[12]

DEVELOPMENT OF A SHORT-TERM BIOASSAY TO EVALUATE PHOTOXICITY OF BIOREACTOR EFFLUENT.  Peter K. Cudjoe¹, and Dr. Richard F. Strayer².  ¹Tuskegee University, Tuskegee, Alabama, and ²Dynamac Corporation, Kennedy Space Center, Florida.

     In order for humans to inhabit space there must be an adequate supply of food.  Whenever food is consumed there are waste products by means of human expulsion or inedible plant parts. The fixed film bioreactor (FFB) was used to produce a nutrient solution from plant waste, in order to feed back to plants.  Our objective was to develop a short-term (22 days) plant growth bioassay to test the effluent from the FFB (hydraulic retention time = 6 hr), currently under development.  The nutrient solution (effluent) was tested against a modified Hoagland’s solution, a nutritionally balanced medium that is currently being used for plant growth experiments.   We tested the effluent on three different plant species, each with different chemical tolerances. The effluent was expected to produce a yield similar to that of the Hoagland’s. The dry weight data showed that plants treated with Hoagland’s and FFB effluent had similar weights. The ranges of dry weight were 0.2g to 0.3g for wheat, 0.40g to 0.50g for radish, and 0.20g to 0.30g for lettuce. Results for some of the other plant growth parameters (plant height and leaf area) were somewhat ambiguous and unexpected, in relation to the dry weight results. 

     (Supported by NASA’s Spaceflight and Life Sciences Training Program)