Nutrient management is a critical issue for Water Resource Recovery Facilities, and sidestream treatment technologies to reduce nutrient loads often focus on liquid sidestream and require external carbon sources. Post...

A year‐long sampling campaign at nine water resource recovery facilities (WRRFs) was conducted to assess the treatability and fate of bacterial indicators, viral indicators, and viruses. Influent concentrations of viral indicators (male‐specific and somatic coliphages) and bacterial indicators (Escherichia coli and enterococci) remained relatively constant, typically varying by one order of magnitude over the course of the year. Annual average bacterial indicator reduction ranged from 4.0 to 6.7 logs, and annual average viral indicator reduction ranged from 1.6 to 5.4 logs. Bacterial and viral indicator reduction depended on the WRRF's treatment processes, and bacterial indicator reduction was greater than viral indicator reduction for many processes. Viral reduction (adenovirus 41, norovirus GI, and norovirus GII) was more similar to viral indicator reduction than bacterial indicator reduction. Overall, this work suggests that viral indicator reduction in WRRFs is variable and depends on specific unit processes. Moreover, for the same unit treatment process, viral indicator reduction and bacterial indicator reduction can vary.Practitioner points A year‐long sampling campaign was conducted at nine water resource recovery facilities (WRRFs).The treatability and fate of bacterial indicators, viral indicators, and viruses were assessed.Viral indicator reduction in WRRFs is variable and depends on specific unit processes.For the same unit treatment process, viral indicator reduction and bacterial indicator reduction can vary.

Since the early 1920s there has been an interest in using bacteriophages (phages) for the control of bacterial pathogens. While there are many factors that have limited the success of phage bio-control, one particular problem is the variability of outcomes between phages and bacteria. Specifically, there is a significant need for a better understanding of how initial phage concentrations affect long-term bacterial inhibition. In work reported herein three phages were isolated for Escherichia coli K12, Pseudomonas aeruginosa PAO1, as well as Bacillus cereus and bio-control experiments were performed with phage concentrations ranging from 10(5) to 10(8) plaque forming units per mL over the course of 72 h. For four of the nine phages isolated there was a linear relationship between inhibition and phage concentration, suggesting the effect of phage concentration is important at longer time scales. For three of the isolated phages, phage concentrations had no effect on bacterial inhibition suggesting that even at the lowest concentration the method of action was saturated and lower concentrations might still be effective. Additionally, a cocktail was created and was compared to the previously isolated phages. There was no statistical difference between the cocktail and the best performing phage highlighting the importance of selecting the appropriate phages for treatment. These results suggest that, for certain phages, there is a strong relationship between phage concentration and long-term bacterial growth inhibition and the initial phage concentration is an important indicator of the long-term outcome.

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Invasive Lactobacillus bacteria inhibit ethanol fermentations and reduce final product yields. Due to the emergence of antibiotic resistant strains of Lactobacillus spp., alternative disinfection strategies are needed for ethanol fermentations. The feasibility of using the bacteriophage (phage) 8014-B2 to control Lactobacillus plantarum in ethanol fermentations by Saccharomyces cerevisiae was investigated. In 48 h media-based shake flask fermentations, phages achieved greater than 3-log inactivation of L. plantarum, protected final ethanol yields, and maintained yeast viability. The phage-based bacterial disinfection rates depended on both the initial phage and bacterial concentrations. Furthermore, a simple set of kinetic equations was used to model the yeast, bacteria, phage, reducing sugars, and ethanol concentrations over the course of 48 h, and the various kinetic parameters were determined. Taken together, these results demonstrate the applicability of phages to reduce L. plantarum contamination and to protect final product yields in media-based fermentations.

The adoption of antisense gene silencing as a novel disinfectant for prokaryotic organisms is hindered by poor silencing efficiencies. Few studies have considered the effects of off-targets on silencing efficiencies, especially in prokaryotic organisms. In this computational study, a novel algorithm was developed that determined and sorted the number of off-targets as a function of alignment length in Escherichia coli K-12 MG1655 and Mycobacterium tuberculosis H37Rv. The mean number of off-targets per a single location was calculated to be 14.1 ± 13.3 and 36.1 ± 58.5 for the genomes of E. coli K-12 MG1655 and M. tuberculosis H37Rv, respectively. Furthermore, when the entire transcriptome was analyzed, it was found that there was no general gene location that could be targeted to minimize or maximize the number of off-targets. In an effort to determine the effects of off-targets on silencing efficiencies, previously published studies were used. Analyses with acpP, ino1, and marORAB revealed a statistically significant relationship between the number of short alignment length off-targets hybrids and the efficacy of the antisense gene silencing, suggesting that the minimization of off-targets may be beneficial for antisense gene silencing in prokaryotic organisms.

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