Arthrospira sp. growth in photobioreactor : model and simulation of the ISS and ground experiments

International audienceThe Arthrospira-B experiment is the first experiment in space ever allowing the online measurements of both oxygen production rate and growth rate of Arthrospira sp. in batch photobioreactors running in ISS. A 4 bioreactors system was integrated in the ISS Biolab incubator. Each reactor is composed of two chambers (gas/liquid) separated by a PTFE membrane and have been running in batch conditions. Oxygen production is measured by online measurement of the pressure increase in the gas chamber. The experiments are composed of several successive batch cultures for each reactor, performed in parallel on ISS and on ground. In this work, a model for the growth of Arthrospira sp in these membrane photobioreactors is proposed and the simulations results obtained are compared to the experimental results gathered in microgravity and on ground. The photobioreactor model is based on a light transfer limitation model, already used to describe and predict the growth and oxygen production in small to large scale ground photobioreactors. This approach is completed by a model for pH in the liquid phase. This permits to consider the pH increase associated to the bicarbonate consumption for the biomass growth. A membrane gas-liquid transfer model is used to predict the gas pressure increase in the gas chamber. Substrate limitation, pH inhibition, as well as oxygen inhibition must be considered in the biological model. A good fitting is achieved between experimental and simulation results when a good mixing of the liquid phase is maintained. These data show that microgravity has no first order effect on Arthrospira growth rate in a photobioreactor operating in space in ISS

Oxygen Regeneration by Algae Cultivation in Photo-Bioreactor for ISS Cabin Technology Demonstrator

International audienceOxygen regeneration from ambient carbon dioxide is a fundamental technology building block for future life support systems for space applications. BIORAT1 Phase B2 project consists in the development of the Preliminary Design Review (PDR) level design of an On Board Demonstrator (OBD) to be hosted in European Drawer Rack 2(EDR2) facility on board of the ISS. The core of the OBD is a Photo-Bioreactor (PBR) filled with spirulina (Limnospira indica PCC 8005) producing oxygen from carbon dioxide and light by photosynthesis. A Liquid Loop (LL) transports the oxygen & carbon dioxide dissolved into the cultivation medium liquid between the Photobioreactor (PBR) and the ISS cabin ambient air. The Gas Exchange Module (GEM) enables the exchange of Oxygen & Carbon Dioxyde separates the cultivation medium liquid to the ambient air while keeping the liquid inside the LL. The design of this flight hardware is supported by tests results obtained with a Bread Board Model (BBM). In this paper, we present the results of the long duration spirulina cultivation test performed with the BBM. allowing verification of the long term functionality of the PBR & LL including the GEM. The PBR performances together with correlation to the model of the cultivated algae growth and oxygen production are presented. Future development and expected results and perspectives are also presented and discussed

Greenhouse Module for Space System: A Lunar Greenhouse Design

In the next 10 to 20 years humankind will return to the Moon and/or travel to Mars. It is likely that astronauts will eventually build permanent settlements there, as a base for long-term crew tended research tasks. It is obvious that the crew of such settlements will need food to survive. With current mission architectures the provision of food for longduration missions away from Earth requires a significant number of resupply flights. Furthermore, it would be infeasible to provide the crew with continuous access to fresh produce, specifically crops with high water content such as tomatoes and peppers, on account of their limited shelf life. A greenhouse as an integrated part of a planetary surface base would be one solution to solve this challenge for long-duration missions. Astronauts could grow their own fresh fruit and vegetables in-situ to be more independent from supply from Earth. This paper presents the results of the design project for such a greenhouse, which was carried out by DLR and its partners within the framework of the Micro-Ecological Life Support System Alternative (MELiSSA) program. The consortium performed an extensive system analysis followed by a definition of system and subsystem requirements for greenhouse modules. Over 270 requirements were defined in this process. Afterwards the consortium performed an in-depth analysis of illumination strategies, potential growth accommodations and shapes for the external structure. Five different options for the outer shape were investigated, each of them with a set of possible internal configurations. Using the Analytical Hierarchy Process, the different concept options were evaluated and ranked against each other. The design option with the highest ranking was an inflatable outer structure with a rigid inner core, in which the subsystems are mounted. The inflatable shell is wrapped around the core during launch and transit to the lunar surface. The paper provides an overview of the final design, which was further detailed in a concurrent engineering design study. During the study, the subsystem parameters (e.g. mass, power, performance) were calculated and evaluated. The results of the study were further elaborated, leading to a lunar greenhouse concept that fulfils all initial requirements. The greenhouse module has a total cultivation area of more than 650 m² and provides more than 4100 kg of edible dry mass over the duration of the mission. Based on the study, the consortium also identified technology and knowledge gaps (not part of this paper), which have to be addressed in future projects to make the actual development of such a lunar greenhouse, and permanent settlements for long-term human-tended research tasks on other terrestrial bodies, feasible in the first place

Recycling nutrients from organic waste for growing higher plants in the Micro Ecological Life Support System Alternative (MELiSSA) loop during long-term space missions

