Lytics broadcasting system: A novel approach to disseminate bacteriophages for disinfection and biogenic hydrogen sulphide removal tested in synthetic sewage

Salim, Amrita; Shetty, K Sindhu; Febin, H.; Sameed, Nourin; Pal, Sanjay; Nair, Bipin G.; Madhavan, Ajith

doi:10.1016/j.rineng.2021.100314

Cited by 6 publications

(5 citation statements)

References 38 publications

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“…But the titre is dynamic since the device also accommodates the production host (6 × 10 9 CFU/mL) which results in infection and phage amplification. Passive diffusion from the BAR-LBS was previously reported to be 9.3 × 10 6 PFU/mL/h 19 , hence the efficiency of transfer from the device would maintain sufficient titre in wastewater. Nevertheless, the reduction in titre that was observed during the disinfection (when compared to the phage titre in the BAR-LBS) could hence be due to sequestration of phages or exhaustion of targets over a period of time.…”

Section: Discussionmentioning

confidence: 99%

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Salim

Madhavan

Subhash

et al. 2022

Sci Rep

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Bacteriophages are generally specific, and a cocktail of phages is needed to combat different bacterial targets. Their production usually requires pathogenic isolation hosts. We identified a novel strain, Escherichia coli ST155, that could serve as a production host for three different polyvalent phages (ϕPh_SE03, ϕPh_SD01, and ϕPh_EC01), thus superseding the use of individual isolation hosts. Upon propagation in E. coli ST155, the phages demonstrated differential intergeneric infectivity against Salmonella enterica, E. coli OP50, Shigella dysenteriae, E. coli MDR, and Acinetobacter baumannii. Phages were characterised based on morphology, latent period, burst size, the efficiency of plating, and restriction enzyme profile. Survival assay on Caenorhabditis elegans, the absence of Shiga toxin, and enterotoxigenic E. coli virulence genes indicated that E. coli ST155 could be non-pathogenic. Lack of antibiotic resistance and absence of functional prophages rendered the host suitable for environmental applications. As a proof-of-concept, phage ϕPh_SE03 was produced in ST155 by employing a unique Bacteriophage Amplification Reactor-Lytics Broadcasting System and was simultaneously disseminated into S. enterica augmented wastewater, which resulted in a 3-log reduction in 24 h. The study establishes the potential of E. coli ST155 as a phage production host thereby minimising the possibility of accidental release of pathogenic hosts into wastewater.

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Section: Discussionmentioning

confidence: 99%

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Salim

Madhavan

Subhash

et al. 2022

Sci Rep

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“…Phage cocktail formulations targeting these organisms that produce different biogenic malodourants, such as hydrogen sulphide, methanethiol, ammonia, and organic acids, need to be constituted to bring about aspirational malodour reduction. It is essential that phage dissemination systems, such as LBS (Lytics Broadcasting System) and BAR-LBS (Bacteriophage Amplification Reactor-LBS), along with appropriate production hosts, be in place to ensure efficient translation 69 . Expanding these systems with phage cocktail preparations, multiple malodourants can be targeted in wastewater efficiently and economically.…”

Section: Discussionmentioning

confidence: 99%

Mitigation of biogenic methanethiol using bacteriophages in synthetic wastewater augmented with Pseudomonas putida

Sarat,

Salim,

Pal

et al. 2023

Sci Rep

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Wastewater malodour is the proverbial ‘elephant in the room’ notwithstanding its severe implications on sanitation, health, and hygiene. The predominant malodorous compounds associated with wastewater treatment plants and toilets are volatile organic compounds, such as hydrogen sulphide, ammonia, methanethiol, and organic acids. Among them, methanethiol warrants more attention owing to its relatively low olfactory threshold and associated cytotoxicity. This requires an efficient odour-abatement method since conventional techniques are either cost-prohibitive or leave recalcitrant byproducts. Bacteriophage-based methodology holds promise, and the described work explores the potential. In this study, a non-lysogenous Pseudomonas putida strain is used as a model organism that produces methanethiol in the presence of methionine. Two double-stranded DNA phages of genome sizes > 10 Kb were isolated from sewage. ɸPh_PP01 and ɸPh_PP02 were stable at suboptimal pH, temperature, and at 10% chloroform. Moreover, they showed adsorption efficiencies of 53% and 89% in 12 min and burst sizes of 507 ± 187 and 105 ± 7 virions per cell, respectively. In augmented synthetic wastewater, ɸPh_PP01 and ɸPh_PP02 reduced methanethiol production by 52% and 47%, respectively, with the concomitant reduction in P. putida by 3 logs in 6 h. On extension of the study in P. putida spiked-sewage sample, maximum reduction in methanethiol production was achieved in 3 h, with 49% and 48% for ɸPh_PP01 and ɸPh_PP02, respectively. But at 6 h, efficiency reduced to 36% with both the phages. The study clearly demonstrates the potential of phages as biocontrol agents in the reduction of malodour in wastewater.

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“…We have previously designed a biofilter with a probiotic Lactobacillus & bacteriophage cocktail, which could reduce the coliform count by 2-log orders of magnitude [64]. We have also designed a novel lytics broadcasting system (LBS), which dispenses bacteriophage and other cell free lytic agents that could reduce the target bacterial load by 3 to 4 log orders of magnitude [65]. We believe that Pseudomonas being a very invasive and dominant species in their respective ecosystem, it would reduce the load even further [66].…”

Section: Discussionmentioning

confidence: 99%

Aspergillus niger Culture Filtrate (ACF) Mediated Biocontrol of Enteric Pathogens in Wastewater

Subhash

Babu

Vijayakumar

et al. 2022

Water

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Robust control of pathogens in sewage facilitates safe reuse of wastewater rich in valuable nutrients for potential valorization through biological means. Aspergillus niger is widely reported in bioremediation of wastewater but studies on control of enteric pathogens in sewage are very sparse. So, this study aimed at exploring the antibacterial and nematicidal activity of A. niger culture filtrate (ACF). Antibacterial activity of ACF on enteric pathogens (Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio cholerae, Salmonella enterica, Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, Klebsiella variicola) was determined by spectrophotometric growth analysis, resazurin based viability assay and biofilm formation assay. ACF showed inhibition against all enteric pathogens except Pseudomonas aeruginosa. Nematicidal studies on Caenorhabditis elegans showed 85% egg hatch inhibition and 52% mortality of L1 larvae. Sewage treatment with ACF at 1:1 (v/v) showed 2–3 log reduction in coliforms, Klebsiella, Shigella, Salmonella, S. aureus and Vibrio except Pseudomonas, indicating significant alteration of complex microbial dynamics in wastewater. Application of ACF can potentially be used as a robust biocontrol strategy against infectious microbes in wastewater and subsequent valorization by cultivating beneficial Pseudomonas.

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Lytics broadcasting system: A novel approach to disseminate bacteriophages for disinfection and biogenic hydrogen sulphide removal tested in synthetic sewage

Cited by 6 publications

References 38 publications

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Mitigation of biogenic methanethiol using bacteriophages in synthetic wastewater augmented with Pseudomonas putida

Aspergillus niger Culture Filtrate (ACF) Mediated Biocontrol of Enteric Pathogens in Wastewater

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