We have developed an automated high-sensitive ATP bioluminometer for detecting single bacterium. The apparatus consists of a tube rack for setting reagents and samples, two washing baths for preventing sample carry-over from dispenser nozzle, and x-, y-, z- actuators for moving the dispenser, and an high-sensitive optical system. The reaction tube was selected to reduce the background signal intensities for the ATP bioluminescence measurement. The background signal intensity of the reaction tube was 18 RLU, which is almost the same as the dark counts of the photomultiplier (16 RLU). The ATP calibration curve was linear from 0 to 5 amol (its slope = 22.4 RLU/amol and 3.3 SD of the blank sample signal = 17.9 RLU), and the detection limit of 0.8 amol was obtained. The relationship between intracellular ATP and CFU in Escherichia coli (ATCC25922) was kept linearity from 0 to 20 CFU, and the intracellular ATP (amol) per CFU was calculated to be 3.3 amol/CFU (R2 = 0.9713). Moreover, the relationship between intracellular ATP and CFU in Staphylococcus aureus (ATCC25923) was also kept linearity from 0 to 30 CFU, and the amol/CFU was calculated to be 1.6 amol/CFU (R2 = 0.9847). The automated ATP bioluminometer has ultra-high sensitivity and will be a powerful tool for measuring ATP luminescence derived from small number of bacteria.

The "Group Combustion" experiment is planned as the first combustion experiment in the KIBO on the ISS. Flame spread characteristics of n-decane droplet clouds and linear array will be investigated in detail. The experiment will employ the Multipurpose Small Payload Rack (MSPR), the Chamber for Combustion Experiment (CCE), and the Group Combustion Experiment Module (GCEM) as experimental apparatus. At present, development of the GCEM has been ongoing in parallel to detail planning of the experiment operation onboard the KIBO. In this paper, current status on preparation of the experiment will be introduced.

For demonstration of the upgraded microgravity experimental system by the balloon operated vehicle, combustion experiment of fuel droplet array has been prepared. Development of the experimental apparatus is completed and preparation toward execution of the flight experiment in 2013 is proceeding. In this paper, overview of the experiment and the latest status will be explained with emphasis on scientific aspects of combustion research.