Biotechnology and Fermentation Basics

Overview

• Topic: Biotechnology and Genetic Modification (IGCSE Chapter 21, Part 1).
• Focus: definitions, common examples, role of microorganisms (especially bacteria and yeast), anaerobic respiration, products made by biotechnology, and fermenter operation.

Definitions

• Biotechnology: Using living organisms (bacteria, fungi, cells) to make useful products or solve problems.
• Genetic Modification: Altering an organism’s DNA to give specific traits or functions.
• Plasmid: Small circular DNA in bacteria used for gene manipulation in labs.
• Fermenter: Large, controlled vessel for growing microorganisms to produce products at scale.

Why Bacteria Are Widely Used

• Rapid reproduction enables fast production.
• Can synthesize complex molecules.
• Fewer ethical concerns compared to animals.
• Contain plasmids, which are easy to manipulate to add or modify genes.

Anaerobic Respiration in Yeast

• Yeast ferments sugar without oxygen to produce ethanol, carbon dioxide, and energy.
• Chemical equation: C6H12O6 → 2 C2H5OH + 2 CO2 (+ energy).
• Products used:
  • Ethanol for biofuels.
  • CO2 causes dough to rise in bread-making.

Examples of Biotechnology Products

• Biofuels (ethanol)
• Bread
• Fruit juice (improved extraction)
• Biological washing powders (enzyme-based)
• Lactose-free milk
• Pharmaceuticals and food products: insulin, penicillin, mycoprotein

Biofuels (Ethanol Production)

• Source: Plant material providing sugars.
• Process: Plant sugars mixed with yeast; yeast ferments sugars anaerobically to produce ethanol and CO2.
• Ethanol is harvested as a renewable fuel with lower harmful emissions.

Bread Production

• Ingredients: yeast, sugar, flour, water.
• Yeast ferments sugars anaerobically, producing CO2 and ethanol.
• CO2 forms bubbles trapped in dough, making bread rise and giving an airy texture.

Fruit Juice Production

• Pectin: molecule in plant cell walls that makes fruits thick and hard to extract.
• Pectinase enzyme: breaks down pectin, easing juice extraction and increasing yield.

Biological Washing Powders

• Contain enzymes analogous to digestive enzymes:
  • Protease breaks down protein stains (egg, meat, blood).
  • Lipase breaks down fats and oils (grease, butter).
• Benefits:
  • Convert insoluble stains to soluble molecules for easier removal.
  • Work well at lower temperatures, saving energy.

Lactose-Free Milk

• Lactose: milk sugar; some people are lactose intolerant.
• Lactase enzyme: breaks lactose into simpler sugars that are easier to digest.
• Adding lactase to milk produces lactose-free milk suitable for lactose-intolerant people.

Products Made in Fermenters

• Insulin: produced using bacteria; regulates blood sugar for diabetics.
• Penicillin: produced by the fungus Penicillium; an antibiotic that stops or kills bacteria.
• Mycoprotein: produced using fungi; protein-rich meat alternative.

Fermenter Control Conditions

• Temperature: affects reaction rates and microbial growth; must be optimal.
• pH: acidity/alkalinity influences microbial activity; maintained at preferred level.
• Oxygen: some microbes require oxygen; levels must match organism needs.
• Nutrient Supply: sugars, proteins, minerals controlled for optimal growth and production.
• Waste Removal: metabolic wastes must be removed to avoid inhibition of growth.

Key Terms and Definitions

Action Items / Next Steps (For Students)

• Review anaerobic respiration equation and label products and uses.
• Memorize examples of enzymes used in industry and their substrate targets.
• Understand why fermenter conditions (temperature, pH, oxygen, nutrients, waste) are critical for large-scale production.
• Prepare examples of biotechnology products and explain the microorganism and process involved.