Anaerobic photosynthetic bacteria have the capacity to produce significant amounts of H2 by using sunlight. This H2 can be produced either by hydrogenising or nitrogenising. The bacteria use reductant derived either from solar powered reactions or the oxidation of organic compounds to drive H2 production. By using sunlight and waste organic materials - for example sewage, agricultural or animal wastes - as electron donors to support the growth of bacteria and their subsequent generation of H2, these procedures will not only produce solar-powered H2 but have the added environmental benefit of treating and removing waste products in a carbon neutral process.

This is based on the following observations:

* purple photosynthetic bacteria, when illuminated, under N2 limiting conditions, produce significant amounts of H2, using nitrogenising.
* purple photosynthetic bacteria, when illuminated under N2 replete conditions, evolve to produce significant amounts of H2, using hydrogenising.
* since these bacteria are producing H2 without using O2, there are no significant problems of oxygen-sensitivity of the H2 producing process.

In order to develop this technology for H2 production, we need to:

* survey existing species/strains for H2 production under different conditions
* develop systems which maximize H2 production by isolated organisms or consortia
* investigate whether robust cell-free systems can be developed for light driven anaerobic H2 production
* investigate whether H2 can be efficiently converted into other fuels/energy sources
* develop the use of different sources of organic material to support light-driven H2 production
* investigate the basic biochemistry of the H2 evolution enzymes and use this knowledge to optimize H2 evolution under different environmental conditions
* understand microbial physiology in order to circumvent rate-limiting steps in solar powered H2 production.

This will allow development of new technologies for solar-powered H2 production by anaerobic photosynthetic micro-organisms. This will provide significant amounts of solar-derived H2 as a carbon-neutral replacement for fossil fuels. Since every household, farm and town continually produces large amounts of sewage or other waste material there are huge reserves of the required feed stocks to support this solar powered H2 production concept.

To achieve the goals outlined above, research is needed in the following general areas:

* selection of microbes or consortia for optimal solar-powered H2 production
* strategies to maximize activity of the enzymes that evolve H2 must be developed
* systems to selectively funnel reduction from the solar energy pathways and the oxidation of organic nutrient to the enzymes that produce H2
* strategies to either recycle or sequester the carbon locked up in the microbial biomass produced during solar-powered H2 production
* produce a working lab-based prototype for optimization with different microbes and feed stocks

We can then take the following steps;

* develop platforms to either trap the H2 for future use or for direct conversion into other fuels
* collaborate with engineers in order to scale up laboratory-based prototypes to the sizes needed to make this a scalable process of use to a range of users from single family farms to large towns