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Significance of Plant Root Microorganisms in Reclaiming Water in CELSSSince many microorganisms demonstrate the ability to quickly break down complex mixtures of waste and environmental contaminants, examining their potential use for water recycling in a closed environment is appealing. Water contributes approximately 90 percent of the life sustaining provisions in a human space habitat. Nearly half of the daily water requirements will be used for personal hygiene and dish washing. The primary contaminants of the used "gray" water will be the cleansing agents or soaps used to carry out these functions. Reclaiming water from the gray water waste streams is one goal of the NASA program, Controlled Ecological Life Support Systems (CELSS). The microorganisms of plane roots are well documented to be of a beneficial effect to promote plant growth. Most plants exhibit a range of bacteria and fungi which can be highly plant-specific. In our investigations with lettuce grown in hydroponic culture, we identified a microflora of normal rhizosphere. When the roots were exposed to an anionic surfactant, the species diversity changed, based on morphological characteristics, with the numbers of species being reduced from 7 to 2 after 48 hours of exposure. In addition, the species that became dominant in the presence of the anionic surfactant also demonstrated a dramatic increase in population density which corresponded to the degradation of the surfactant in the root zone. The potential for using these or other rhizosphere bacteria as a primary or secondary waste processor is promising, but a number of issues still warrant investigation; these include but are not limited to: (1) the full identification of the microbes, (2) the classes of surfactants the microbes will degrade, (3) the environmental conditions required for optimal processing efficiency and (4) the ability of transferring the microbes to a non-living solid matrix such as a bioreactor.
Document ID
20020039641
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Bubenheim, David L.
(NASA Ames Research Center Moffett Field, CA United States)
Greene, Catherine
(Lockheed Martin Engineering and Sciences Co. United States)
Wignarajah, Kanapathipillai
(Lockheed Martin Engineering and Sciences Co. United States)
Kliss, Mark H.
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Life Sciences (General)
Meeting Information
Meeting: 31st COSPAR Scientific Assembly
Location: Birmingham
Country: United Kingdom
Start Date: July 14, 1996
End Date: July 21, 1996
Sponsors: Committee on Space Research
Funding Number(s)
PROJECT: RTOP 199-61-62
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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