Studies on sensitivity of Microcystis aeruginosa to four kinds of antibiotics

Microcystis is the most common dominant species in bloom-forming cyanobacteria, which are influenced by some environmental factors. Among these factors, epiphytic bacteria are one of the important biotic factors for Microcystis growth. In this paper, four kinds of antibiotics (penicillin, chloramphenicol, polymyxin, rifampin) were used to inhibit epiphytic bacteria of Microcystis aeruginosa, aiming to study sensitivity and growth condition of Microcystis aeruginosa under different antibiotics concentration. Results showed that lethal concentration sequence of these antibiotics for Microcystis aeruginosa was as following: penicillin (100µg/mL) > chloramphenicol (10µg/mL) > polymyxin (1µg/mL) > rifampin (0.1µg/mL). Under the lethal concentration, no significant differences were observed in algal growth curves among control and treatment groups (P >0.05), thus influences of epiphytic bacteria on the growth of Microcystis aeruginosa were not obvious.