Utilization of the Space Station Detergent IGEPON by a Candidate Organism for Use in a Space Biological Waste Reactor

The microgravity environment of space introduces a major new variable for consideration that will affect the design and operation of bioreactors. Adequate aeration for aerobic bioreactors will be a challenge as will gas/liquid separation, removal of carbon dioxide and other bacterial metabolic waste products, control algorithms, and overall performance assessment. These challenges must be addressed in order to fully assess the efficacy of biological approaches to the recovery of potable water from wastewater in microgravity. The first step in this process is to define the fermentation parameters of the organism or consortia that will be used in these space bioreactors.

This study was designed to investigate the ability of bacteria to degrade the space station detergent IGEPON. The ultimate goal was to define the growth conditions required by an IGEPON-utilizing bacteria, so that these conditions could be used in a flight experiment designed to prove the concept of biological waste conversion. To this end, we isolated an Acinetobacter calcoaceticus (JSC 96121) that could use IGEPON and defined its requirements for growth. The growth conditions required for the batch utilization of IGEPON by JSC 96121 were: excess oxygen levels; a temperature of 25 to 35°C; a pH 6.0 to 8.0; 40 to 60 g/L IGEPON; 0.225 g/L NH₃⁺; and 1.36 g/L PO₄. JSC 96121 utilization of IGEPON did not require vitamins or cofactors. Other required inorganic salts could be supplied by tap water.