Search Results

A material recycling or circulating system is an essential component of a Controlled Ecological Life Support System (CELSS) in a closed space such as in space, on the moon or in the deep sea. The system is divided into two types: one is a biosystem and other one is a non-biosystem or pure chemical-type. Both have advantages and disadvantages, respectively. In a previous report, we have reported a microalgal culturing system for CO2 elimination and O2 regeneration or a so-called life support sytem, in closed air on the ground by using the photosynthetic alga, Euglena gracilis. z. The present study was initiated to establish an optimal design for a microorganism-reactor for a material circulating system, especially for feces, garbage and sewage in a CELSS. We focused on the microorganisms in the present culturing system. We investigated to find the best microorganisms for a material circulation system that functions effectively in the CELSS.

We have reported that Euglena, a photosynthetic alga, has the ability to grow in a high CO2 atmosphere and yield great biomass due to the induction of chlorophyll biosynthesis under high CO2 conditions. In the present study, we investigated some microalgal culturing systems for CO2 elimination and O2 regeneration in closed air on the ground by using the photosynthetic alga, Euglena gracilis. z. In the first part of our experiments, we focused on the effects of CO2 and light intensity in the present culture system. We investigated to determine the optimum culture conditions for a microalgal culture system that functions effectively in the controlled ecological life support systems (CELSS). We determined the maximum elimination rate under a high concentration of CO2 with stirring of the supply gas by bubbling. We found that the maximum CO2 elimination rate or gas exchange performance under a 10 % concentration of CO2 was about 2.3 times higher than its low concentration of CO2 (0.04 %).