earticle

영어

Microalgal oil could be considered as one of suitable feedstocks for the production of biodiesel (methyl/ethyl ester of fatty acids). In this study, effects of light intensity and nitrate concentration on the cell growth and fatty acids production of highly-CO2-tolerant microalga Chlorella sp. KR1 were investigated using bubble column photobioreactors. The CO2 concentration and gas flowrate were kept at 10% (v/v) and 0.5 L/min (1 vvm), respectively. With increasing light intensity from 22 to 89 μmol/m2/s at a nitrate concentration of 5 mM, final cell density increased almost linearly from 0.7 g/L to 4.3 g/L, and total intracellular fatty acids content also increased significantly from 126.6 to 361.7 mg/g cell. When nitrate concentration was varied in the range of 1 – 20 mM at a light intensity of 70 μmol/m2/s, optimal cell growth (3.3 –3.4 g/L) was observed at 5 - 10 mM nitrate. At higher nitrate concentration of 20 mM, cell density decreased slightly to 3.0 g/L and, at lower concentration of 1 mM, a relatively low cell density of 1.2 g/L was observed. Intracellular fatty acids content showed a decreasing trend with increasing nitrate concentration. Maximal fatty acids production (1492.7 mg/L) was observed at light intensity of 89 mmol/m2/s and nitrate concentration of 5 mM, and major fatty acids were palmitic acid (27%, w/w), linoleic acid (24%), and oleic acid (23%). This study shows that light intensity and
nitrate concentration are important factors for the production of fatty acids using Chlorella sp. KR-1.