Project description:Many biomonitoring tools/approaches have been proposed to assess presence of endocrine active chemicals (EACs) and their biological effects in the field. Although these tools have provided valuable information, they are often limited by their specificity for certain groups of EACs and they may not account for interactions between EACs. This study aims to evaluate utility of transcriptomic and metabolomic technologies for effects monitoring in the field, and to advance integration of omic and environmental chemistry data sets. The objective was to utilize transcriptomic biomonitoring to determine the relative contribution of wastewater treatment plant effluents to biological effects observed in fish exposed to ambient waters receiving the effluents. Adult male fathead minnow were exposed to treated wastewater effluent or stream water up or downstream the plant in three different watersheds for 4 days. After exposure, the liver of 5-7 fish per treatment per site (i.e 19-21 fish from each watershed) were analyzed by microarrays. The transcriptomic profiles were compared to control fish exposed to Lake Superior filtered water.
Project description:Bio-augmentation could be a promising strategy to improve processes for treatment and resource recovery from wastewater. In this study, the Gram-positive bacterium Bacillus subtilis was co-cultured with the microbial communities present in wastewater samples with high concentrations of nitrate or ammonium. Glucose supplementation (1%) was used to boost biomass growth in all wastewater samples. In anaerobic conditions, the indigenous microbial community bio-augmented with B. subtilis was able to rapidly remove nitrate from wastewater. In these conditions, B. subtilis overexpressed nitrogen assimilatory and respiratory genes including NasD, NasE, NarG, NarH, and NarI, which arguably accounted for the observed boost in denitrification. Next, we attempted to use the the ammonium- and nitrate-enriched wastewater samples bio-augmented with B. subtilis in the cathodic compartment of bioelectrochemical systems (BES) operated in anaerobic condition. B. subtilis only had low relative abundance in the microbial community, but bio-augmentation promoted the growth of Clostridium butyricum and C. beijerinckii, which became the dominant species. Both bio-augmentation with B. subtilis and electrical current from the cathode in the BES promoted butyrate production during fermentation of glucose. A concentration of 3.4 g/L butyrate was reached with a combination of cathodic current and bio-augmentation in ammonium-enriched wastewater. With nitrate-enriched wastewater, the BES effectively removed nitrate reaching 3.2 mg/L after 48 h. In addition, 3.9 g/L butyrate was produced. We propose that bio-augmentation of wastewater with B. subtilis in combination with bioelectrochemical processes could both boost denitrification in nitrate-containing wastewater and enable commercial production of butyrate from carbohydrate- containing wastewater, e.g. dairy industry discharges. These results suggest that B. subtilis bio-augmentation in our BES promotes simultaneous wastewater treatment and butyrate production.
