Two-stage cultivation system을 이용한 미세조류 성장 최적화 및 스트레스 조건별 고부가가치 물질의 축적 촉진

Abstract

Astaxanthin is famous as a super antioxidant, and is a substance with much higher antioxidant power compared to antioxidants such as various vitamins. Based on these useful properties, astaxanthin is being applied to various industries such as food, cosmetics, and pharmaceuticals. In the case of synthetic astaxanthin, there are reports that there is a risk that it may contain traces of residual solvents and chemical reagents, and it is unclear what effect it will have on the human body if consumed over a long period of time. Therefore, the demand for natural astaxanthin is rapidly increasing. In the case of microalgae, it is a good raw material with fewer by-products and higher production of astaxanthin compared to other raw materials. Microalgae can be easily cultivated anywhere as long as the simple conditions of water, light, and carbon dioxide are met. Among microalgae, Haematococcus pluvialis is a good raw material with the highest content for the production of astaxanthin, but it has inherent disadvantages such as low growth rate. On the other hand, Chlorella zofingiensis is known to be easier to cultivate, including its high growth rate. In this study, we optimized culture parameters for productivity of Chlorella zofingiensis and analyzed the accumulation of astaxanthin under stress conditions. Microalgae were applied to a two-stage cultivation system, and the first stage was optimized by controlling the N source and P source in the culture medium to maximize biomass production. In the second stage, a stress environment was created to maximize the accumulation of astaxanthin, and the amount of astaxanthin accumulated was observed using wavelength and light intensity using LED and salt stress. In the first stage, the maximum biomass of 1.88 g dcw/L was produced at an N source concentration of 1.5 g/L, P source 20 mg/L, and fluorescent light intensity of 50 µmol/m²/s. In the second stage, the maximum amount of astaxanthin was produced at 2.21 mg/L under the conditions of LED green wavelength (520 nm) light intensity of 200 µmol/m²/s and N source. Compared to other conditions, the production of astaxanthin using Chlorella zofingiensis is also judged to be higher in a stress environment because the production of biomass is high under conditions where N source is sufficient.