Piousbox

The Methane, Alcohol, and Butane Energy Cycle Using Algae, Yeast, and Bacteria

This bioenergy cycle explores how microorganisms—algae, yeast, and bacteria—can work together to produce renewable fuels like methane, ethanol (alcohol), and butane. These biofuels can be created in a closed-loop system that recycles waste and maximizes energy extraction.

1. Algae Stage – Carbon Fixation and Biomass Production

• Algae (e.g., Chlorella, Spirulina) absorb CO₂ and sunlight through photosynthesis.
• They grow rapidly, producing biomass rich in carbohydrates, lipids, and proteins.
• This biomass becomes the feedstock for the next stages.

2. Yeast Fermentation – Alcohol (Ethanol) Production

• Yeast (e.g., Saccharomyces cerevisiae) is used to ferment the carbohydrate-rich portion of the algae biomass.

• The process converts sugars into ethanol and CO₂:

   

  C6H12O6 → 2 C2H5OH + 2 CO2

• Ethanol can be used directly as biofuel or further processed.

3. Bacterial Digestion – Methane and Butane Production

• The leftover biomass and organic waste from fermentation are fed into an anaerobic digester containing methanogenic bacteria (e.g., Methanobacterium).
• Bacteria break down the material into biogas, a mixture of:
  • Methane (CH₄)
  • Carbon dioxide (CO₂)
  • Trace gases
• Under specific conditions, butane or butanol can also be produced via Clostridium species in an ABE fermentation (Acetone-Butanol-Ethanol).

Energy Integration Cycle

1. Sunlight & CO₂ → Algae biomass
2. Algae sugars → Ethanol (via yeast)
3. Fermentation waste → Methane & Butane (via bacteria)
4. CO₂ released → Recycled by algae

This forms a low-waste, renewable, and carbon-neutral cycle, ideal for sustainable energy systems.