Photosynthetic microbes use sunlight to break down organic matter via fermentation.
Technology
What is it?
Photosynthetic microbes use sunlight to break down organic matter via fermentation.
Why is it important?
Photo-fermentation could be used for producing hydrogen from wastewater or other organic waste with sunlight as an energy source.
Characteristics
- Inputs: Organic matter (hydrocarbons), water, sunlight
- By-products: Carbon dioxide
- Operating temperature: Ambient
- Energy efficiency: <10%
Benefits
- Low-to-net zero carbon
- Could be used in wastewater or water which cannot be used for drinking or agriculture
- Converts organic substrate
- Nearly complete substrate conversion into biohydrogen
- Can extract additional hydrogen from dark fermentation effluents
Limitations
- Large surface areas required
- Oxygen inhibits hydrogen production
- Operation variability depending on solar irradiation supply
- Less flexible than dark fermentation regarding the type of substrate
- It is usually necessary to convert complex substrates into a mixture of carboxylic acids and alcohols prior to H2 production by photofermentation
RD&D priorities
- Develop inexpensive photobioreactors
- Strain improvement through metabolic engineering
- Investigate replacement of nitrogenase with hydrogenase enzyme
- Overcome low hydrogen production rate
- Overcome low solar-to-hydrogen efficiency
- Reduce cost of photobioreactors
Known active organisations
- The Australian National University