Agricultural and wine microbiology (2020/2021)

Course code
4S003186
Credits
12
Coordinator
Sandra Torriani
Teaching is organised as follows:
Unit Credits Academic sector Period Academic staff
MICROBIOLOGIA AGRARIA 6 AGR/16-AGRICULTURAL MICROBIOLOGY See the unit page See the unit page
MICROBIOLOGIA ENOLOGICA 6 AGR/16-AGRICULTURAL MICROBIOLOGY See the unit page See the unit page

Learning outcomes

The aim of this course is to provide, across the two modules, detailed knowledge concerning:
- the structure, physiology, biochemistry, genetics and ecology of microorganisms, with a particular emphasis on those relevant for the viti-viniculture chain, with the aim of understanding the strategies for their growth and survival and how to avoid uncontrolled proliferation.
- the biotechnological aspects of fermentation and transformation of must and wine, and on the microbiological stability of the final product. These skills are of great importance to understand, manage, and optimize the activities of yeasts and bacteria in relation to the characteristics of the must and the wine to be obtained, as well as of the productive process applied.

Syllabus

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MM: MICROBIOLOGIA AGRARIA
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------------------------ MM: Teoria ------------------------ Short history of microbiology. Introduction on identity and distribution of microrganisms in the vitiviniculture chain. The cell: general concepts, distinction between prokaryotes and eukaryotes. Morphology and cytology of the microbial cell. Structure and functions of the prokariotic cell: cell wall, capsule, flagella, cytoplasmic membrane, cytoplasm, organelles, ribosomes, reserve substances, bacterial genomes. The bacterial spore. Microbial nutrition. Cultivation techniques, selection and isolation techniques. Microorganisms and environment: responses to temperature variation, oxygen, pH and water activity. Microbial growth kinetics. Control of microorganisms by physical and chemical agents. Microbial metabolism. Aerobic and anaerobic respiration. The main fermentations. Genetics of microorganisms. Genetic information in bacteria: bacterial chromosome, plasmids and transposons. Mutations: selection and identification of mutants. Horizontal transfer of gene information between bacteria: transformation, conjugation, transduction. Production of bacterial recombinants. The viruses. Bacteriophages: lithic cycle and lysogenic cycle. Classification of micro-organisms. The concept of species. Traditional and molecular taxonomy. Groups of microorganisms. Techniques for the analysis of microbial diversity and their application in the study of ecosystems relevant for the viticulture and oenology. ------------------------ MM: Laboratorio ------------------------ The activities will include participation in the preparation of experiments, including safety instructions. Preparation of solutions and culture media, observation under a microscope, staining (e.g., Gram staining for bacteria), preparation of serial dilutions, plating on solid media to determine colony forming units of a microbial culture. Moreover, tests will be carried out to characterize microorganisms, such as the determination of the physiological profile (API tunnels), the verification of the ability to produce gas and the presence of catalase activity of isolates deriving from pure cultures of microrganisms.
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MM: MICROBIOLOGIA ENOLOGICA
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------------------------ MM: Teoria ------------------------ The microorganisms of oenological interest: yeasts and bacteria in winemaking. The yeasts: classification, metabolism, reproduction, genetics. The must as a substrate for microbial development. The alcoholic and malolactic fermentations. The principal and secondary products of fermentation. The lactic acid bacteria: definition and classification. The malolactic fermentation: effects on the sensory characteristics and the wholesomeness of wines. Other microorganisms of oenological interest: acetic acid bacteria and mould. Wine spoilage of microbial origin. Definition and characteristics of spoilage microorganisms. Production of biogenic amines, etilcarbammate and ochratoxin. Microbial ecology: the spontaneous fermentation of grape must. The controlled fermentations. Starter cultures of yeasts and malolactic bacteria for wine. Clonal selection of yeasts, genetic improvement, selection of technological and qualitative characteristics, autolytic capacity. Clonal selection of malolactic bacteria, selection of technological and qualitative characteristics. Use of microbial inoculants in oenology. Working conditions, induction / arrest of alcoholic fermentation. Microbial interactions and wine quality. Methods for the isolation, identification and technological characterization of yeasts and malolactic bacteria. Traditional methods. Direct and indirect rapid methods. Molecular techniques. ------------------------ MM: Laboratorio ------------------------ The aim of the laboratory is to provide the knowledge to the student the main techniques used for isolation and identification of yeasts and bacteria through assays based on morphological and physiological, and molecular assays. In detail, isolation using general purpose and differential media, applied microscopy, microbial analysis of wine yeasts/bacteria starters, physiological and technological tests, genetic typing, microvinification trials. ------------------------ MM: Laboratorio ------------------------ The aim of the laboratory is to provide the knowledge to the student the main techniques used for isolation and identification of yeasts and bacteria through assays based on morphological and physiological, and molecular assays. In detail, isolation using general purpose and differential media, applied microscopy, microbial analysis of wine yeasts/bacteria starters, physiological and technological tests, genetic typing, microvinification trials.

