-nei-luoghi-di-studio-e-tirocinio], as well as participation in Module 3, which provides specific training on health and safety in study environments. Information on the dates and attendance procedures for Module 3 can be found in the dedicated section of the degree programme website.

Assessment methods

The General Microbiology course is part of the Integrated Course General and Wine Microbiology, together with the Wine Microbiology course.

The assessment for the General Microbiology course will take place only at the end of the lectures and will consist of a final written exam structured in two parts: three open-ended questions, each worth up to 3 points, and 25 multiple-choice questions, each worth up to 1 point. The exam lasts 90 minutes, and consultation of books, notes, or other materials is not allowed. To pass the exam, students must score at least 18 points. A score of 33 points is awarded with honors (cum laude).

As this is an Integrated Course, please note that the recording teacher is Prof. Rosalba Lanciotti, and the final grade will be the weighted average of the two courses.

Exam sessions are scheduled within the official time windows defined by the degree program, and students may register for the exam exclusively through the Alma Esami online system. For further information on how to register, please visit: https://almaesami.unibo.it/almaesami/welcome.htm .

Students with learning disorders and\or temporary or permanent disabilities: please, contact the office responsible (https://site.unibo.it/studenti-con-disabilita-e-dsa/en/for-students ) as soon as possible so that they can propose acceptable adjustments. The request for adaptation must be submitted in advance (15 days before the exam date) to the lecturer, who will assess the appropriateness of the adjustments, taking into account the teaching objectives.

Teaching tools

PowerPoint presentations in electronic format available through the VIRTUALE platform [https://virtuale.unibo.it/ ] (access restricted to students enrolled at the University of Bologna) or via a shared folder reserved for students of the course.

Laboratories equipped with state-of-the-art instruments and facilities, fully suited to achieving the specific learning objectives of the course, are available for the practical exercises at the Food Science Campus in Cesena.

Office hours

See the website of Lorenzo Siroli

See the website of Lorenzo Nissen