| Summary: | 碩士 === 大同大學 === 生物工程研究所 === 88 === The optimal composition of medium, 39 g/l glucose and 12.6 g/l, to produce maximum cell mass of Pihica fermentans L-5 was obtained with response surface methodology. Factors affecting bioconversion of phenylalanine to 2-phenylethyl acetate by Pihica fermentans L-5 cultivated at 30℃and 200 rpm were also investigated. The cells harvested from mid-exponential growth phase （12-hr cultivation） produced higher concentrations of 2-phenylethyl acetate. The optimum cell concentrations for production of higher concentration of 2-phenylethyl acetate was ranged from 2.4 to 4.8 c.d.w. g/l. The optimal concentration of glucose and phenylalanine for production higher concentration of 2-phenylethyl acetate were 27 g/l and 900 mg/l, respectively. The initial pH of medium, ranged from 3 to 10, showed no significant difference in 2-phenylethyl acetate production. Increase in the aeration of the medium resulted in the enhancement of production of 2-phenylethyl acetate. When cultivation temperature was at 37.5℃, the maximum productivity of 2-phenylethyl acetate 70 mg l-1h-1, was found after 6 hr of cultivation. The maximum production of 2-phenylethyl acetate 474 mg/l , was obtained after 8 hr of cultivation at 37.5℃. An optimum composition of conversion medium, i.e. 765 mg/l phenylalanine and 20.4 g/l glucose, was obtained with response surface methodology under optimum operation condition. The theoretical value of 2-phenylethyl acetate was 467 mg/l. The experimental values of 2-phenylethyl acetate produced by Pihica fermentans L-5 were 484 479 and 469 mg/l.
|
|---|
