|ognizant Communication Corporation|
LIFE SUPPORT & BIOSPHERE SCIENCE
VOLUME 7, NUMBER 3, 2000
Life Support & Biosphere Science, Vol. 7, pp. 225-232, 2000
1069-9422/00 $20.00 + .00
Copyright © 2000 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.
Guntur V. Subbarao,1 Raymond M. Wheeler,2 and Gary W. Stutte3
1US National Research Council, 2NASA Biomedical Office, and 3Dynamac Corporation, Kennedy Space Center, FL 32899
Recycling of nutrients, air, and water is an integral feature of life support systems designed for long-term space missions. Plants can play a major role in supplying the basic life support requirements, which include providing the crew's food, clean water, and air, and recycling their wastes. The nutrient flux through the plant and human systems needs to be matched in order for nutrients to recycle between humans and plants without an excessive buildup in any one section of the system. Sodium, which is essential at the macronutrient level for human metabolism, has only been shown to be a micronutrient for some plants, with only very limited uptake in most plants. Thus, when Na is added from the outside to meet the human demand in these closed life support systems it will accumulate someplace in the overall system. In simple systems such as these, without a complete biogeological cycle, the buildup of Na could occur in the nutrient solution of the plant system. Various concepts related to the substitution of sodium for potassium in crop plants are currently being investigated by NASA. Results to date suggest that Na concentrations up to 100 g kg-1 dry weight may be achievable in the edible portions of Na-tolerant crops (e.g., red beet and chard). A flow path for nutrient solution high in Na wastes has been suggested for optimizing Na and nitrogen incorporation and utilization from such solutions. Options for further improvements include selecting plant genotypes tolerant to high salinity, which are efficient in Na uptake. This should also be combined with environmental manipulations to maximize Na uptake by crop plants.
Key words: Potassium; Sodium; Substitution; Sodium management; Nutrient recycling; Advanced life support
Address correspondence to Raymond M. Wheeler. Fax: (321) 853-4165; E-mail: email@example.com
Cheryl J. Greenwalt1* and Jean Hunter2
1Department of Food Science and 2Department of Agricultural and Biological Engineering, Cornell University, Ithaca, NY 14853
Edible oil is a critical component of the proposed plant-based Advanced Life Support (ALS) diet. Soybean, peanut, and single-cell oil are the oil source options to date. In terrestrial manufacture, oil is ordinarily extracted with hexane, an organic solvent. However, exposed solvents are not permitted in the spacecraft environment or in enclosed human tests by National Aeronautics and Space Administration due to their potential danger and handling difficulty. As a result, alternative oil-processing methods will need to be utilized. Preparation and recovery options include traditional dehulling, crushing, conditioning, and flaking, extrusion, pressing, water extraction, and supercritical extraction. These processing options were evaluated on criteria appropriate to the Advanced Life Support System and BIO-Plex application including: product quality, product stability, waste production, risk, energy needs, labor requirements, utilization of nonrenewable resources, usefulness of by-products, and versatility and mass of equipment to determine the most appropriate ALS edible oil-processing operation.
Key words: Advanced life support; BIO-Plex; Edible oil; Oil processing
Address correspondence to Jean Hunter. Tel: (607) 255-2297; Fax: (607) 255-4080; E-mail: firstname.lastname@example.org
*Current address: Kraft Foods, Inc., 801 Waukegan Road, Glenview, IL 60025.
Ozonation and Alkaline-Peroxide Pretreatment of Wheat Straw for Cryptococcus Curvatus Fermentation
Cheryl J. Greenwalt,1* Jean B. Hunter,2 Shuwei Lin,2 Scott Mckenzie,3 and Adrian Denvir3
1Department of Food Science and 2Department of
Agricultural and Biological Engineering, Cornell University, Ithaca, NY
3Lynntech, Inc., 7610 Eastmark Drive, Suite 105, College Station, TX 77840
Crop residues in an Advanced Life Support System (ALS) contain many valuable components that could be recovered and used. Wheat is 60% inedible, with approximately 90% of the total sugars in the residue cellulose and hemicellulose. To release these sugars requires pretreatment followed by enzymatic hydrolysis. Cryptococcus curvatus, an oleaginous yeast, uses the sugars in cellulose and hemicellulose for growth and production of storage triglycerides. In this investigation, alkaline-peroxide and ozonation pretreatment methods were compared for their efficiency to release glucose and xylose to be used in the cultivation of C. curvatus. Leaching the biomass with water at 65°C for 4 h prior to pretreatment facilitated saccharification. Alkaline-peroxide and ozone pretreatment were almost 100% and 80% saccharification efficient, respectively. The sugars derived from the hydrolysis of alkaline-peroxide-treated wheat straw supported the growth of C. curvatus and the production of edible single-cell oil.
