The algicidal activity of Gb03 strain was investigated against other harmful algae blooms species.
Calculation of algicidal activity of Gb-03 strain was done by using the following equation  : Algicidal activity (%) = (1 - Tt/Ct) x 100.
Relationship of algicidal activity and bacterial growth:
The algicidal activity of Gb03 strain was increasing proportionally to the optical density (figure.
malayensis culture, the algicidal activity increase by increasing the volume of culture supernatant of Gb03 strain.
Algicidal activity of Gb03 strain culture supernatant on other harmful algae blooms:
Filtrated culture supernatant of Gb03 strain shown strong algicidal activity on some of dinoflagellate been tested.
The culture filtrate also showed algicidal activity after being treated with different rang of temperature (4, 20, 40, 50, 70 and 100[degrees]C) for two hours.
There are many marine bacteria reported to have algicidal activity on various species of harmful algal blooms and red tide phytoplankton [12, 22].
Algicidal from marine bacteria play an important role by killing or inhibiting the growth of harmful algal bloom in coastal sea water where red tides occur frequently .
Related to the results of the stability of algicidal activity experiment, we came to know that is the algicidal compounds of Gb03 strain is not enzymatic, since the filtrate after incubated in water bath for two hours at 100[degrees]C, showed almost the same activity.
Therefore, our results showed that the algicidal bacterium Loktanella sp.