title: Enhanced biotransformation of 2-phenylethanol with ethanol oxidation in a solid-liquid two-phase system by active dry yeast.
abstract: 2-Phenylethanol (2-PE) can be produced from L: -phenylalanine (L: -Phe) with the oxidation degradation of ethanol by active dry yeast. In this study, the catalysis effect of ethanol on biotransforming L: -Phe into 2-PE by yeast was evaluated and optimized. The results indicated that increasing ethanol concentration was beneficial for enhancing 2-PE concentration but lowered the 2-PE productivity. Initial ethanol concentration above 25 g/l could strongly inhibit the 2-PE production. To obtain 2-PE with desirable concentrations with an economical operation mode, three fed-batch biotransformation operation methods using ethanol or/and glucose were carried out in a solid-liquid two-phase system. When using ethanol alone with the initial concentration of 10 g/l, the total concentration and overall productivity of 2-PE were 7.6 g/l and 0.065 g l(-1) h(-1), respectively. Furthermore, an experiment with controlled glucose solely (higher than 2 g/l) was finished. In this case, phenylacetaldehyde (PA) was detected along with ethanol accumulation, suggesting that reaction of PA → 2-PE in Ehrlich pathway was inhibited. To further enhance 2-PE production by using glucose only, a novel operation strategy to simultaneously control rates of glucose glycolysis and ethanol oxidative degradation with the aid of ISPR techniques was developed. With this strategy, 2-PE concentration and yield based on glucose consumption reached a higher level of 14.8 g/l and 0.12 g-PE/g-glucose, respectively, and these are the highest values reported up to date with the fed-batch biotransformation operation mode.
authors: School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 120, Cao-Board Road, Shanghai 200235, China. rongshaofeng@163.com
authors: Shaofeng
authors: S
authors: Rong
authors: Baomei
authors: B
authors: Ding
authors: Xiaoli
authors: X
authors: Zhang
authors: Xuesong
authors: X
authors: Zheng
authors: Yifei
authors: Y
authors: Wang
mesh_terms: D001711:Biotransformation; D046508:Culture Techniques / Q000379:methods*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D010084:Oxidation-Reduction; D010626:Phenylethyl Alcohol / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D000431:Ethanol; D010626:Phenylethyl Alcohol