Leptolyngbya is one of the genera of Cyanobacteria (prokaryotic microalgae) which are often found in the hot spring area. These microalgae are known to have potential as a biofuels source. In order to utilize microalgae, it is necessary to make efforts to produce microalgae biomass in large quantities. Biomass production depends on many environmental factors, one of which is the medium. The use of appropriate media and cheaply be one option, since biomass must be produced in large scale. Therefore, research on variations in the concentration of NPK fertilizer medium against the growth of Leptolyngbya HS-16 compared to Bold Basal Medium (BBM) was carried out. NPK fertilizer medium (nitrogen/N, phosphorus/P and potassium/K) is an inexpensive microalgae growth medium. Leptolyngbya HS-16 or Leptolyngbia with strain code of HS-16 is a Leptolyngbia strain isolated from a habitat in the hot springs of Mount Pancar Crater in Indonesia. The purpose of the study was to determine the effect of NPK medium concentration on the biomass weight of Leptolyngbya HS-16. The medium used in the study was BBM as the control medium, and NPK media with various concentrations of 80 ppm, 160 ppm, and 240 ppm as the treatment medium. In addition, the study aimed to determine the appropriate concentration of NPK medium to produce high biomass weight, supported by high lipid content. The results showed that Leptolyngbya HS-16 grew better in NPK medium with a concentration of 80 ppm compared to other concentrations. This can be seen from the results of the average biomass produced at peak time of 3.008 mg. L-1 and the log length of the Leptolyngbya HS-16. The lipid content was produced in the 80 ppm NPK medium was 45%.
Keywords: Leptolyngbya; Cyanobacteria; Biomass weight; Lipid content; Biofuel