BTEC Level 2 – Applied Science & Microbiology | Anaerobic respiration by microorganisms
Fermentation is a metabolic process that converts sugars (like glucose) into acids, gases, or alcohol without using oxygen (anaerobic conditions). It allows microbes such as yeast and bacteria to generate energy (ATP) when oxygen is absent.
Glucose → Ethanol + Carbon dioxide + ATP (energy)
C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂ + 2 ATP
Real-world examples: Bread making (CO₂ makes dough rise, ethanol evaporates), beer, wine, biofuels.
Glucose → Lactic acid + ATP
C₆H₁₂O₆ → 2 CH₃CHOHCOOH + 2 ATP
Examples: Yoghurt, cheese, sauerkraut, sourdough bread (tangy flavour). No CO₂ produced in this type (except some heterofermentative strains).
Bioreactors control temperature, pH and anaerobic conditions to maximise yield of ethanol or lactic acid. Quality control includes checking pH, gas production, and microbial counts.
🎥 Video 1: What happens when you can't do aerobic cellular respiration because oxygen isn't available? Explore fermentation with The Amoeba Sisters! This video focuses on alcoholic fermentation and lactic acid fermentation, and also mentions how this pathway is different from anaerobic cellular respiration. Watch the full explanation from 00:00 to 6:35 to understand the key differences between alcoholic and lactic acid fermentation.[reference:0]
🎥 Video 2: This video breaks down the chemical pathways of lactic acid and alcoholic fermentation, highlighting how each process is used in food production and biotechnology. Compare the inputs, outputs, and energy yields of both fermentation types.[reference:1]