Characterization of microbial consortia adapted to degrade space organic waste

Selection and characterization of bacterial communities capable of carrying out an efficient degradation of simulated organic waste (SOW) produced during space missions. The microbiome naturally occurring in the space organic wastes was enriched through sequential batch cultivation under anaerobic conditions. The characteristics and evolution of the composition of two bacterial consortia corresponding to the second (S2-2) and fifth (S5-3) enrichment passage were studied by metagenomics sequencing the 16S rRNA gene.Both bacterial consortia brought about a statistically significant reduction of organic biomass in comparison to the organic waste fermented without adding bacterial consortia as inocula. Total extractives were the main components consumed and on average 40% of cellulose was degraded during the fermentation process when the two bacterial consortia were applied. Metagenomic results revealed the absence of Archaea in both bacterial consortia. The enrichment process led to the selection in the two consortia of bacterial communities genetically different with similar metabolic functions with an increase of the relative abundance of facultative/obligate genera.