Algae-lysing characteristics of an algicidal bacterium G2 from reservoir sediment

Microcystis aeruginosa can cause algal blooms, which has been a serious threat to the water environment. Microbial algae removal is a technology with good application prospects. In this study, we isolated a new algae-dissolving bacterium G2 from the reservoir substrate of Xi'an of Shaanxi Province, identified as Cellvibrio sp. according to 16S rDNA sequence analysis (GenBank accession No.: MW221316), and investigated the feasibility of G2's solubilizing M. aeruginosa. Results show that G2 solubilized algae by secreting extracellular substances indirectly, and it had the best removal effect on algae during the stabilization period. Increasing G2 dosing ratio (>10%) contributed to the effect of algae dissolution. G2 was sensitive to the change of temperature, and the algae removal rate reached (59.42±0.88)% and (63.10±1.42)% at 5 and 25 ℃, respectively. The removal efficiency was poor at temperatures higher than 75 ℃. The pH and light had no significant influences on the algae removal effect, and G2 had strong tolerance to acid and alkali (pH 3−11). In conclusion, G2 can inhibit the growth of M. aeruginosa efficiently, so it is a promising biocontrol agent to mitigate cyanobacterial blooms.