Using membrane reactor integrated with water vapor permselective membrane, the Sabatier reaction for the methanation of carbon dioxide with hydrogen, CO₂+4H₂ ⇔ CH₄+2H₂O, was investigated. The reaction experiments were carried out under the conditions of superficial space velocity 0.08-0.39 1/s, molar ratio of H₂ to CO₂ in the feed gas, 1-5, the amount of the catalyst per unit cross-sectional area of the reactor 0.2-4.3 g/cm², operating pressure 0.2MPa absolute, and temperature 480-720K. The conversion rate was increased about 18% in maximum with the membrane.

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A simulation model was developed to estimate the gas and water balance in a crop production module in a controlled ecological life support system (CELSS). Crops selected were rice, wheat, potato, soybean, peanut, lettuce, and spinach, based on the nutritional requirements of an adult male crew. Plant growth models for these seven crops were described in the literature, modified for use in controlled environments, and incorporated in the simulation model. The models calculate daily photosynthesis, respiration, transpiration, and weights of the leaf, stem, root, and storage organs.
Daily CO₂uptake by plants was estimated using two different transplant date schedules when seven crops were grown together in the module. The result showed that transplant date adjustment was not considered effective in reducing the fluctuations of CO₂ uptake and transpiration. The time course of daily CO₂ uptake and transpiration was estimated using five different growing area divisions for the selected crops. The fluctuations of CO₂ uptake and transpiration decreased with an increase in the number of different growing areas used. The coefficients of variance of daily CO₂ uptake and transpiration in the four different growing areas were approximately 50% of those in the two areas.
Stable gas and water balance in a crop production module is preferable from the viewpoint of a controlled recirculation in a CELSS. This study shows the possibility to apply growth models to simulate gas and water balances in a crop production module in a CELSS and demonstrates that using different growing area divisions with frequent harvests is apparently effective in reducing fluctuations of CO₂ uptake and transpiration.

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Photoautotrophic growth of Euglena gracilis Z was enhanced extremely under 5-40% CO₂ conditions, compared with bubbling air. Euglena cells could not proliferate at more than 50% CO₂ concentration.
In 5-40% CO₂ atomosphere, RuBisCO and chlorophyll contents increased considerably in the cells. The Km value for CO₂ increased in high CO₂ conditions, indicating lowering of the affinity for CO₂. Furthermore Vmax value for CO₂ fixation increased in proportion to the content of chlorophyll.
These results indicate that Euglena gracilis has an ability to adapt and proliferate due to the induction of RuBisCO and chlorophyll biosynthesis into high CO₂ atomosphere.

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The coupling of plant growth and waste recling systems is an important step toward the development of Controlled Ecological Life Support Systems. This study examined suitability of waste wet-oxidized solution for use as a plant nutrient solution.
In order to investigate whether plant could be grown with waste wet-oxidized solution, simulated and modified (P and Fe-enriched) wet-oxidized solution of rabbit feces were prepared with reagents. Lettuce, welsh onion, pea and spinach could not be grown with these solutions.
In order to define what factors in those solutions inhibit growth of plants, lettuces were cultured with standard solution, simulated solution and 7 kinds of modified solutions. As results from the experiment, it, was clarified that shortcomings of wet-oxidized solution as culture solution were excess of Ni cocentration and P, Fe and N deficiencies.
Concentration of Ni in the waste wet-oxidized solution obtained using an experimental equipment with a Ti-lloy furnace was low enough not to inhibit growth of rice plants.

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