Space agencies are developing Bioregenerative Life Support Systems (BLSS) in view of upcoming long-term crewed space missions. Most of these BLSS plan to include various crops to produce different types of foods, clean water, and O2 while capturing CO2 from the atmosphere. However, growing these plants will require the appropriate addition of nutrients in forms that are available. As shipping fertilizers from Earth would be too costly, it will be necessary to use waste-derived nutrients. Using the example of the MELiSSA (Micro-Ecological Life Support System Alternative) loop of the European Space Agency, this paper reviews what should be considered so that nutrients recycled from waste streams could be used by plants grown in a hydroponic system. Whereas substantial research has been conducted on nitrogen and phosphorus recovery from human urine, much work remains to be done on recovering nutrients from other liquid and solid organic waste. It is essential to continue to study ways to efficiently remove sodium and chloride from urine and other organic waste to prevent the spread of these elements to the rest of the MELiSSA loop. A full nitrogen balance at habitat level will have to be achieved; on one hand, sufficient N2 will be needed to maintain atmospheric pressure at a proper level and on the other, enough mineral nitrogen will have to be provided to the plants to ensure biomass production. From a plant nutrition point of view, we will need to evaluate whether the flux of nutrients reaching the hydroponic system will enable the production of nutrient solutions able to sustain a wide variety of crops. We will also have to assess the nutrient use efficiency of these crops and how that efficiency might be increased. Techniques and sensors will have to be developed to grow the plants, considering low levels or the total absence of gravity, the limited volume available to plant growth systems, variations in plant needs, the recycling of nutrient solutions, and eventually the ultimate disposal of waste that can no longer be used.ISSN:2214-5532ISSN:2214-552

limnospira indica pcc8005 growth in photobioreactor: model and simulation of the iss and ground experiments

limnospira indica pcc8005 growth in photobioreactor2020-11-25International audiencethe arthrospira-b experiment is the first experiment in space ever allowing the online measurements of both oxygen production rate and growth rate of limnospira indica pcc8005 in batch photobioreactors running on-board iss. four bioreactors were integrated in the iss biolab facility. each reactor was composed of two chambers (gas and liquid) separated by a ptfe membrane and was run in batch conditions. oxygen production was monitored by online measurement of the total pressure increase in the gas chamber. the experiments are composed of several successive batch cultures for each reactor, performed in parallel on iss and on ground. in this work, a model for the growth of the cyanobacterium limnospira indica pcc8005 (also known as arthrospira or spirulina) in these space membrane photobioreactors was proposed and the simulation results obtained are compared to the experimental results gathered in space and on ground. the photobioreactor model was based on a light transfer limitation model, already used to describe and predict the growth and oxygen production in small to large scale ground photobioreactors. it was completed by a model for ph prediction in the liquid phase allowing assessment of the ph increase associated to the bicarbonate consumption for the biomass growth. a membrane gas-liquid transfer model is used to predict the gas pressure increase in the gas chamber. substrate limitation is considered in the biological model. a quite satisfactory fit was achieved between experimental and simulation results when a suitable mixing of the liquid phase was maintained. the data showed that microgravity has no first order effect on the oxygen production rate of limnospira indica pcc8005 in a photobioreactor operating in space in zero gravity conditions

BIORAT: Oxygen Recycling between an Algae Photo-bioreactor and a Consumer

International audienc

Reactivation of microbial nitrogen cycling conversions after Lower Earth Orbit Space exposure

Various processes within the microbial nitrogen cycle are considered as resource efficient alternatives to the physicochemical methods for recovery of both nitrogen and water for long-term manned Space missions. One of the major application challenges is to start up biological reactors with inocula that can be preserved under the conditions of microgravity and radiation conditions prevalent in Space. Furthermore, when a biological treatment system fails, re-inoculation should prevent that it take months to recover steady-state operation. In the current study, a Space flight was performed with (i) three natural microbial communities, containing members of the ammonia oxidizing archaea (AOA) and bacteria (AOB), nitrite oxidizing bacteria (NOB), denitrifiers and anammox bacteria (AnAOB), and with (ii) a synthetic culture of the ureolytic Cupriavidus pinatubonensis, the AOB Nitrosomonas europaea and the NOB Nitrobacter winogradskyi. The cultures were sent on a PHOTON-M4 flight to Lower Earth Orbit (LEO) Space and were exposed to 20 ± 4oC, hyper and μ-gravity and to 30.5 ± 6.9 mGy of radiation over 44 days. Upon return to Earth the cultures were reactivated and volumetric activity in mg N L-1 d-1 was compared to the same cultures that were stored terrestrially at ambient temperature (23 ± 3°C) and in the refrigerator (4oC). It should be noted that the measured background radiation on Earth was only 1.6 ± 0.1 mGy over the same period. Nevertheless the LEO-samples performed either similar or better after reactivation compared to the ambient terrestrial stored cultures. Both the LEO and the ambient terrestrial stored cultures showed a significant decline in activity compared 4oC storage. More in-depth data on specific conversion rates, changes in biomass concentrations, cell viability tests using flow cytometry, Illumina-sequencing of the microbial communities is being processed. In conclusion, this study for the first time reports on the specific Space-flight survival capacity of the key conversions in the microbial nitrogen cycle, a necessary step in advancing toward a bio-regenerative life support system

BEAST_crown_1_max_cred

Maximum clade credibility tree from the BEAST analysis in which the MrBayes tree topology was constrained to remain constant and the crown age of Viburnum was fixed to 1 (uniform prior 0.99–1.01)