IMS-2:

Eco-friendly approaches based on biological control to suppress harmful algal blooms

Harmful algal bloom has long been of concern over the world in general and South Korea in particular. In order to develop eco-friendly approach to suppress algal bloom, we isolated a novel bacterium, identified as Bacillus sp. (named T4) against Microcystis, the most common toxic microalgae. The bacterium could eliminate over 85% algal cells after 2 days, and the algicidal activity even reached 100% at day 5^th.Interestingly, our study showed that microalgal cells were killed through indirect attack by compound(s) secreted from bacterial culture. Furthermore, the isolated bacteria strain holds genes such as mlrA, mlrB, mlrC, and mlrD, responsible for microalgal toxin degradation and its toxin removal ability was confirmed by ELISA. On the other hand, zooplankton plays a pivotal role in aquatic food webs as a food source for fish as well as a grazer on microalgae. To further enhance the removal effect of algal bloom, we attempted to simultaneously apply zooplankton and T4. Data suggested that the simultaneous applications of both zooplankton and T4 strain led to the best performance against algal bloom. Our approach based on eco-friendly application of either bacteria, zooplankton, or together will open a new way to control harmful algal bloom.

keywords:Algal bloom,Algicidal activity,Microcystis,Bacteria,Zooplankton