Algicidal effect of bacteria CZBC1 on Microcystis aeruginosa in chloride type saline-alkali water

In order to develop the algaolytic bacterial agent for chloride type saline-alkali water, we selected the algaolytic bacterial strain Bacillus cereus CZBC1, and investigated the algaolytic effects of the filtrate group (FG), the bacterium group (BG), and the bacterial solution group (BSG) in the chloride type saline-alkali water with the initial density of Microcystis aeruginosa of 10⁵ and 10⁶ cell·mL⁻¹, respectively. The results show that the strain CZBC1 had both direct and indirect ways of dissolving microalgae. When strain CZBC1 in FG, BG and BSG acted on M. aeruginosa, their microalgal cells could deform, fade or rupture, playing a good role in dissolving algae in chloride type saline-alkali water. When the initial microalgal density was 10⁵ cell·mL⁻¹, the microalgal density could be reduced to 2.30×10 cell·mL⁻¹ in BSG and 1.27×10² cell·mL⁻¹ in BG on the 6^th day, which were extremely significantly lower than that in the control group (CG) (3.65×10⁵ cell·mL⁻¹, p<0.01), and the highest algicidal rates in both groups could reach over 99%. When the initial microalgal density was 10⁶ cell·mL⁻¹, the microalgal density could be reduced to 8.30×10⁵ cell·mL⁻¹ in BSG on the 6^th day, which was significantly lower than that in CG (3.17×10⁶ cell·mL⁻¹, p<0.05), and its highest algicidal rate could reach over 78.8%. The algicidal effect of BSG was better than that of BG and FG. The results indicate that in order to prevent and control microcystis blooms in chloride type saline alkali ponds, it is recommended to prioritize prevention and regularly apply algicidal bacteria CZBC1 to prevent and control the formation of harmful algal blooms.