Agricultural Microbiology MCQ Exam - MICR20010

Agricultural Microbiology - MICR20010

• Course code: MICR20010
• Course name: Agricultural Microbiology
• Instructor: Dr. Tadhg Ó Cróinín

Practical MCQ Exam

• Exam date: Friday, Nov 22nd
• Exam time: 2:00 PM - 3:00 PM
• Exam format: Practical Online MCQ
• Instructions: Sample questions are available on Brightspace; refer to the e-mail for specific instructions. Separate e-mails for DSS students.
• Additional resources: Sample MCQ questions for the final exam in RDS are also available on Brightspace.

Remaining Lectures

• Lecture 10: Microorganisms and Disease
• Lecture 11: The Immune System
• Lecture 12: Pathogenic Bacteria
• Lecture 13: Pathogenic Fungi and Viruses
• Lecture 14: Antibiotic-Resistant Microorganisms
• Lecture 15: Microbiology in the Food Industry (including The Fungi)
• Lecture 16: Microbiology in the Food Industry (Fermentations)
• Lecture 17: The Nitrogen Cycle

Single Cell Protein (SCP)

• History: Originated in WWII to produce protein inexpensively using S. cerevisiae and Candida utilis.
• Development: Rapid growth in the 1960s and 1970s, resulting in the term "SCP".
• Application: Primarily used for animal feed, not widespread for human consumption.
• Production methods: Yeast from whey or Quorn production.

Production of Yeast Biomass

• Essential for high yield: Aeration is crucial to prevent fermentation.
• Affordable media: Historically, cereal grains; now mainly molasses.
• Gradual scale up: Transition from bench-top cultures to fermenters.
• Specialized feeding regimes: Necessary to avoid fermentation (fed-batch).
• Ripening stage: To encourage trehalose production and reduce protein production.
• Processing: Centrifugal separators before washing, drying, and packaging.

Yeast Production Process

• Stages: Stock culture, sterile medium, flask culture, seed culture, intermediate fermentor, production fermentor, concentration washing, cool storage, dewatering, compressing, packaging, cold storage.

Characteristics of Good Baker's Yeast

• High growth rates
• Good storage properties (including cryotolerance)
• Osmoresistance (to function in dough)
• Rapid maltose utilization (main dough sugar)
• High glycolytic activity ("gassing power")

SCP Production Methods

• Sources: Algae (spirulina), fungi, bacteria
• Methods: Submerged fermentation and solid-state fermentation
• Post-fermentation steps: Harvesting, washing, disrupting biomass, extracting protein.

Substrates for Microorganism Production

• Algae: CO₂ and sunlight
• Fungi: Waste materials providing carbon and nitrogen
• Bacteria: Industrial wastes or byproducts
• Specific examples: Molasses from sugar manufacture/starch hydrolysis, spent sulphite liquor, acid hydrolysates of wood, agricultural wastes, methane, methanol + ethanol, gas oil.

Nutritional Value of Microorganisms

• Algae: High in protein (40-60%), fats, vitamins (A, B, C, D, E), and minerals (7%).
• Fungi: Rich in B-complex vitamins, balanced amino acids (e.g., A. niger), thiamine, riboflavin, and biotin (in yeast).
• Bacterial SCP: High protein content, specific essential amino acids (e.g., methionine).

SCP Limitations

• Algal SCP: Cell walls are difficult for human digestion, production is weather-dependent.
• Fungal SCP: Potential for mycotoxins.
• Bacterial SCP: Expensive to produce, possible accumulation of uric acid (kidney stones, gout).

SCP in Nutrition and Food Production

• Application: Source of human and animal feed.
• Acceptable species (microorganisms): Saccharomyces cerevisiae, Candida utilis, Chlorella species
• Example: Quorn myco-protein, Fusarium graminearum species.

Mushrooms

• Types: Filamentous fungi forming fruiting bodies; edible varieties, like Agaricus bisporus (button mushroom), Lentinus edodes, Pleurotus spp (oyster mushroom) ~12,000 fungi species.
• Production process: Liquid culture inoculum preparation, bed preparation (composting), inoculation into compost, mycelial growth (25°C for 2-3 weeks), casing layer application (peat), fruiting bodies over ~4-6 weeks (multiple flushes).
• Benefits: Cheap to produce, excellent source of protein, easily harvested.
• Medicinal uses: Extracts from specific genera (e.g., Auricularia, Flammulina, Ganoderma, Hericium) are used immunomodulators, anti-cancer, and as a source for rare minerals/amino acids. Problems: Mycotoxins.
• Mycotoxins are secondary metabolites; some species produce mycotoxins which harm humans and animals. Examples include Aspergillus and Fusarium. Specific cases include Alflatoxins, first discovered in 1960 when 100,000 turkey poults died, and 14,000 ducklings died suddenly.

Additional Information

• Upcoming exam (Microbiology in the Food Industry - Alcohol, Dairy Industry, Vinegar): Next Monday.
• Previous exam reminder: Online Practical MCQ exam on Friday at 2 pm.

Prepare for the Agricultural Microbiology practical MCQ exam with this quiz. Cover essential topics including microorganisms and disease, the immune system, and antibiotic-resistant microorganisms. Make sure to review sample questions on Brightspace as you get ready for this important assessment.