Evaluation of Cynothece sp. ATCC 51142 as a candidate for inclusion in a CELSS

Controlled ecological life support systems, (CELSS) have been proposed to make long-duration manned space flights more cost-effective. Higher plants will presumably provide food and a breathable atmosphere for the crew. It has been suggested that imbalances between the CO sub(2) /O sub(2) gas exchange ratios of the heterotrophic and autotrophic components of the system will inevitably lead to an unstable system, and the loss of O sub(2) from the atmosphere. Ratio imbalances may be corrected by including a second autotroph with an appropriate CO sub(2) /O sub(2) gas exchange ratio. Cyanothece sp. ATCC 51142 is a large unicellular N sub(2) -fixing cyanobacterium, exhibiting high growth rates under diverse physiological conditions. A rat-feeding study showed the biomass to be edible. Furthermore, it may have a CO sub(2) /O sub(2) gas exchange ratio that theoretically can compensate for ratio imbalances. It is suggested that Cyanothece spp. could fulfill several roles in a CELSS: supplementing atmosphere recycling, generating fixed N from the air, providing a balanced protein supplement, and protecting a CELSS in case of catastrophic crop failure.