| Summary: | 碩士 === 國立高雄科技大學 === 化學工程與材料工程系 === 107 === The phycobiliproteins are mainly classified into R-phycoerythrin (R-PE), C-phycocyanin (C-PC) and allophycocyanin (APC), which can be applied to fluorescent probe, natural pigment and healthy foods. The traditional purification of phycobiliproteins is complicated and time consuming. The development of adsorption recovery program helps to simplify separation and purification steps. In view of this, this study developed an adsorbent capable of affinity to phycobiliproteins, and directly adsorbed C-PC and APC from the Spirulina platensis homogenate. In the study, the preparation method of polyethylenimine modified hydroxyapatite composites (HAp-PEI), the adsorption model of the HAp-PEI for C-PC and APC, and the condition for adsorbing of C-PC and APC from the Spirulina platensis homogenate by HAp-PEI. First, the eggshell was calcined, then dipotassium hydrogen phosphate is added to prepare the hydroxyapatite, and finally the TMS-PEI is added to modify the hydroxyapatite to obtain the polyethyleneimine modified hydroxyapatite composite form eggshell as the raw material. The surface morphology was observed by transmission electron microscopy (TEM). The X-ray diffraction analyzer (X-ray) was used to determine the successful preparation of the hydroxyapatite. The amino functionalized surface of HAp-PEI was confirmed by Fourier transform infrared spectrum (FTIR), thermogravimetry analyzer (TGA) and Zate potential analysis. Then, the adsorption experiment indicated that the adsorption capacity of HAp-PEI toward C-PC was highest at pH 5.0 acetic acid, the maximum adsorption capacity was 142.9 mg C-PC/g particles; and the best adsorption of APC in pH 6.0 acetic acid, the maximum adsorption capacity was 641.0 mg APC/g particles. Therefore, the results showed that the adsorption of C-PC and APC by HAp-PEI could be correlated by the pseudo-second-order kinetic model, indicates the adsorption mechanism is dominated by chemical adsorption and the adsorption behavior followed the Langmuir isotherm, indicating the adsorption mechanism by monolayer adsorption. The isoelectric point of phycobiliprotein is about 4.5-5.5. The potential of HAp-PEI is positive charge at pH 5.0 and pH 6.0. Therefore, the adsorption mechanism of HAp-PEI on C-PC and APC should be electrostatic interaction. In the application of adsorption recovery, HAp-PEI was added to the pH 6.0 Spirulina platensis homogenate to adsorb C-PC and APC, and then desorbed with pH 8 phosphate buffer solution. Even in the presence of impurities, the recovery rate of HA-PEI to C-PC was 31.3%, the purification factor was 3.8, the purity index was increased from 0.636 to 0.663. The recovery rate of HAP-PEI to APC was 38.6%, and the purification factor was 4.7, the purity index increased from 0.269 to 0.310. Therefore, HAp-PEI can achieve the purification effect on C-PC and APC, and compared with the purification multiple, HAp-PEI can be proved to have better adsorption selectivity to APC.
|
|---|
