Production of Nano-sized Zeaxanthin-contained Particulates from Sea Water Cultivated Nannochloropsis Oculata Using Supercritical Fluids Extraction and Anti-solvent Crystallization

• Main Authors: Siang-En Hong, 洪祥恩
• Other Authors: Chieh-ming J. Chang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/05107972866263481475

碩士 === 國立中興大學 === 化學工程學系所 === 99 === This work investigated supercritical carbon dioxide (CO2) anti-solvent recrystallization of zeaxanthin-containing particulates from microalgal Nannochloropsis Oculata species. The extract of the algae containing 3.613 mg/g zeaxanthin using ultrasonic stirred acetone extraction subjected to column elution fractionation for increasing the amount of zeaxanhin in the fraction to 425.6 mg/g by weight with the recovery of 82.7 %. Supercritical anti-solvent (SAS) precipitation of the column fraction at 215 bar, 50 oC, 36 g/min of CO2 flow rate, 0.5 ml/min of feed solution containing, 1.5 mg/ml of feed concentration results in 659.3 mg/g of zeaxanthin in the precipitates. However, another SAS precipitation of acetone solution at the 2.0 mg/ml of feed concentration yields 479.0 mg/g of zeaxanthin. A three-factor center composited schemed response surface method by changing feed concentration, CO2 flow rate, and pressure designed for the SAS precipitation was carried out in finding total yield, purity, recovery and particle size of the precipitates. The highest purity is 841.7 mg/g of zeaxanthin with 85.3 % recovery, obtained at feeding concentration of 1.5 mg/ml, CO2 flow rate of 48.6 g/min and pressure of 135 bar. The decreasing pressure favored dispersible precipitates.The mean particle size of these non-uniform nano-sized tabular precipitates ranged from 103 to 327 nm.