Production of 2-Phenylethyl alcohol and 2-Phenylethyl acetate by immobilization cultures of Pichia fermentans L-5

• Main Authors: Chien-Yu Lee, 李建育
• Other Authors: Jyh-Shyong Chang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/xu4rgh

碩士 === 大同大學 === 化學工程學系(所) === 95 === Pichia fermentans L-5 was entrapped by drop-wise addition of an aqueous mixture of sodium alginate to a hardening solution of a Ca2+ salt. Effects of immobilization conditions such as alginate concentration, CaCl2 concentration, ratio by weight of cell to alginate (C/A) and bead size on the average loss of the immobilized cell and the residual cell immobilized in the bead over five cultivation days were investigated. Six experiments located by the uniform design (UD) method were carried out to find the optimized immobilization condition (alginate concentration 4.4 (w/v), CaCl2 concentration 2.0 (w/v), cell concentration 42 (A600), bead size 1.5mm). Adopting the same culture conditions (100mL culturing medium in a 250mL Erlenmeyer flask, shaking at 200rpm at 30 for 24h per run) and the obtained optimized immobilization condition, production of 2-phenylethanol and 2-phenylethyl acetate by the immobilized and free Pichia fermentans L-5 were carried out. It was found that the immobilized cell can give 88% (246/280(mg/L)) and 63% (220/350(mg/L)) production efficiency of 2-phenylethanol and 2-phenylethyl acetate respectively with respect to the free cells cultivation. Although the immobilized cell cultivation cannot maintain the same production efficiency as the free cells cultivation, the used free cells cannot generate any products in the second run (another 24 h) because the free cells may be poisoned by their products. On the other hand, the same immobilized cells can be cultivated for 5 runs continuously to produce 2-phenylethanol (242~67mg/L) and 2-phenylethyl acetate (226~167mg/L). The cultivation process using the immobilized cells can be improved by two sets of the immobilized cell beads. When the first set of the immobilized cell beads were cultivated, the second set of the immobilized cell beads were maintained in the preculturing medium containing 5% glucose and 0.25% yeast extract. By this operating mode (5 runs for each set in 10 days), the productions of 2-phenylethanol and 2-phenylethyl acetate were ranged from 267 to 206mg/L and 219 to 190mg/L respectively.