2-Methylisoborneol (2-MIB) Excretion by <i>Pseudanabaena</i> <i>yagii</i> under Low Temperature
2021
Ju-Yong Jeong | Sang-Hoon Lee | Mi-Ra Yun | Seung-Eun Oh | Kyong-Hee Lee | Hee-Deung Park
Outbreaks of 2-methylisoborneol (2-MIB) contamination in drinking water sources cause inconvenient odor issues in the water distribution system. In this study, microscopy-based isolation with physiological and molecular phylogenetic characterization were performed to investigate and characterize the 2-MIB odor producers that caused an odor problem in the freshwater system of the North Han River in the autumn of 2018. A benthic cyanobacterium was isolated from 2-MIB odor-issue freshwater samples and was found to be phylogenetically affiliated with <i>Pseudanabaena yagii</i> (99.66% sequence similarity), which was recorded in South Korea for the first time. The 2-MIB synthesis gene sequences from the odor-issue freshwater samples showed 100% similarity with those in the <i>P. yagii</i> strains. Protein sequences of 2-MIB synthase observed in the genome of the isolated strain showed structural and functional characteristics similar to those observed in other <i>Pseudanabaena</i> species. The 2-MIB production rate increased slowly during mat formation on the vessel wall; however, it rapidly increased after the temperature dropped. The 2-MIB gene was continuously expressed regardless of the temperature changes. These results suggest that the 2-MIB odor issue in the North Han River might be caused by the release of 2-MIB from the mat-forming <i>P. yagii</i> species in a low-temperature freshwater environment.
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