온도 차이에 따른 Nannochloropsis oceanica (Eustigmatophyceae)의 성장과 eicosapentaenoic acid (EPA) 함량 변화

Abstract

한국 연안에서 분리한 Nannochloropsis oceanica는 5~30°C의 폭넓은 온도 범위에서 성장하였다. 25°C 조건에서 최대세포밀도가 관찰되었지만, 20°C 조건에서는 86.2 mg L-1로 가장 높은 바이오매스 생산량을 보였다. 지방산의 경우, 5°C에서 총 지방산 함량(73.0 mg g-1)과 EPA 함량(16.3 mg g-1)이 가장 높았고, 지방산의 구성도 가장 다양하게 나타났다. 이러한 결과는 한국 연안에서 확보한 N. oceanica가 저온에서 높은 농도의 EPA를 효율적으로 합성하고 생산할 수 있다는 것을 나타낸다.

Nannochloropsis oceanica has been recognized as a valuable source of eicosapentaenoic acid (EPA) for nutraceutical applications. In this study, the effects of temperature on the growth and fatty acid production of N. oceanica were investigated to determine the optimal conditions for maximizing both growth and EPA production. The growth responses of N. oceanica exhibited a wide temperature range of 5-30°C, with the maximum cell density at 25°C(35.9×105 cells mL-1 ). Biomass production, as measured by dry weight in N. oceanica culture, was the highest at 20°C(86.2mg L-1 ). In N. oceanica cultures exposed to relatively low temperatures (5-10°C), cells did not grow significantly; however, the proportion of polyunsaturated fatty acids including EPA(22.3, 26.0% of total fatty acid), was significantly high. These results indicate that the optimal temperature conditions for promoting growth and EPA accumulation of N. oceanica are different. Based on these results, a temperature-dependent two-stage cultivation strategy was proposed to optimize both biomass and EPA production in N. oceanica cultures, which included an initial phase at 20°C to achieve high biomass, followed by a second phase at 5-10°C to maximize EPA accumulation.