Survey of Microbial Community in Bioreactors Used for Bioregenerative Water Purification

Bioregenerative water purification systems are promising ECLSS technologies because they allow for complete recovery of water and nutrients for sustainable planetary base operations. These systems use a consortium of microbes to treat complex waste streams that have generally been ignored thus far, such as fecal and food waste. However, the microbial community structure of the bioreactors is largely unknown. The main goal of this paper was to survey the microbial community of four distinct bioreactors to provide a deeper understanding of the bioreactors in terms of treatment and operational hazards. The survey encompassed four types of aerobic and anaerobic bioreactors with real and ersatz influents, giving a wide picture of the microbial community across a wide range of conditions. We used shotgun metagenomics to provide a comprehensive analysis of the community constituents, which included bacteria, viruses, archaea, and eucarya. The study sampled two identical anaerobic membrane bioreactors (one with canine fecal waste influent and one with an ersatz influent), a suspended aerobic membrane bioreactor (with real human urine as its influent), and a photo−membrane bioreactor (with anaerobic membrane bioreactor effluent as its influent). This is the first study of its kind to study the microbiome of bioreactors designed for early planetary wastewater treatment. Results show a high level of diversity among the samples, with higher DNA densities in the samples from the reactors with real fecal and urine influents. Overall, this conference paper will detail how the bioreactor conditions affected the microbial community structure and how the community structure influences the wastewater treatment process.