Screening And Preliminary Application Of Algicidal Bacteria From Eutrophic Water In Cold Region

Along with the progress of the society, the "three wastes" disrupted the nature eternal cycle.Excessive fertilization, untreated sewage shall be discharged and atmospheric deposition is theresult of worldwide, especially in developing countries bloom phenomenon serious the initiator ofevil. Safety problems of water bloom algae overgrowth and the aquatic ecosystem to be solved. Inthe traditional method for treatment of bloom, the effect is not ideal condition, prevention andcontrol means to microbial bloom be imperative. Algae lysing bacteria with specific removalcharacteristics of bloom algae, algal scheme is environment friendly, low cost, high efficiency, hasbeen deeply researched and widely recognized by domestic and foreign scholars. With the rapiddevelopment of the bioremediation of eutrophicated water by microbial treatment technology, waterbloom, already tended to be mature, is expected to put into practice. In this study, using isolatedfrom Jilin Agricultural University in the algae lysing bacteria, numbered A1, discusses themechanism of separation was dissolved in natural water algae and pure Microcystis aeruginosaaspects and algicidal characteristics, and the algicidal substances identification and toxicity analysis.The main results are as follows:1Separation of mixed algae from a eutrophic water in Jilin Changchun and to study with it.Observation of microalgae and microalgae growth characteristics, the experimental results showthat the mixed algae maximum absorption wavelength is between600nm-760nm to680nm. For thepurchase of Microcystis aeruginosa from China algae Library of928to study and draw Microcystisaeruginosa928growth curve, found that the algae in the natural growth condition about4days inlogarithmic growth phase, the OD680is about0.2.2Will be collected in the water sample pretreatment of different water extracted from thebacteria and select the similar morphology and water common bacteria dominated by algicidalexperiments, from which a strain screened with bacterial A1algicidal characteristics from a largepond in Jilin province. The chlorophyll a content measured algal cell growth, ultimately determinethe strain A1of bacteria suspension and aseptic broth were lytic effect, and the sterile fermentationliquid algicidal effect more obvious. The bacteria is higher than that in bacterial concentration1×105CFU/mL, had significant inhibitory effect on microalgae, bacteria and A1cell can use theMicrocystis aeruginosa yellow after the algae cell extracellular metabolites and algal residues,especially the algal residue as carbon source in the medium of vigorous growth, and can secretegreen pigment.3Preliminary identification of A1, and identify the green pigment secretion in its growthprocess, the identification of the A1strain was gram negative, its green metabolites as pyocyanin, the fungus ability was the strongest breed in the neutral condition, and the production of pyocyaninamount is maximum, cultured in the same conditions, strain A1of glucose, beef extract, starchmedium sterile broth pyocyanin content is higher. The strain in the culture medium after the end ofthe pH reached8, therefore, in the culture of A1bacteria process may have the ability to regulatethe pH of the surrounding environment.4The sterile fermentation liquid of A1strains algicidal characteristics to develop specificanalysis, found by the disposable dosing sterile fermentation liquid of algicidal test algicidal effectis better than the continuous batch adding; the algae fluid of the same volume, adding greaterproportion of algicidal effect is better, the initial quantity of adding sterile the greater thefermentation liquid of microalgae removal rate is higher; influential damps the algae effect ofdifferent algae concentration on the strain A1, with the same volume, A1aseptic broth sameconcentration when the initial concentration of algae liquid is low, algicidal effect; light stability ofstrain A1sterile broth, thermal stability and pH stability is good, the strain A1sterile fermentationliquid as non protein substances, stable and not easy metamorphism; change the effect of mediumcomponents on A1metabolism and effects on the algae lysing effect, there are significantdifferences between different culture of A1bacteria produce pyocyanin amount, including glucose,beef paste and starch culture inhibitory effects of A1fungi fermentation liquid based liquidfermentation of microalgae is best, as mentioned above, three groups of strains A1the sterilefermentation liquid pyocyanin higher content of the algal culture under the same conditions Theeffect is better also; finally, to explore the relationship between the different culture medium ofstrain A1from metabolites of pyocyanin amount corresponding algicidal effect, we found that theyhad a significant negative correlation, the correlation coefficient is-0.709*.