Effects Of Di-butyl Phthalate On Growth And Enzymatic Antioxidants Of Microcytis Aeruginosa

Di-butyl phthalate (DBP) is one of the phthalate esters (PAEs), and it has been used widelyas plasticizer. Now, DBP has been extensively measured in the air, water, or even in the humanbody. DBP has been recognized as an environmental hormone, and it can be accumulated in theorganisms, and can be toxic to them. As an allopathic substance, DBP may inhibit the growth ofalgae cells to some extent. In this paper, the effects of di-butyl phthalate on growth andenzymatic antioxidants of Microcytis aeruginosa were studied. The main conclusions were asfollows:(1) When DBP was less than4mg/L, it could promote the growth of Microcystisaeruginosa, and improved the antioxidant enzyme activities, but no significantly doserelationship effect was observed. When its concentration exceeded8mg/L, DBP could inhibitthe Microcystis aeruginosa.(2) The inhibition of di-butyl phthalate on growth and enzymatic antioxidants ofMicrocytis aeruginosa was in high concentration groups, and its toxic effect was not obvious.(3) Besides the photosynthesis system, the inhibition of DBP might occur on antioxidantdefense system and biofilm systems. When DBP exceeded8mg/L, its inhibition was observedon photosynthesis system firstly. DBP reduced the photosynthetic pigment content ofMicrocystis aeruginosa, and then inhibited the photosynthesis system. Also, DBP arrested algaecell division, and affected the biofilm adversely, reducing the rate of the growth. At the sametime, DBP reduced the antioxidant enzymes of Microcystis aeruginosa, which resulted inoxidative stress, with the increasing of active oxygen and the inhibiting of algae cell growth.(4) In most source water, the maximum detection values of DBP were below4mg/L,which showed that in the water environment of China, the concentration of DBP might promotethe most of Microcystis aeruginosa water blooms.In this paper, the effect of DBP on the growth and enzymatic antioxidants of Microcytisaeruginosa were studied in order to provide important evidences for researches on the toxiceffect of PAEs to biology.