Isolation Of Two Marine Algicidal Bacteria And Their Algicidal Characteristic

We taking water samples from XiangShan har, then concentrated by backflushing ultrafiltration, and then to infect algae cells, finally we got two novel algicidal bacteria named MI and JI.The MI has algicidal effect to Chaetoceros muelleri, Prorocentrum minimum, and Skeletonema Costatum 1115,which has the best effect to Chaetoceros muelleri. The Ch1.a was reduced 70.68% to Chaetoceros muelleri in 72 hours. By Optical microscope observation,MI is a mixture bacteria at at least two different forms. By electron microscope observation,the bacteria neither invasive algae cells in the body nor around the algal cell, which means that the bacterium MI is a kind of bacterium which could competed for the nutrients with algal cells.The JI has algicidal effect to Isochrysis galbana, Prorocentrum minimum, P. donghaiensis and Chaetoceros curvisetus. The Ch1.a was reduced 74.03% to Isochrysis galbana in 96 hours. The culture of bacteria JI filtered by the 0.22μm membrane, and its filtrate has no algicidal phenomenon to its host.But the eluent from membrane has algicidal phenomenon to its host, which means that the bacterium JI is a kind of bacterium which can lyse Isochrysis galbana for the direct contact with the algal cells or competed with algal cells for the nutrients.According to the principle of Microbial continuous culture and the operation mechanism of Fermenter.We self-designed a microorganisms in continuous culture device.It can raise the hoste to Logarithmic phase quickly,and can output the algicidal bacteria at 105Titer.