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Questions and Answers
What is the primary effect of high glucose concentrations on facultative fermenting microorganisms?
At what glucose concentration does S. cerevisiae demonstrate the Crabtree effect?
During which phase in the biomass propagation process do cells experience high sugar concentrations?
What is necessary to adjust in the fermentor during the biomass propagation process?
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Which of the following processes is inhibited due to the Crabtree effect?
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What is one of the main products obtained from microbial biomass?
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Which organism is primarily used in the QuornTM process for protein production?
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What ingredients are mixed with the mycoprotein in the QuornTM process for vegan products?
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What type of fermentation process is employed in the production of microbial biomass under controlled conditions?
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What is a key component of the substrates used in microbial fermentation?
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Which mineral salts are commonly included in the substrates for microbial biomass fermentation?
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How is the mycoprotein processed after fermentation in the QuornTM production?
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Which of the following statements about microbial biomass is incorrect?
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What phase follows when ethanol is exhausted in the yeast biomass propagation process?
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Which factor is primarily used to control the growth rate profile during fed-batch cultivation?
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What is the optimal pH level to maintain during the fed-batch phase?
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Why is controlling the temperature important during fed-batch cultivation?
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What effect does an increase in the specific growth rate have on biomass productivity?
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What is the ideal temperature to maintain during the fed-batch phase?
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Which parameter is NOT critical to optimize biomass productivity during fed-batch cultivation?
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What is the purpose of optimizing the biomass yield during the fed-batch phase?
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What are the primary substrates used in yeast production?
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Which essential element is mentioned as being poor in molasses?
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What sugars are primarily found in molasses?
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What must be supplemented for fast yeast growth when using molasses?
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What is the Pasteur effect related to?
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What is a potential negative factor impacting yeast growth from molasses?
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What process does yeast use to convert sucrose into glucose and fructose?
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Which of the following is not a characteristic of molasses?
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What role does the presence of O2 play in yeast fermentation?
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Which phase occurs at the beginning of batch fermentation?
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What happens when the sugar concentration drops below a specific level during fermentation?
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What is a consequence of the Crabtree effect during fermentation?
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What is one characteristic of the exponential phase in yeast fermentation?
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Which phase follows the growth lag phase in batch fermentation?
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What is the primary purpose of accumulating reserve metabolites during fermentation?
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In what type of metabolism does the alcohol fermentation process generally result?
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What does the fermenting power indicate in the context of Oenological properties?
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Why is high volatile acidity considered undesirable in fermentation?
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Which factor is crucial for achieving optimal fermentation temperature?
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What is the implication of selected strains releasing more than 100-400 mg/L of CO2?
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What characteristic of a yeast strain is indicated by high fermenting vigor?
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In the context of SO2 tolerance and production, what is a desirable attribute for yeast strains?
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What outcome does high foam production indicate during fermentation?
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What happens to yeast growth mode during the fermentation process if rapid sedimentation occurs?
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Study Notes
Microbial Biotechnology - General Aspects
- Microbial biotechnology has ancient roots, especially in traditional food processing
- Identifying, selecting, cultivating, and preserving microorganisms (like starters) is fundamental to modern biotechnology
- A Sumerian clay tablet (c. 4000 BC) documents beer brewing, indicating early microbial use
- Barley and spelt were ground, soaked, heated, filtered, and fermented with honey and spices to make ancient beer
- In 1860, Louis Pasteur demonstrated that fermentation is a microbial process, not chemical
- He showed that yeast can survive and multiply in the presence or absence of oxygen
- Later in 1883, Emil Christian Hansen used pure yeast cultures to improve beer brewing, a significant advancement
- The first industrial yeast production was in Austria, 1867
- In 1872, the first grain yeast factory was founded in France
Biotechnology Products - Microbial Biomasses
- Microbial biomass is a readily accessible category of biotechnological product
- Primary use is for animal feed and human dietary supplements
- Biomass contains proteins, vitamins, and minerals
- It can be derived from agro-industrial byproducts or agricultural surplus
- Various organisms, including bacteria, yeasts, molds, and algae, are sources of biomass, with varying protein content
- Quorn™ is a protein source alternative to meat, created from a specific fungus (Fusarium venenatum), combined with other nutrients
- Cellular lysates, enzymes, lipids, nucleic acids, and their derivatives are also extracted from microbial biomass for food and pharmaceuticals
Biotechnology Products - Primary Metabolites
- Primary metabolites are crucial for cell growth and reproduction
- Extracted and purified from the cell into culture media
- Often result from anaerobic metabolism (e.g., lactic acid from Lactobacillus, propionic acid from Propionibacterium, butyric acid from Clostridium)
- These compounds are accumulated in significant amounts. Lactobacillus delbrueckii ssp. bulgaricus produced 130 - 140 g L⁻¹ of L-lactic acid
- Polylactic acid (PLA) - A polymer produced from lactic acid and is thermoplastic, biodegradable, and compostable
- It is used in various applications including fibers, clothing, and food packaging
Biotechnology Products - Secondary Metabolites
- Secondary metabolites have diverse biological activities (e.g., antimicrobials, immunomodulators, antitumor agents)
- Antibiotics are notable examples of secondary metabolites, often obtained from bacteria or fungi
- Statins, with cholesterol-lowering activity, are commercially essential secondary metabolites, derived from certain fungi (e.g., Aspergillus terreus, Monascus species)
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Description
Explore the fascinating history and fundamental principles of microbial biotechnology. From ancient beer brewing practices in Sumer to Louis Pasteur's discoveries, this quiz highlights key concepts and milestones in the field. Learn about the importance of microorganisms in food processing and biotechnological applications.
