The inhibitory effects of palmitic acid and stearic acid on Microcystis aeruginosa

The inhibitory effects of palmitic acid and stearic acid on toxic Microcystis aeruginosa were studied,and the relationship between the structures of the long-chain saturated fatty acids and the inhibitory effects was compared.Our experiment selected toxic Microcystis aeruginosa FACHB-912,which was bought from Institute Hydrobiology of Chinese Academy of Sciences,and made it in the logarithmic phase.The four concentrations of palmitic acid and stearic acid in the algal solutions were:30 mg·L-1,60 mg·L-1,90 mg·L-1 and 120 mg·L-1.The experimental time was six days,and we measured A650nm,chlorophyll a and phycocyanin of the alga every day.When the experiment was finished,we used SPSS (13.0 Version) and DPS (7.05 Version) to analyze the significant differences between the alga treated by the fatty acids and the control.The result showed that the four concentrations of the two saturated fatty acids could all inhibit the growth of the alga obviously.The higher the concentration,the obvious the inhibitory effect was found.Also,under the same concentration,the inhibitory effect of palmitic acid on the alga was more obvious than that of stearic acid.Our experiment also had two innovations:①Because long-chain saturated fatty acids cannot be dissolved in water,we used ethanol to dissolve them.②Because ethanol solution of long-chain saturated fatty acids cannot be sterilized by autoclaves,we used microfiltration membranes to sterilize the fatty acid solutions.