|ognizant Communication Corporation|
LIFE SUPPORT & BIOSPHERE SCIENCE
VOLUME 8, NUMBER 1
Life Support & Biosphere Science, Vol. 8, pp. 1-7
1069-9422/01 $20.00 + .00
Copyright © 2001 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.
Yael Vodovotz1 and Dawn L. Hentges2
1Department of Food Science & Technology, The Ohio State
University, Columbus, OH 43210
2School of Family and Consumer Sciences, Bowling Green State University, Bowling Green, OH, 43403
Soybeans have been selected to be grown in a habitat (BIO-Plex, Bioregenerative Planetary Life Support Systems Test Complex) designed to evaluate advanced life support systems for long-duration space missions. Soymilk and soy bread will be incorporated into this nutritious, plant-based food system. Because all consumables will be recycled and reused, food safety is a particular concern. Critical control points were identified to control microbiological hazards, particularly mycotoxins, and chemical hazards from antinutrients and volatiles emitted during processing of soymilk and soy bread. Volatile compounds, evolved during the manufacturing of soymilk and soy bread, were quantified by GC/MS to assess their impact on this closed loop system. All concentrations of volatiles evolved during soymilk production were below the 24-h Space Craft Maximum Allowable Concentration (SMAC), while acetaldehyde surpassed the SMAC criteria for soy bread. Recommendations were made for processing of soybeans in such environments to minimize risk to crew member health.
Key words: Soybeans; Food safety; Volatiles; Advanced life support; Space food
Address correspondence to Yael Vodovotz, Department of Food Science & Technology, 110 Parker Food Science and Technology Bldg., 2015 Fyffe Court, The Ohio State University, Columbus, OH 43210. Tel: (614) 247-7696; Fax: (614) 292-0218; E-mail: firstname.lastname@example.org
Selecting a Sensitive Bacteriophage Assay for Evaluation of a Prototype Water Recycling System
Gail Montgomery Brion1 and Joann Silverstein2
1Department of Civil Engineering, University of Kentucky,
161 Raymond Bldg., Lexington, KY 40506-0281
2Department of Civil, Environmental, and Architectural Engineering, University of Colorado at Boulder, Campus Box 428, Boulder, CO 80309-0428
A rapid, simple, and direct (RSD) assay of eluate from filter concentration was developed to enumerate low numbers of MS2 bacteriophage, used as a surrogate for enteric viruses, from samples collected from a prototype-sized water recycling system. The RSD assay utilized a 50-ml eluate volume in a modified single-layer assay, neutralizing eluate pH by buffered, double-strength agar. The RSD assay developed was simpler and minimized sample-handling steps compared with another published method. The RSD assay method showed greater sensitivity than the other published method for recovering phage from filter eluate while avoiding pH shifts, which can inactivate phage.
Key words: Phage assay; MS2; Monitoring; Water recycling; Iodine
Address correspondence to Gail M. Brion, Department of Civil Engineering, University of Kentucky, 161 Raymond Bldg., Lexington, KY 40506-0281. Tel: (859) 257-4467; Fax: (859) 257-4404; E-mail: email@example.com
Development and Characterization of Edible Peanut Protein Films
Nefertiti Patrick, Yong X. Gan, and Heshmat A. Aglan
Mechanical Engineering Department, Tuskegee University, Tuskegee, AL 36088
In this work, novel edible films were developed from peanut protein with sorbitol as a plasticizer. The peanut protein was extracted from peanut flour. Two groups of films were prepared. One group contained 10% in weight of natural oil/fat of the peanuts, while the other group contained no oil/fat. Six types of films with 37.5%, 44.5%, and 50% sorbitol content by weight, with and without fat, were chosen for mechanical properties characterization and microscopic observations. It was found that with the increase of sorbitol content, higher tensile strength and higher Young's modulus were achieved for the films without fat. However, films with fat exhibited maximum strength and modulus at 44.5% sorbitol content. Relationships between the mechanical properties and the microscopic features of these films were established. It was found that the higher the content of the sorbitol, the more evident the crystalline structure.
Key words: Edible films; Peanut protein; Sorbitol; Mechanical properties; Microscopic features
Address correspondence to Heshmat A. Aglan, Mechanical Engineering Department, Tuskegee University, Tuskegee, AL 36088. Tel: (334) 727-8973; Fax: (334) 727-8090; E-mail: firstname.lastname@example.org
Electrochemical Removal of Ammonium Ions from a Bioreactor Effluent
Jinseong Kim, Anuncia Gonzalez-Martin, Carlos Salinas, and Larris Andrew Rutherford
Lynntech, Inc., 7610 Eastmark Dr., Suite 202, College Station, TX 77840
Ammonium ions are byproducts of the oxidation of nitrogen-containing substances occurring in the initial treatment steps of water recovery systems. Removal of ammonium ions from the effluent stream from 1000 ppm to less than 0.25 ppm is an imperative need as a part of the space life support infrastructure. Drawbacks associated with processes proposed in the past include the generation of a secondary waste, cost, size, and/or the use of consumables that need to be stored or supplied. Lynntech has developed a technology that is based on an innovative, environmentally friendly electrochemical process for the effective removal of ammonium ions. The process does not use consumables except for oxygen gas from air, and does not generate a secondary waste. By controlling operational conditions, the ammonium ions may be transformed to nitrogen gas and/or to nitrate ions. Other advantages of the process include: it is energy efficient, operates at room temperature, and is microgravity compatible.
