신규 저가배지를 이용한 Chaetoceros속 3종 미세조류의 최적 배양 및 상업적 이용

Abstract

Optimal mixotrophic cultivation conditions of Chaetoceros species to obtain enhanced biomass and lipid productivities were investigated. The low-cost medium for cultivation of Chaetoceros species, which could be used as a food for shell-fish, were prepared by mixing f/2 medium with mud or/and food waste extract. Compared with Chaetoceros strains cultivated in a f/2 medium (used as a control), the biomass and lipid productivities of those cultivated in a f/2 medium containing mud extract increased two-fold. The biomass productivity increased three-fold when the cells were cultivated in a f/2 medium containing food waste extract, whereas lipid productivity decreased significantly. Interestingly, the biomass and lipid productivities of Chaetoceros strains increased ten times when they were cultivated in a medium containing mud and food waste (although the mixture ratios are a little bit different depending on microalgal strains). It was found that mud extract contains high concentrations of microelements, humic and fulvic acids, whereas food waste contains high concentrations of nitrogen, phosphorous and organic compounds. Fatty acid analysis was performed using gas chromatography to determine the possibility of lipid conversion to bio-diesel. After cell disruption, total lipid contents were determined and direct trans-esterification reaction was carried out. Concomitantly about 35% (w/w) lipid content was obtained after cell disruption by treatment with autoclave and microwave. In addition, the highest concentration of fatty acid methylester (FAME) was observed when 10% (v/v) sulfuric acid was used as a catalyst at 100 ℃ for 120 minutes.