Algae. 2004; 19(2): 145-148.
Optimal Growth Conditions for the Two Euryhaline Cyanobacterial Clones, Anabaena sp. CB-MAL21 and CB-MAL22 Isolated from Mankyeong Estuary, Korea
Young Geel Kim, Geum Og Myung, Wonho Yih* and Yoon Keun Shin1
Department of Oceanography Kunsan National University, Kunsan, 573-701 and 1Department of Environmental Engineering, Sangji University, Wonju, 220-702, Republic of Korea
As a result of the 2-year monthly monitoring of the phytoplankton community at 3 stations in Mankyeong Estuary, Korea, we learned that cyan bacterial species of the genus Anabaena occurred at most sampling points with huge salinity differences (0.1-32.5 psu). We isolated several clones of Anabaena spp. from the monitoring stations, and screen out two euryhaline and nitrogen-fixing Anabaena clones, CB-MAL21 and CB-MAL22. The two clones were grown under various environmental gradients such as temperature (20, 30, 35 and 40oC), salinity (0, 2, 5, 15 and 30psu), and PO3-4-P concentration (0, 1.6, 8.0, 40 and 200 uM). Growth of CB-MAL21 and CB-MAL22 was measured by daily monitoring of chlorophyll fluorescence from each experimental culture for more than three serial transfers. Both the two experimental clones did not grow at 0psu. Maximal growth rates of the two clones were markedly reduced at lower PO3-4-P concentrations showing negligible growth at 0 and 1.6 uM. However, growth of CB-MAL21 was not affected by low NO-3concentration in culture media, showing the nitrogen-fixing ability. Maximum biomass yields of the two clones decreased dramatically at 35 and 40 . Optimal growth conditions for the two experimental clones were determined to be 20-30oC, 40 uM PO3-4-P, and wide salinity range from 5.0 to over 30psu. Best growth of CB-MAL21 was shown at (20oC-15psu), which is less saline and cooler condition than those (i.e., 30oC-30psu) for the best growth of CB-MAL22. The euryhaline and nitrogen-fixing CB-MAL21 strain thus can be a candidate laboratory culture for the future cyan bacterial marine biotechnology in temperate coastal waters.
Keywords : cyanobacterial clone, euryhaline, Mankyeong Estuary, nitrogen fixing, optimal growth