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.

Project description:Characterization of microbial communities at the genomic, transcriptomic, proteomic and metabolomic levels, with a special interest on lipid accumulating bacterial populations, which are naturally enriched in biological wastewater treatment systems and may be harnessed for the conversion of mixed lipid substrates (wastewater) into biodiesel. The project aims to elucidate the genetic blueprints and the functional relevance of specific populations within the community. It focuses on within-population genetic and functional heterogeneity, trying to understand how fine-scale variations contribute to differing lipid accumulating phenotypes. Insights from this project will contribute to the understanding the functioning of microbial ecosystems, and improve optimization and modeling strategies for current and future biological wastewater treatment processes. This project contains datasets derived from the same biological wastewater treatment plant. The data includes metagenomes, metatranscriptomes, metaproteomes and organisms isolated in pure cultures. Characterization of microbial communities at the genomic, transcriptomic, proteomic and metabolomic levels, with a special interest on lipid accumulating bacterial populations, which are naturally enriched in biological wastewater treatment systems and may be harnessed for the conversion of mixed lipid substrates (wastewater) into biodiesel. The project aims to elucidate the genetic blueprints and the functional relevance of specific populations within the community. It focuses on within-population genetic and functional heterogeneity, trying to understand how fine-scale variations contribute to differing lipid accumulating phenotypes. Insights from this project will contribute to the understanding the functioning of microbial ecosystems, and improve optimization and modeling strategies for current and future biological wastewater treatment processes. This project contains datasets derived from the same biological wastewater treatment plant. The data includes metagenomes, metatranscriptomes, metaproteomes and organisms isolated in pure cultures.

Project description:Three surface waters in Gainesville, Florida were used in a 48 hour whole effluents exposure to assess gene expression profiles of male fathead minnow liver. Microarray analysis was used to determine changes in gene expression of exposed fish to waters from a site downstream of a wastewater treatment plant (streamwater), a wastewater treatment plant (wastewater), and a lake (stormwater). Differences in gene expression between fish exposed to collected waters and controls were observed. Number of altered genes and biological processes were 1028 and 18 for stormwater; 787 and 19 for streamwater; and: 575 and 12 for wastewater. In general, the effects observed in all exposed fish were related with fatty acid metabolism, DNA repair, oxidation-reduction process, cell wall catabolic process and apoptosis. All exposed fish showed altered expression of genes related with DNA damage repair. In particular fish exposed to stormwater and streamwater showed downregulation of several key intermediates transcripts of cholesterol. The presence and environmental persistence of perfluorinated chemicals (PFCs) in these waters, the resemblance in known effects on transcripts with those found in this study, suggest that the set of genes differentially regulated in fathead minnows after 48 hours of exposure may be attributed to exposure to PFCs. Three surface water sites were chosen for effluent collection in Gainesville, Florida: A lake (stormwater), surface water downstream of a wastewater treatment plant (streamwater), and a wastewater treatment plant effluent used for landscaping irrigation (wastewater). Water from each site was collected two days prior to the fish exposure experiment using Chemfluor ® tubing and a 120 liters steel barrels coated with polyester resin (gel coat) to avoid cross-contamination. Three barrels for each effluent were collected during day 1. Water from the barrel was transported to the laboratory and pumped into four fiberglass cylinders in the aquatic toxicology facility. Water from each cylinder was then pumped into four replicate aquariums per treatment and kept for 1 day without fish (pre-treatment). On day 2, four male fathead minnows from a common tank were transferred to each replicate aquarium and kept for 48 hours, with one 75% water change after first 24 hours. The exposure system consisted of 40 L glass aquaria. Each exposure was conducted in quadruplicate and each aquarium contained the four male fish in 25 L of treatment water . The water used in the control treatment was carbon filtered, dechlorinated tap water. The positions of the treatment tanks were randomized and test initiation times were staggered to ensure an exposure/sampling interval of 48 h. The fish were not fed during the experiment. The temperature range of the water was 24-26 °C with a photoperiod of 16 h light: 8 h dark. Liver was isolate from 4 males indviduals for each treatment except for control group (3 individuals).

Project description:In the search for sustainable drinking water, many countries are weighing up the benefits of advanced treatment technologies as a proactive measure to assist with the transformation of treated wastewater into a source of water used for the production of potable water. We investigated the biological effects along a pilot plant with an advanced water treatment process, using zebrafish embryos at different stages of development. The study took an innovative approach, comparing phenotypic observations with whole genome responses. This enabled us to keep an open mind about which chemicals might be influencing the biological activity. There was no evidence of acute toxicity at any stage of treatment, but distinctive abnormalities – skeletal, cardiovascular and pigmentation – occurred in a small proportion of embryos along the treatment process, and in a tap water, that were not detected in the aquarium water control. Reverse osmosis (RO) reduced the concentration of measured chemical contaminants in the water the most, whilst eliminating the occurrence of abnormalities detected in the fish. In contrast, advanced oxidation appeared to reverse the benefits of RO treatment by increasing the frequency of teratogenic and sub-lethal abnormalities seen in embryos. Genomic analysis found alterations to the retinoid system, which was consistent with the teratogenic abnormalities observed. In addition, we found evidence of changes to metabolic pathways, including tryptophan metabolism associated with the production of melatonin required for the control of normal circadian rhythms. Although we cannot extrapolate these preliminary findings in zebrafish embryos to human or environmental health, we show that underexplored forms of biological activity (that existing Test Guidelines are not designed to capture) occur in treated wastewater effluent, and/or may be created depending on the type of advanced treatment process used. Although the identity of the culprit chemicals are unknown at this time, our innovative approach highlights the need for more research into the effects of chemicals on the retinoid system (and metabolism).

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