Isolation, Identification and Growth Optimization of Microalgae Derived from Soft Coral Dendronephthya sp.

Despite its beauty in shape and color, soft coral Dendronephthya sp. is less interesting commercially as an ornamental coral commodity due to its low chances of survival in artificial habitats. Unlike other corals, this species is azooxhantellae, and thus, it depends on external feeding. The aim of this research is to isolate, identify, and cultivate the microalgae derived from Dendronephthya sp. The microalgae was isolated from digestive tract, followed by genomic DNA isolation and Polymerase Chain Reaction. The algae cultivation was conducted using the nitrogen sources as proven treatment. Five species of microalgae (Amphora sp., Navicula salinicola, Meyerella planktonica, Nannochloris sp., and Nitzschia inconspicua) were successfully isolated. The highest biomass of Amphora sp. was obtained when ammonium was added as nitrogen source. Meanwhile, the highest biomass of N. inconspicua was obtained through the addition of nitrate. Finally, the highest biomass of N. salinicola was acquired when a combination of ammonium and nitrate was used.