BIOLOGY OF MICROORGANISMS IN ENOLOGY

Knowledge and understanding: Upon completing the course, students will acquire knowledge of the fundamental characteristics of prokaryotic and eukaryotic microbial cells, their nutritional requirements, and the factors influencing their growth, alongside the principles of traditional microbiological techniques. Students will understand the physiological and ecological rationale for managing and controlling alcoholic and malolactic fermentations (both spontaneous and guided via pro-technological starter cultures), as well as the mechanisms underlying undesirable fermentations and microbial spoilage.

Applying knowledge and understanding: Managing fermentation processes and preventing undesirable microbial spoilage.

Making judgements: Interpreting microbiological analytical data and selecting corrective interventions in the winery.

Communication skills: Using correct scientific and technical terminology to describe microbiological phenomena

Learning skills: Accessing and reviewing domain-specific scientific literature for autonomous lifelong learning.

Face-to-face lectures (42 hours) and exercise sessions (42 hours; individual or group activity). 

If the course is delivered in blended or remote mode, appropriate adjustments may be made to the above, in order to ensure consistency with the syllabus

• Fundamentals of biology are useful for this course

Attending the classes is not mandatory, but strongly recommended, as it facilities the learning process and contributes to the achievement of the learning objectives.

The course first addresses the fundamentals of general microbiology, analyzing the morphology, structure, and differences between prokaryotic and eukaryotic microbial cells. Subsequently, it examines the nutritional requirements and environmental parameters that influence microbial growth, alongside the main traditional microbiological techniques for cultivation and isolation. In the second part, the course focuses on the management and control of alcoholic and malolactic fermentations, comparing spontaneous processes with guided ones based on the application of pro-technological microorganisms used as starter cultures. Finally, the program covers undesirable fermentations, exploring the dynamics leading to microbial spoilage and the relevant prevention strategies.

2. Romano P., Ciani M., Cocolin L. Microbiologia  della vite e del vino. Casa Editrice Ambrosiana

·         What are the main structural differences between a prokaryotic cell and a eukaryotic cell?

• ·         Which physicochemical and environmental factors mostly influence microbial growth (pH, temperature, nutrient availability, $\text{SO}_2$)?

  ·         What is meant by culture medium, and what are the main methods for counting and isolating microorganisms in the laboratory?

  ·         Metabolism of Saccharomyces cerevisiae (Crabtree effect and Pasteur effect)

  ·         Which non-Saccharomyces species are of enological interest?

  ·         What are the main differences between a spontaneous and a guided alcoholic fermentation?

  ·         Besides ethanol and carbon dioxide, what are the main secondary products of alcoholic fermentation, and how do they influence the organoleptic profile of wine?

  ·         Which bacteria are responsible for malolactic fermentation in wine, and what are their physiological features?

  ·         Under which conditions is it advisable to promote malolactic fermentation, and when is it appropriate to prevent or block it?

  ·         What are the critical issues or unwanted secondary products linked to lactic acid bacteria metabolism (e.g., biogenic amines, diacetyl, volatile acidity)?

  ·         The genus Brettanomyces/Dekkera: which volatile compounds does it produce, and how can it be controlled in the winery?

  ·         What are acetic acid bacteria, which metabolic pathway do they use, and how can acetic spoilage be prevented?

  ·         What are the main bacterial spoilages of wine, and what causes them?