2-苯乙醇对酿酒酵母生理生化特性影响

【目的】研究在不同浓度2-苯乙醇作用下,酵母生理生化特性的变化规律,为优化2-苯乙醇生物合成过程提供重要依据。【方法】透射电镜观察细胞形态;流式细胞术检测细胞膜渗透性、胞内ROS浓度、线粒体膜电位;实时荧光定量PCR检测关键酶基因表达。【结果】随着2-苯乙醇浓度增加(从0到4.0 g/L),酵母细胞分解代谢能力、细胞膜渗透性及aro10基因表达量逐渐降低;线粒体膜电位逐渐增加;胞内ROS浓度先增加后减少。当2-苯乙醇浓度从2.4 g/L增加到3.0 g/L,酵母的分解代谢能力、细胞膜渗透性、aro10基因表达水平等生理生化特性都发生较为显著的变化。【结论】产物原位转移过程中水相2-苯乙醇浓度可考虑控制在2.4 3.0 g/L。

Effects of 2-phenylethanol on physiological and biochemical characteristics of Saccharomyces cerevisiae

Objective] To provide useful basis for enhancing the biosynthesis of 2-phenylethanol(PEA),we studied the variation of physiological and biochemical characteristics of Saccharomyces cerevisiae sp.strain R-UV3 treated on varied concentrations of PEA.Methods] Morphological observation was performed by a transmission electron microscope.Membrane permeabilization,intracellular reactive oxygen species(ROS) and mitochondrial membrane potential after staining with propidium iodide,dihydroethidium and rhodamine 123 respectively were investigated at the single-cell level with flow cytometry.The expression of aro10 gene was determined by real-time fluorescence quantitative PCR.Results] With the increasing PEA concentration(0-4.0 g/L),the membrane permeabilization,glycometabolism and expression of aro10 gene in the yeast cell decreased and mitochondrial membrane potential increased.ROS increased when PEA concentration was below 3.0 g/L and decreased when PEA concentration was beyond 3.0 g/L.The physiological and biochemical characteristics of the yeast,such as membrane permeabilization,glycometabolism and expression of aro10 gene,varied notably as PEA concentration increased from 2.4 g/L to 3.0 g/L.Conclusions] The aqueous PEA concentration should be controlled at 2.4-3.0 g/L when in situ PEA removal technology was performed.