Identification and characterization of a novel indigenous algicidal bacterium <i>Chryseobacterium</i> species against <i>Microcystis aeruginosa</i>

Abstract

Harmful <i>Microcystis aeruginosa</i> blooms occurred frequently in many eutrophic lakes and rivers with resultant serious global environmental consequences. Algicidal bacteria may play an important role in inhibiting the growth of <i>Microcystis aeruginosa</i> and are considered as an effective method for preventing the appearance of blooms. In order to counteract the harmful effects of <i>Microcystis aeruginosa</i>, a critical step is to identify, isolate and characterize indigenous algicidal bacteria. This study aimed to isolate a novel indigenous algicidal bacterium identified as <i>Chryseobacterium</i> species based upon its 16S rDNA sequence analysis, and determine whether this bacterium was effective in lysing <i>Microcystis aeruginosa</i> FACHB 905. The influence of environmental factors including temperature, pH, quantity of <i>Chryseobacterium</i> species as well as <i>Microcystis aeruginosa</i> concentration were examined with respect to algae-lysing properties of this bacterial strain. Data demonstrated that the highest algae-lysing activity of 80% against <i>Microcystis aeruginosa</i> FACHB 905 occurred within 72 hr. In addition, the algae-lysing activities of <i>Chryseobacterium</i> species cells were significantly higher than those of cell-free supernatant. In conclusion, data showed the algicidal bacterium <i>Chryseobacterium</i> species exhibited potent <i>Microcystis aeruginosa</i>-lysing activities and attacked <i>Microcystis aeruginosa</i> directly suggesting this algicidal bacterium may be potentially useful for reducing the number of harmful <i>Microcystis aeruginosa</i> blooms.