Assessment methods and criteria

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MM: MICROBIOLOGIA AGRARIA
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------------------------ MM: Teoria ------------------------ The exam aims to verify the skills and knowledge acquired in the context of the topics addressed during the lectures and laboratory activities. The verification of learning, both for attending students and non-attending students, will be carried out at the end of the module through an oral exam based on questions and excercises related to the laboratory experience. There will also be the possibility, for each student, to deliver, at the time of registering for the exam, a report on the practical exercises carried out in the laboratory; this report will be associated with a maximum score of 2 points. The exam in Agricultural and Oenological Microbiology must be considered passed if a score of at least 18 is reached in each of the two modules and the overall grade is determined as the arithmetic average of the evaluations obtained in each module. ------------------------ MM: Laboratorio ------------------------ ------------------------ MM: Laboratorio ------------------------
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MM: MICROBIOLOGIA ENOLOGICA
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------------------------ MM: Teoria ------------------------ The assessment of learning, for both attending and non-attending students, will be done at the end of the module through a written test of approximately 75 minutes, during which text books, notes, and other tools are not admitted. The test consists of 8 open questions for each of which a maximum score of 2 points will be assigned, and 20 multiple choice questions, each associated with a maximum of 1 point. The examination will be considered positive if at least 18 points will be assigned to the candidate. To gain access to the test, at least the previous day of the test, the candidate must submit a report on the practical activities carried out in the laboratory; this report will have a maximum score of 2 points. Scores higher than 31 will result in the "laude". It is possible to view the performed test and ask for clarification. In case the written test is not passed, or in case of sanitary emergency, the assessment of learning will be carried out with an oral exam which consists of three or four questions posed to each candidate. The exam lasts about 30 minutes. Both written and oral examinations are aimed to assess and verify the skills and knowledge acquired in the issues addressed throughout all the course program. Attendance to the practical activities is mandatory to be admitted to the examination. The course of Agricultural and Wine Microbiology will be considered positive if the score of at least 18 points will be reached in both the modules and the final score will derive from the arithmetic mean of the scores obtained in the two modules. ------------------------ MM: Laboratorio ------------------------ At the end of the practice lessons the student should be draw up a report on the activity carried out in laboratory. The manuscript will be discussed during the test. ------------------------ MM: Laboratorio ------------------------ At the end of the practice lessons the student should be draw up a report on the activity carried out in laboratory. The manuscript will be discussed during the test.

Reference books
Author Title Publisher Year ISBN Note
Gianni Dehò e Enrica Galli (a cura di) Biologia dei Microrganismi (Edizione 3) Casa Editrice Ambrosiana 2018 978-8-808-18623-2
Michael Madigan, John Martinko, Kelly Bender, Daniel Buckley, David Stahl BROCK Biologia dei microrganismi - Microbiologia generale, ambientale e industriale (Edizione 1) Pearson Italia 2016 889190094X
Suzzi G. & Tofalo R. Microbiologia enologica (Edizione 2) Edagricole 2018 978-88-506-5557-1