Lignin degradation products are main inhibitors that restrain the ethanol production by fermentation of lignocellulosic hydrolysate. The objective of the present study was to clarify the inhibition of lignin degradation products on Saccharomyces cerevisiae. The toxicity of lignin preparation and phenolic compounds such as vanilla aldehyde,lilac alcohol,and p⁃hydroxy benzaldehyde was measured by culturing Saccharomyces cerevisiae CGMCC 2�1429. Then,the change of cell membrane permeability was evaluated by the concentration of fructose⁃1,6⁃diphosphate ( FDP ) . Results show that the 50% lethal concentration ( LC50 ) of lignin preparation, vanilla aldehyde, lilac alcohol, and p⁃hydroxy benzaldehyde was 10�96, 5�37,6�17 and 7�08 g/L,respectively. All the phenolic compounds acted synergistically on yeast cells. Fructose⁃1,6⁃diphosphate ( FDP ) concentration in culture medium increased linearly with increasing logarithmic concentration of each phenolic compound. When the concentration of each phenolic compound increased from 1�58 g/L to 10�00 g/L,FDP concentration increased from 49�7 mg/L to 134�4 mg/L. The toxicity of lignin degradation products on Saccharomyces cerevisiae closely related to the change of cell membrane permeability.%木质素降解物是影响木质纤维素水解液乙醇发酵效率的主要原因之一。为探明木质素降解物对酿酒酵母的毒性，通过酿酒酵母（ Saccharomyces cerevisiae） CGMCC 2�1429的液体培养，测定木质素制剂及酚类化合物（香草醛、紫丁香醇和对羟基苯甲醛）对细胞的毒性，同时分析酚类化合物的联合作用类型，最后以果糖1，6二磷酸（ FDP ）为指标来分析木质素制剂及酚类化合物酵母细胞膜通透性的变化。结果表明：木质素制剂、紫丁香醇、对羟基苯甲醛和香草醛的半致死质量浓度分别为10�96、5�37、6�17和7�08 g／L。随着各酚类化合物浓度和种类的增加，它们对细胞的毒性随之增加，呈正协同作用。在培养液中，FDP浓度随各酚类化合物浓度的增加呈线性增加，当各酚类化合物的质量浓度从1�58 g／L增加到10�00 g／L时，FDP质量浓度从49�7 mg／L增加到134�4 mg／L。木质素降解物对酿酒酵母的毒性作用与细胞膜通透性的改变密切相关。
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