Eu:CROPIS – Euglena and Combined Regenerative Organic-food Production in Space

Abstract

The Eu:CROPIS mission within the DLR compact satellite program offers for the first time the opportunity of analyzing coupled biological life support systems under different accelerations (moon and mars) utilizing state of the art methods for image and molecular analysis in a long term experiment. A major problem in manned space flight is the processing of urine. Water is the only component in urine that is recovered, yet. All dissolved substances such as urea and salts are extracted from the urine and then discarded. There was never an attempt to use these valuable commodities and include them in a closed system. The urine of habitat residents can be used to grow fresh fruits and vegetables after proper conversion. Eu:CROPIS shall prove this concept under varying conditions of gravity. Within the compact satellite Eu:CROPIS two life support systems will be combined for producing biomass out of urine. The used biological systems are: a nitrifying trickle filter system (C.R.O.P.) for using the urine as nitrogen source and Euglena gracilis as oxygen producing element. Also Euglena can protect the whole system against high level of ammonia which can occur during a low nitrification process. Euglena gracilis is a motile photosynthetic unicellular flagellate living in ponds and lakes. It uses gravity and light as hints to reach and stay in regions of the water column optimal for photosynthesis and growth. Euglena is considered a ‘professional gravi-sensing organism’, a term that was coined by ESA. In the past 15 years, Euglena has been established as a model organism for studying gravity perception of single cells. The core element of the C.R.O.P. system is a microbiological trickle filter made of lava rock. The lava rock is used as a habitat for a variety of microorganisms such as bacteria, fungi and protozoa. The high degree of adaptability of this system with respect to organismic diversity allows the use for the degradation and detoxification of various substances passing through the filter tube. The filter is able to adjust dynamically to the fed substances by selective reproduction of the organisms that can degrade and utilize these substances as their food base. As higher plant system small tomatoes (Micro-Tina) will be used for biomass production. Scientific aim is a seed to seed experiment under the gravitational conditions like on moon (0.16g) and on mars (0.38g) each for 6 months. During the long term experiment ion concentrations in the water based flow will be measured by ion chromatography and molecular biological analysis will be performed with euglena cells. The Eu:CROPIS long term experiment will serve the purpose of feasibility and technology demonstration in the field of combined biological life support systems and gravitational biological research on a compact satellite system.