16 Jun 2025

Development of Innovative Cyanophage-Based Biotechnology for Harmful Cyanobacterial Blooms Mitigation: Interim Progress Report

Abstract: Freshwater harmful cyanobacteria blooms (HCBs) are caused by toxin-producing cyanobacteria. Current efforts to prevent and mitigate HCBs include physical and chemical treatments, as well as manipulating the nutrient input and biological ecosystem of impacted water bodies. However, the development of remediation technologies lags behind the increasing frequency, prevalence, and severity of HCBs and their associated adverse health effects and socioeconomic losses. It is difficult to control the side effects of these remediation technologies due to their interactions with nontarget species, including microbes, plants, and animals. This project proposed the use of cyanophages, an abundant natural resource, to control HCBs in a target-specific manner. Here, the results of Year 1 of this effort are reported. Environmental field samples were collected, processed, and characterized morphologically and molecularly. Assays were refined for isolating and characterizing lytic environmental cyanophages. Cryopreservation methods were tested on pure cyanobacteria cultures, while well-characterized cyanophages were used to verify methods to retain infectivity for over 1 year. Methods to induce lysogenic phages to enter their lytic cycle were also explored. The goal was to develop a novel cyanophage-based biotechnology for HCBs mitigation by turning field-collected cyanophages into genetically modified (GM) or non-GM biocontrol agents to disrupt HCBs.