Key words: Advanced life support; Biomass conversion; Pretreatment; Saccharification; Crop residue; Wheat biomass
Address correspondence to Jean B. Hunter. Tel: (607) 255-2297; Fax: (607) 255-4080; E-mail: email@example.com
*Current address: Kraft Foods, Inc., 801 Waukegan Road, Glenview, IL 60025.
Sangho Lee and Richard M. Lueptow
Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208
Essential to extended human exploration and utilization of space is providing a clean supply of potable water as well as water for washing. Recycling of space mission wastewater is necessary for long-term space missions due to the limited capacity of water storage. In this study, initial measurements toward a wastewater reclamation system that provides a clean water supply using reverse osmosis (RO) membranes have been made using stirred cell filtration experiments. Low-pressure reverse osmosis (LPRO) membranes were used to obtain high flux of permeate as well as high rejection. Detergent removal was above 99%, and dissolved salt removal was above 90% in single-pass treatment, while total organic carbon (TOC) removal was nearly 80%. Most problematic is nitrogen rejection, which was 74% at best. Comparison of feed water before and after urea hydrolysis shows that the rejection of nitrogen compounds can be increased to 95% by allowing urea hydrolysis to occur. The removal efficiency for nitrogen compounds was also improved by increasing the shear rate near membrane surface. As a result, the product water in two passes could meet the hygiene water requirements for human space missions, and the product water in three passes could meet potable water regulations with overall recovery of 77%. This study also suggests that dynamic rotating membrane filtration, which can produce a high shear rate, will be useful to increase the system recovery as well as pollutant rejection.
Key words: Wastewater reclamation; Drinking water; Physicochemical treatment; Membrane; Reverse osmosis
Address correspondence to Richard M. Lueptow. Tel: (847) 491-4265; Fax: (847) 491-3915; E-mail firstname.lastname@example.org
Silica Deposition on the Leaves of Mir- and Earth-Grown Super Dwarf Wheat
William F. Campbell,1 David L. Bubenheim,2 Frank B. Salisbury,1 Gail E. Bingham,1 William R. Mcmanus,3 H. D. Biesinger,1 D. T. Strickland,1 Margarita Levinskikh,4 Vladimir N. Sytchev,4 Igor Podolsky,4 Irene Ivanova,4 Lola Chernova,4 And Gary Jahns2
1Department Plants, Soils, and Biometeorology, Utah State
University, Logan, UT 84322-4820
2NASA/Ames, Moffett Field, CA 94035
3Biology Department, Utah State University, Logan, UT 84322-5305
4Institute of BioMedical Problems, Moscow, Russia
Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis were used to investigate the nature of crystals deposited on leaves of Mir- and Earth-grown Super Dwarf wheat (Triticum aestivum L.) plants. Leaves from these plants exhibited dense and uniformly distributed crystals on leaf abaxial surfaces when viewed by SEM. Young leaves showed that crystals initially accumulated around the stomata on the adaxial surface, but became more dense and uniformly distributed as the leaves aged. EDX microanalyses of the Balkanine (a nutrient charged clinoptilolite zeolite) medium in which the wheat plants were grown showed an elemental pattern similar to that observed on the wheat leaves. The absence of N and P in the Balkanine suggests that they were completely utilized by the plants. Only Si and O were evident in the drying agent, Sorb-it-SilicaT, and perhaps could have accounted for some of the Si observed on the plant tissue.
Key words: Triticum aestivum; Microgravity; Scanning electron microscopy; Energy-dispersive X-ray analysis; Balkanine; Sorb-it-SilicaT; Mir; Super Dwarf wheat
Address correspondence to William F. Campbell. Tel: (435) 797-2253; Fax: (435) 797-3376; E-mail: email@example.com
Global Ecotechnics Corporation, 7 Silver Hills Road, Santa Fe, NM 87505
Artificial biospheres of the scale and complexity of Biosphere 2 can only work with coordinated rigorous design at each level of ecology: biospheres, biomes, bioregions, ecosystems, communities, patches, phases, physical-chemical functions, guilds, populations, organisms, and cells (both eucaryotic and procaryotic). This article reviews these theoretical concepts and provides examples of how this structure was applied to the design and development of Biosphere 2. In addition to this ecological engineering design, the addition of humans as inhabitants in the closed system required design of ethnological patterns and of technical and cybernetic systems for meeting specifically human requirements of labor efficiency, climate, nutrition, wastewater recycle, and pure air and water. Ecological levels of biospheric complexity can be directly applied to studies of the Earth's biosphere and, in fact, must be used to understand complex biospheric processes.
Key words: Artificial biospheres; Global ecology; Biosphere 2; Ecological engineering; Ecosystems
Address correspondence to John Allen. Tel: (505) 424-0237; Fax: (505)
424-3336; E-mail: firstname.lastname@example.org