Effects Of Cultivate Conditions On Antialgal Activity Of Fusarium Moniliforme Extracts

Along with fast development of global economic, the environmental pollutionproblem is serious day by day. The eutrophication is one of important factors for affectingwater quality. The gradualness of blue-green algae is the most commonly phenomenon ofthe eutrophication. The eruption and growth of algae are not only consuming the massivedissolved oxygens in the water, but also produce algae toxins, then influence survival rateof other water living things. Therefore, the research and development of the algaecontrolling technology in the eutrophication have received widespread attention. Thisarticle took Fusarium moniliforme which isolated from the eutrophication water sample asthe object of study, took the Chlorella pyrenoidosa as the target, studied the antialgal rateagainst Chlorella pyrenoidosa of culture conditions on fusarium moniliforme producingextraction, proposed the optimized fermentation condition of Fusarium moniliforme, andappraised the antialgal rate against Scenedesmus obliquus of culture conditions onfusarium moniliforme producing extraction.The main results were as following:1. Using the lineation law, four fungi which were SA, SB, SC and Fusariummoniliforme (identified by the Chinese Academy of Science Microorganism Research) hadisolated and purified from water sample. And the secondary metabolites of four fungi hadextracted by homogenation law with ethyl acetate. The biological assay results of thesecondary metabolites made from four fungi under the0.25~1.0g/L showed that: SA:-69.38%~11.23%, SB:-23.84%~-17.95%, SC:22.33%~-1.35%, Fusarium moniliforme:42.04%~87.09%, respectively, which took Chlorella pyrenoidosa as the target.2. The results of optimized temperature and pH for raising Fusarium moniliformefermentation fluid were screened by the single factor screening experiment, which were22℃and8, respectively. Under22℃, the antialgal rate against Chlorella pyrenoidosa was92.18%, the extracts were0.09g/L. Under the pH=8, the antialgal rate against Chlorellapyrenoidosa was82.89%, the extracts were0.12g/L. The results of optimized definedmedium for raising Fusarium moniliforme fermentation fluid were screened and showedthat: malt sugar (2%), protein peptone (2%), and CaCl2+MgSO4(0.1%+0.05%), by theorthogonal design experiment. And under these defined medium, the antialgal rate againstChlorella pyrenoidosa was88.71%, the extracts were0.28g/300mL. As the same way, theresults of optimized fermentation condition for raising Fusarium moniliforme fermentation fluid were screened and showed that: vaccination quantity=13, nutrientsolution=160mL/250mL, vibration velocity=140r/min by the orthogonal design experiment.And under these fermentation condition, the antialgal rate against Chlorella pyrenoidosawas87.15%, the extracts were0.20g/300mL.3. The result of optimized extraction process for raising Fusarium moniliformefermentation fluid was screened: Vfermentation fluid:Vextractant=2:1by ethyl acetate withdraws4times repeatedly, by the orthogonal design experiment. And its antialgal rate againstChlorella pyrenoidosa was85.08%, the extracts were0.14g/300mL.4. The results of dosage effect showned that was an obvious dose-effect relationshipbetween the extracts from Fusarium moniliforme fermentation fluid and the antialgal rate.The EC50against Chlorella pyrenoidosa, Scenedesmus obliquus, and their mix-algae were0.33g/L,0.34g/L,0.42g/L, respectively.5. Observed the algae cells through SME (scanning electron microscope), incomparison with the algae cells shape which were not operated by extracts made fromFusarium moniliforme, the algae cells shape which were operated by extracts made fromFusarium moniliforme were changed as followinng: the shape were fuzzyâ†'the cell wallwere brokenâ†'the whole cells were gradually gone to dissolveâ†'the cells were completelydissociated.The results of this article had provided a basis for separating and purifyingantialgal active secondary metabolite from Fusarium moniliforme, which has an veryimportant reference meaning for further developing algaecide making from livingresources.