Study On The Production Of β-phenylethanol By Microbial Method

β-phenylethanol(β-PE) is a higher aromatic alcohol with a rose-like odour. The fragrance of the rose is highly popular and desired, makingβ-PE the most-used fragrance chemical in perfume and cosmetics. It is also used in flavor compositions for food. Most of the world's annual production of several thousand tons is synthesized by chemical means but, due to increasing demand for natural flavors, alternative production methods are being sought. Harnessing the Ehrlich pathway of yeasts by bioconversion of L-phenylalanine toβ-PE could be an good option.In this work, systematic studies were carried out on the screening of yeast strains which can transform L-phenylalanine toβ-PE; determination, isolation, purification, identification, quantification method ofβ-PE.Kluyveromyces marxious AS.2.1440 was screened from the microorganism strains preserved by our laboratory. This strain can transform 7.0g/L L-phenylalanine to 0.920g/Lβ-PE. According to the chemical structures of L-phenylalanine andβ-phenylethanol, we established some methods for the separation and determination of them: TLC method for the determination ofβ-PE; ninhydrin reaction method for the determination of L-phenylalanine; RP-HPLC method for the separation and determination of L-phenylalanine andβ-phenylethanol, this method was accurate, sensitive and reliable.The conditions of liquid fermentation ofβ-PE were studied. It showed that the effect of single factors, such as carbon source, nitrogen source, growth factors and inorganic salts on the production ofβ-PE. Through orthogonal test, the optimum medium composition had been obtained. It was 35g/L sucrose, 6g/L L-phenylalanine, 0.4g/L KH2PO4 and 1.8g/L YNB. The optimum shaking culture condition was as follows: 24 hours strain age, 6% inoculation quantity, initial medium pH=5.48, 50 mL medium in 250mL shaking flask, 28℃, 220r/min shaking speed, 48 hours incubation. Under this condition, productivity ofβ-PE was 1.4097g/L, while with the initial medium composition, the result was 0.920g/L.For isolation ofβ-PE, the adsorption and desorption performance of 13 types of macroporous adsorbent resins were studied and compared. H103 resin was selected for its high adsorption and desorption capacity. The effect of concentration, pH and flow rate of the infusion on the adsorption of H103 resin were studied with dynamic adsorption experiment. The extract solution at a concentration of 1.3g/L, pH of 5.48, flow rate of 3BV/h were the optimal condition .When using 6BV 95% ethanol as...