Development and Molecular Characterization of Microbial Inocula for Initiation of Graywater Waste Processing Systems on Long-Term Space Flights

Abstract

Microorganisms will be an integral part of biologically based waste processing systems used for water purification or nutrient recycling on space flights. Establishment of these systems with a defined group of microorganisms will provide a standardized means for conferring specific properties to the system. Phylogenetic analysis of 16S rDNA sequences from a clonal library of organisms from a graywater-degrading rhizosphere community suggested that members of the Cytophagales and Proteobacter phylogenetic groups dominated. A clonal library of organisms from an industrial wastewater treatment plant (WWTP) was more diverse and consisted of organisms from more phylogenetic groups. This analysis provided the basis for selection of organisms for use in a defined, constructed community and for selection of a source of an undefined, complex microbial inoculum. The constructed community and the sludge inoculum were inoculated into a model plant rhizosphere waste processing system to evaluate survival. Based on plant, microbiological and molecular biological measures, it appeared that both inoculated communities were able to become established and persist in this model wastewater processing system.