Development of a Urine Recycling Chemostat System Coupled to an Ammonia Fuel Cell Using Urease-Positive P. vulgaris Bacteria for Urea Removal

Abstract

Current urine recycling treatments are unable to completely recover clean water free of toxic metabolic products such as urea. Urea is a small and uncharged molecule, diffulting its removal from wastewater. Previous publications from our research group reported the use of immobilized urease enzyme on carbon matrix as a urea bioreactor to convert urea to ammonia. The stability of the enzyme was limitation for long time use. For this, a microbial system has been selected. An ureolysis system in a microbial chemostat using robust Proteus vulgaris bacteria that can transform urea to ammonia is being proposed. The chemostat will be coupled to an ammonia fuel cell to further oxidize ammonia to nitrogen and generate energy. The first goal of this work is to establish the growth parameters for P. vulgaris in synthetic human urine (SHU) by testing different formulations of synthetic urine similar to real urine. Our preliminary results indicate that P. vulgaris achieve exponential growth in Enriched Synthetic Human Urine during a 12 h Growth Assay using Genesys UV-Vis Spectrophotometer, and the Colony-forming Units counting technique. Future bacterial growth experiments will be done with a more chemically consistent synthetic human urine with normal human urine components such as amino acids.