**Group 1: Fermentation Overview**
– Definitions and etymology of fermentation
– Preservation methods for food using microorganisms
– Large-scale microbial processes with or without air
– Production of alcoholic beverages or acidic dairy products
– Energy-releasing metabolic processes under anaerobic conditions
– Biological role: extracting energy from molecules, common to all bacteria and eukaryotes, conversion of sugar-rich molecules to ethanol and carbon dioxide, role in methane production
– Biochemical overview: involving NADH and organic electron acceptors, production of ethanol, lactic acid, hydrogen gas, and exotic compounds like butyric acid and acetone
– Products of fermentation: ethanol, use in bread dough rising, intoxicating agent in alcoholic beverages, production from feedstocks like sugarcane and maize, energy provision in fish during oxygen scarcity
**Group 2: Specific Fermentation Processes**
– Lactic Acid Fermentation: production of lactic acid, conversion of lactose into lactic acid in yogurt, conversion of lactate to ethanol and carbon dioxide, conversion of lactic acid to ethanol, production of acetic acid from lactic acid
– Hydrogen Gas Production: generation of hydrogen gas to regenerate NAD, involvement in various fermentations like butyrate, acetate, and hydrogen gas production, high hydrogen gas concentration in some cases
– Other Types of Fermentation: mixed acid, butanediol, butyrate, caproate, and glyoxylate fermentations with specific end products and metabolic pathways, serving different biological and industrial purposes, aiding in biotechnological applications, expanding knowledge
**Group 3: Industrial Fermentation Operations**
– Modes of Industrial Operation: batch or fed-batch procedures, challenges in continuous fermentation, addition of chemicals for pH control or foaming suppression, phases in batch fermentation
– Batch Fermentation: used for bread and alcoholic beverages, sterilization requirements, pH control, and foam suppression, phases include lag, exponential growth, stationary, and death phases
– Fed-batch Fermentation: variation of batch fermentation with added ingredients during the process, control over stages, optimization of production of secondary metabolites
– Open Fermentation: resistance to contamination, use of mixed cultures, applications in solid-state fermentation, production of lactic acid by thermophilic bacteria, bioplastics by halophilic bacteria
– Continuous Fermentation: continuous addition of substrates and removal of final products, varieties like chemostats, turbidostats, and plug flow reactors, avoidance of setting up batches repeatedly, prolonging exponential growth phase
**Group 4: Historical and Modern Significance of Fermentation**
– Development of Fermentation Technologies: advancements in the 1950s and 1960s, importance in bulk chemicals production in the 1970s and 1980s, interest in functional foods in the 1990s and 2000s, use of genetically engineered microorganisms and probiotics
– Advancements in Industrial Fermentation: progress from the 1930s onward, global production of fermented products, utilization for industrial purposes, increased production of high-value products, precise control over fermentation processes
– Applications of Fermentation: industrial enzyme applications, open and continuous fermentation processes, modeling, monitoring, and control of batch fermentation, bioprocess economy, fermented beverages in ancient China and wine fermentation studies
**Group 5: Cultural and Scientific Perspectives on Fermentation**
– Importance of Fermentation: essential role in global food production and preservation, production of beverages like beer and wine, development of unique flavors and textures in food
– Historical Significance: contributions of Louis Pasteur and Eduard Buchner, centuries-old practice in various cultures, rich history of indigenous fermented foods, evolution of the physiological theory of fermentation
– Scientific Insights: role of metabolic pathways, connection to cellular respiration, involvement of different microorganisms, complexity of fermentation processes
– Cultural Perspectives: integral role in traditional cuisines, variations in fermentation techniques across cultures, symbolic significance in rituals and celebrations, diversity contributed by indigenous knowledge, transmission of fermentation traditions through generations
– Modern Applications: utilization in pharmaceutical, biotechnological, biofuel, and cosmetic industries, ongoing research uncovering new applications in diverse fields
Fermentation is a metabolic process that produces chemical changes in organic substances through the action of enzymes. In biochemistry, it is broadly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food production, it may more broadly refer to any process in which the activity of microorganisms brings about a desirable change to a foodstuff or beverage. The science of fermentation is known as zymology.
In microorganisms, fermentation is the primary means of producing adenosine triphosphate (ATP) by the degradation of organic nutrients anaerobically.
Humans have used fermentation to produce foodstuffs and beverages since the Neolithic age. For example, fermentation is used for preservation in a process that produces lactic acid found in such sour foods as pickled cucumbers, kombucha, kimchi, and yogurt, as well as for producing alcoholic beverages such as wine and beer. Fermentation also occurs within the gastrointestinal tracts of all animals, including humans.
Industrial fermentation is a broader term used for the process of applying microbes for the large-scale production of chemicals, biofuels, enzymes, proteins and pharmaceuticals.