69153 - Biology Of Microrganisms

Learning outcomes

After this course, the student knows the structural, physiological and metabolic characteristics of the various microbial species and is able to manage and optimize the activity in the fermentative processes for the transformation of food raw material and to prevent the activity of pathogenic and toxinogenic microorganisms

Course contents

Introduction. What is microbiology and general descriptions. Difinition of microrganisms and importance of the microbiological heritage.

Bacterial classification. Phylogenesis. Methods for classification; genotype and phenotype. Definition of microbial species. Taxonomy of Bacteria: most important Phyla (Proteobacteria, Firmicutes, Actinobacteria). Characteristics of the main microbial groups: Pseudomonadacee, Enterobacteriacee, Acetobacteraceae, Acinetobacter and Chromobacterium, Vibrio e Photobacterium, lactic acid bacteria, Bacillus, Clostridium, Staphyilococci, Micrococci, Listeria, Corinebacteria, propionic bacteria, bifidobacteria.

Taxonomy of fungi: yeasts and moulds. Sexual and asexual reproduction among fungi: ascomycetes and basidiomycetes.

Structure of cells. Composition and functions of the microbial cells. Eukaryotic and prokaryotic cells: differences and common traits. Morphology and structure of microbial cells.

Microbial growth. Culture media: definition, classification, preparation. Microbial counting. Microbial growth curve: lag, exponential, stationary ans death phase. Diauxic growth. Chemostats. Homeostasis. Main factors able to influence growth curve: temperature, pH, aw and oxygen.

Nutrition and transport systems. Chemical component of cells. Energy (phototrophy, chemiotrophy, lithotrophy). Organic substance (autotrophy and organotrophy). Growth factors. Transport systems (primary, secundary group translocation).

Microbial metabolism. Energetic strategies. Fermentation and respiration. Electronic chain, redox potential and bioenergetics. Membrane carrier (NADH, quinones, cytochrome, Fe S proteins, flavoproteins). Proton Motive Force (PFM). ATP and CoA. Steps of the generation of PFM. ATPase

Energetic pathways. Glicolysis, Entner Doudoroff pathway. Oxidation of pentose phosphate. Fermentations: homolactic, heterolactic, alcoholic, mixed acid, butandiolic, acetic, butyric, propionic, homoacetic, bifidobacteria pathway, Stickland reaction. Aerobic and anaerobic respiration. Krebs cycle. Anapleorotic and glyossilic pathway. Catabolism of macromolecules.

Assimilative metabolism and biosynthesis. Key intermediate products. Gluconeogenesis. Calvin pathway. Nitrogen assimilation. Sulphur assimilation. Phosphate assimilation. Aminoacid biosynthesis, Nucleotide biosynthesis.

Bacterial genetic. Bacterial genome and nucleoid. Chromosome organization. Mobile genetic elements in bacteria. Plasmids, transposones, integrons, insertion sequences, viral genomes. Replication, transcription and translation of genetic information. Replication of chromosome: enzyme involved in replisome. Transcription: phases, mRNA role, sigma factor. Translation: tRNA, genetic code, protein synthesis, ribosome functions and characteristics. Role and function of operons. Regulation od transcription. Mutation and mutagenesis. Recombination, Horizontal genetic transfer: transformation, transduction and conjugation.

Virus: Viral structure. Genetic material in viruses. Steps of viral replication. Proteine virali. Bacterial viruses (fagi). Virulent fagi virulenti and temperate fagi. Characteristic of lysogenic fagi

Practical training in laboratory will be divided in several units:

Microbial growth curves: counting anddefinition of the different phases of the curve through direct (Burcker chamber, plate counting) and indirect (optical density) methods. Sampling of a food through plate counting (superficial or immersion inoculum).

Isolation of microorganisms: Purification and characterization of isolates. Optical microscope (cell morphology) and test of catalane. Fermentation trials. Gram staining: Gram: and Gram+ bacteri.

Molecular Methods for microbial identification

Readings/Bibliography

Brock. Biologia dei microrganismi. Microbiologia generale, ambientale e industriale. Pearson editor

Teaching methods

Theorical lessions and pratical laboratory course. If possible, seminars and lectures with experts in the field will be organized. Also guided tour in food industry, when possible, will be planned.

Assessment methods

The preparation of the students will be tested through a test with two types of questions. There are three open questions for each of which a maximum score of three points will be assigned. Then there are 25 multiple choice questions, for each of which a maximum of one points will be assigned. The time available to complete the test is 90 minutes. Text books, notes, and other tools are not admitted. The test is passed if a score of 18 points is reached. Score of 33 determines the obtaining of laude.

The final evaluation of the the course "Biology of Microorganisms and Food Inspection" is calculated as the arithmetic meas of the two units "Biology of Microorganisms" and "Food Inspection". Because it is an integrated course, the final score will be registered by Prof. Gerardo Manfreda

Teaching tools

Slides and seminars

Office hours

See the website of Francesca Patrignani