Isolation Of Algae-lysing Actinomycetes And Study Of The Regulation On Eutrophic Water

Recently, eutrophic and harmful algae blooms have attracted more concern in China due to their adverse effectson the environment. Therefore, it is imperative to seek effective methods to prevent algae blooms. Algae-lysing strains have attracted more attention as the biology of removing algae. Moreever, algae-lysing strains have broad application prospect.5 algae-lysing strains of aetinomyeetes were separated from the surrounding soil of WuHan, and were named as W4, SG-001, TD-3, HY-4 and XBC-1..SG-001 was the best one of lysing effect on Microcystis aeruginosa that identified as Streptomyces sp. The algicidal effect of SG-001 on Microcystis aeruginosa was discussed in this paper. The inhibition rate of Chlorophyll a was 81.99% to compared with the blank. The results showed the algal active substances present in the fermented liquid filtration, SG-001 had an excellent algicidal effect and 81.99% of chlorophyll a had been removed on the 5th day after addition of the fermented liquid filtration to compared with the blank. In addition, SG-001 was a certain inhibition to Microcystis aeruginosa, but promotion to Chlorella pyrenoidosa ,and it can be applied to nature water.To optimize the fermentation medium of the strain and to study the characteristics of algal active substance produced by strain SG-001. The optium condition for active production of SG-001 is determined by orthogonal design,and the best conditions included: glucose 10 g·L-1 , NH4Cl 1.0 g·L-1 , pH was 7.0, temperatute was 28℃and 4 days of fermentation time. The algal rate increased 26.29 % after the optimization. The algal active substance produced by SG-001 has better thermal stability, the inhibition rate was only decrease by 3.07% after 30 min of sterilization at 100℃, and its strong activity was at pH8.0. In this paper, the SG-001 fermented liquid filtration was added 5% to the mixed liquor to compare the competitive relationship of Microcystis aeruginosa and Chlorella pyrenoidosa, the results showed that Microcystis aeruginosa grow advantage in the first 2~6 days, but on the 8th day, Microcystis aeruginosa was basically inhibited by Chlorella pyrenoidosa, and the removing rate of nitrogen and phosphorus can reach 85% and 93.33%; At the same time, the competitive effects of nitrogen and phosphorus between Candida utilis and Microcystis aeruginosa in water were studied in this paper, the experimental results indicated that the removal efficiency of nitrogen and phosphorus was much better as the existence of C source, and C / N for the 2:1 is the best, and the removing rate of nitrogen and phosphorus was 87.45% and 83.73%, which increased by 56.36% and 22.93% respectively compared with the blank, and the growth of Microcystis aeruginosa has been inhibited.