Primary Research On Algae-lysing Substances From Actinomycetes AN02 And Controlling Effect Over Microcystis Aeruginosa By Chitosan-modified-actinomycetes-powder

With the eutrophication increasing,people are paying more attention to the water pollution caused by algae.Pollution caused by freshwater algae has become a global environmental issue so far.In recent years,since the control of water bloom by the physical and chemical method was less efficient,the method of microbiological to prevent and control harmful algae has gradually attracted people's attention.In order to explore the structure and chemical properties of extracellular algicidal substances from actinomycete AN02 that was isolated in our laboratory,the sterile filtrate obtained were dialysed,sedimentated by ethanol,extracted by organic solvents and antioxidant tested by ascorbic acid.The molecular weight of the extracellular algicidal substances of AN02 are less than 3.5kD.Ethanol can separate extracellular algicidal substances from other componets efficiently.The algicidal substances has weak polarity and can loss activity by oxidation.Different eluents and flow rates were tested for developing a good HPLC method to detect the algicidal substances in this crude extracts. The optimized analyzing conditions were on a C18 column,methanol/KH₂PO₄buffer in ratio of 10/90(V/V) as a mobile phase with a flow rate of 0.7 mL/min.The chromatogram was observed at 273 nm and the whole process was held at 25℃.A sort of algae-lysing-actinomycetes-powder was produced by spray drying process based on fermentation supernatant liquid of algae-lysing actinomycete AN02. About 90%of Microcystis aeruginosa cells could be removed after 4 days when the powder was added in proportion of 1:10000(m/m).While,when the chitosan-modified-algae-lysing-actinomycetes-powder(CMALAP) was added in proportion of 1:20000(m/m),about 90%of M.aeruginosa cells could be flocculated in 0.5 hour,and 80%could be lysed after 4 days.These powders are uniform,in small size, without live bacteria and less toxic.80%algicidal efficiency can be remained under room temperature for 100 days.The result indicated that the CMALAP can not only precipitate algae in short time,but also cause algae-lysing in long term,which implied that the powder has tremendous potential in algae-controlling application.