Abstract: The present invention relates to recombinant microorganisms for producing biological hydrogen. In addition, the invention relates to nucleic acid constructs and processes for modifying microorganisms for enabling the production of hydrogen therefrom.

Abstract: The present invention provides isolated nucleic acids encoding Ch1 d synthase, gene constructs comprising the isolated nucleic acids and cells, chloroplasts, plant tissue and whole plants ectopically expressing cyanobacterial Ch1 d synthase. The invention also provides isolated antibodies prepared using recombinant Ch1 d synthase. The antibodies and gene constructs of the invention are used to produce Ch1 d in organisms that do not normally produce Ch1 d, and to modify Ch1 d level in cyanobacterial cells, such as for modifying environmental host range and photosynthetic capacity of organisms in low light and/or red or far-red or near far-red light environments.