Key words: Ammonium oxidation; Bioreactor; Electrochemical reactor; Bioreactor effluent
Address correspondence to Jinseong Kim, Lynntech, Inc., 7610 Eastmark Dr., Suite 202, College Station, TX 77840. Tel: (979) 693-0017; Fax: (979) 764-7479; E-mail: email@example.com
Anuncia Gonzalez-Martin, Jinseong Kim, John Van Hyfte, Larris A. Rutherford, and Craig Andrews
Lynntech, Inc., 7610 Eastmark Dr., Suite 202, College Station, TX 77840
In spacecraft water recovery systems there is a need to develop a postprocessor water polishing system to remove organic impurities to levels below 250 mg/L (ppb) with a minimum use of expendables. This article addresses the development of a photocatalytic process as a postprocessor water polishing system that is microgravity compatible, operates at room temperature, and requires only a minimal use of both oxygen gas (or air) and electrical power for low energy UV-A (315-400 nm) lamps. In the photocatalytic process, organic contaminants are degraded to benign end products on semiconductor surfaces, usually TiO2. Some challenging issues related to the use of TiO2 for the degradation of organic contaminants have been addressed. These include: i) efficient and stable catalytic material; ii) immobilization of the catalyst to produce a high surface area material that can be used in packed-bed reactors, iii) effective light penetration, iv) effective, microgravity-compatible, oxidant delivery; v) reduced pressure drop, and vi) minimum retention time. The research and development performed on this pholocatalytic process is presented in detail.
Key words: Titanium dioxide; Photoreactor; Water polishing system; Organic oxidation; Packed-bed reactors
Address correspondence to A. Gonzalez-Martin, Lynntech, Inc., 7610 Eastmark Dr., Suite 202, College Station, TX 77840. Tel: (979) 693-0017; Fax: (979) 764-7479.
David H. Fleisher1 and Haim Baruh2
1Department of Plant Biology and Pathology, Rutgers, the
State University of New Jersey, 20 Ag Extension Way, New Brunswick, NJ
2Department of Mechanical and Aerospace Engineering, Rutgers, the State University of New Jersey, 98 Brett Road, Piscataway, NJ 08854-8058
A feedback control method for regulating crop growth in advanced life support systems is presented. Two models for crop growth are considered, one developed by the agricultural industry and used by the Ames Research Center, and a mechanistic model, termed the Energy Cascade model. Proportional and pointwise-optimal control laws are applied to both models using wheat as the crop and light intensity as the control input. The control is particularly sensitive to errors in measurement of crop dry mass. However, it is shown that the proposed approach is a potentially viable way of controlling crop growth as it compensates for model errors and problems associated with applying the desired control input due to environmental disturbances.
Key words: Biomass production; Mathematical modeling; Advanced life support; Feedback control; Model-based control
Address correspondence to David H. Fleisher, Bioresource Engineering, Rutgers, the State University of New Jersey, 20 Ag Extension Way, New Brunswick, NJ 08901-8500. Tel: (732) 932-9753; Fax: (732) 932-7931; E-mail: firstname.lastname@example.org
Development of a Microgravity-Compatible Reagentless Organic Acid and Alcohol Monitor (Oaam)
James R. Akse, James E. Atwater, and John T. Holtsnider
UMPQUA Research Company, P.O. Box 609, Myrtle Creek, OR 97457
The development of a microgravity-compatible analyzer capable of quantifying organic acids in water is described. The analyzer employs "reagentless" solid phase acidification to convert organic acids to the volatile form followed by membrane separation and specific conductance detection to determine organic acids at concentrations between 0.005 and 40 mg/L. In the future, this technology will be extended to the detection of alcohols, which will be oxidized to form the corresponding organic acid and then determined using the same processes. An immobilized enzyme biocatalyst, alcohol oxidase, oxidizes alcohols to form an aldehyde. Oxidation to the corresponding organic acid is then completed over a heterogeneous catalyst. The combined organic acid and alcohol monitor (OAAM) will be utilized to determine levels of both analyte classes at various points within the water recovery system (WRS) baselined for the International Space Station (ISS). These data will improve water quality through enhanced process control, while allowing early diagnosis of potential problems.
Key words: Organic acids; Analysis; Alcohols; Water recovery system
Address correspondence to James R. Akse, Ph.D., UMPQUA Research Company,
P.O. Box 609, Myrtle Creek, OR 97457. Tel: (541) 863-2653; Fax: (541) 863-7770;