Surface Attached BioReactor (SABR) for Microbial Cell Cultivation

SAMBR is a hybrid technology, coupling conventional biological carbon and nitrogen removal and ultrafiltration tubular membranes, capable of nitrogen conversion and removal for water purification and resource recovery. Adapted from a conventional Modified Ludzak-Etinger (MLE) design, Ammonia Oxidizing Bacteria (AOB) nitrify ammonium into nitrate under oxic conditions. An anoxic zone, containing Nitrifying Oxidizing Bacteria (NOB), denitrify the nitrate into diatomic nitrogen that then off-gasses into the atmosphere. By adjusting the active oxic and anoxic zones a blend of nitrogen conversion and removal can be tailored to suit the mission objectives. The treated wastewater is then subjected to membrane filtration to provide a barrier of pathogens and retain active biomass. The membrane permeate produced is a high-quality, particulate free effluent that is rich in nutrients for fertigation (irrigation + fertilizer) applications or can be easily treated downstream to produce drinking water.

The miniature bioreactor system was developed to provide the capabilities for NASA to perform cell studies in space and then provide results back to investigators on Earth with minimal tools and cost. The miniature bioreactor system has the potential to also be used on Earth as a laboratory bench-top cell culturing system without the need for expensive equipment and reagents. The system can be operated under computer control to reduce the operator handling and to reduce result variations. The system includes a bioreactor, a fluid-handling subsystem, a chamber wherein the bioreactor is maintained in a controlled atmosphere and temperature, and control subsystems. The system can be used to culture both anchorage dependent and suspension cells (prokaryotic or eukaryotic cell types). Cells can be cultured for extended periods of time in this system, and samples of cells can be extracted and analyzed at specified intervals. The miniature bioreactor system for cell culturing has applications in pharmaceutical drug screening and cell culture studies.

The Passive Porous Tube Nutrient Delivery System is a plant growth technique that delivers a nutrient solution to the roots of plants via capillary action. The system was designed for use in microgravity. This new system utilizes a ceramic porous tube and water/nutrients bags connected in a loop. No electricity or moving parts are required. Instead, the nutrients are pumped in through a combination of capillary force and evapotranspiration from the plant. The porous tube supplies the plants with the water and nutrients needed to germinate and grow. This system provides an autonomous plant growth apparatus that is simple to assemble, plant and harvest, minimizing the amount of intervention needed in micro-gravity.

PONDS was developed as a water/nutrient delivery system for the Vegetable Production System, called VEGGIE, on the International Space Station (ISS). PONDS uses an innovative wicking material to passively link a water/nutrient reservoir to a plant cylinder. The system enables higher germination rates and improved growth conditions compared to the VEGGIE water/nutrient delivery system currently used on the ISS. PONDs consists of two primary components: a water/nutrient reservoir (Figure 1), and a detachable plant cylinder containing growth substrate and wicking material (Figure 2). The reservoir includes a viewing window that allows the user to observe and record water-use data. The plant cylinder, which screws into the reservoir system, is made from commercial-off-the-shelf materials and fittings. Both the reservoir and plant cylinder include oxygen-permeable windows to enhance aeration to the root zone. Water is delivered from the reservoir to the substrate contained within the plant cylinder via the wicking material inserted into the growth substrate. The wicking material is intrinsically hydrophilic, providing improved capacity compared to the system previously used with VEGGIE. As a result, PONDS can continuously supply water to the root zone within the plant cylinder on demand.

Because resupply of commodities for long duration space missions would be prohibitively expensive and could take an extensive length of time to reach habitats in orbit around or on other planetary bodies, it is critical that astronauts have the ability to recycle and reuse local waste streams to provide resources such as clean water, fuel, and nutrients for growing plants. Scientists at Kennedy Space Center and the University of South Florida have developed a technology that addresses this critical mission need. The modular system design incorporates all wastewater streams and some food waste including urine water, hygiene water, humidity condensate, Sabatier water, fecal waste, laundry water, and organic food waste. These sources are fed simultaneously into the system, and a function-driven, sequential purification process occurs. The primary processes include carbon conversion, phase separation (solid/liquid/gas), disinfection, nutrient/salts management, and salts balancing to generate a clean water stream. The heart of the closed-loop bio-regenerative system is an anaerobic membrane bioreactor (AnMBR), which takes raw wastewater streams and utilizes an anaerobic microbial consortium to carry out the breakdown of the organic matter. An ultrafiltration membrane captures and destroys pathogenic bacteria and viruses. The AnMBR system generates a clean water stream containing fertilizer constituents which can be used to cultivate either microalgae (for food, pharma/nutraceuticals, fuel or bioplastics) in photobioreactors or crops in hydroponic systems. The system also generates methane and hydrogen gas which can be used for fuel (or conversion to bioplastics), and CO2 which can be used to support plant growth.