title: Biodegradation pathway of an anionic surfactant (Igepon TC-42) during recycling waste water through plant hydroponics for advanced life support during long-duration space missions.
abstract: The degradation of an anionic surfactant (Igepon TC-42) was investigated as part of an integrated study of direct recycling of human hygiene water through hydroponic plant growth systems. Several chemical approaches were developed to characterize the degradation of Igepon and to measure the accumulation of intermediates such as fatty acids and methyl taurine. Igepon was rapidly degraded as indicated by the reduction of methylene blue active substances (MBAS) and component fatty acids. The Igepon degradation rate continued to increase over a period of several weeks following repeated daily exposure to 18 micrograms/l Igepon. The accumulation of free fatty acids and methyl taurine was also observed during decomposition of Igepon. The concentration of methyl taurine was below detection limit (0.2 nmol/ml) during the slow phase of Igepon degradation, and increased to 1-2 nmol/ml during the phase of rapid degradation. These findings support a degradation pathway involving initial hydrolysis of amide to release fatty acids and methyl taurine, and subsequent degradation of these intermediates.
authors.affiliation: Dynamac Corp., Kennedy Space Center (KSC), USA.
authors.forename: L H
authors.initials: LH
authors.lastname: Levine
authors.forename: H R
authors.initials: HR
authors.lastname: Kagie
authors.forename: J L
authors.initials: JL
authors.lastname: Garland
mesh_terms: D001673:Biodegradation, Environmental; D003470:Culture Media / Q000032:analysis; D018504:Ecological Systems, Closed; D005227:Fatty Acids / Q000032:analysis; D006801:Humans; D018527:Hydroponics; D008021:Life Support Systems; D008751:Methylene Blue / Q000032:analysis; D013025:Glycine max; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism*; D013654:Taurine / Q000031:analogs & derivatives*; D014908:Triticum; D014865:Waste Disposal, Fluid; D018505:Waste Management / Q000379:methods; D014871:Water Microbiology
chemical_list: D003470:Culture Media; D005227:Fatty Acids; D013501:Surface-Active Agents; D013654:Taurine; D008751:Methylene Blue