盐类对树干毕赤酵母乙醇发酵及其细胞膜流动性的影响

摘要

以树干毕赤酵母为发酵菌株,研究氯化盐类和硫酸盐类对其己糖戊糖共发酵影响,并采用荧光偏振法测定盐类对酵母细胞膜流动性的影响. 研究结果表明,盐类对树干毕赤酵母发酵有着明显的抑制作用;当氯化盐的浓度达到0. 5 mol/L、发酵24 h时,NaCl对乙醇发酵的抑制作用最为明显,与未添加氯化盐相比,糖利用率、乙醇浓度以及乙醇得率分别下降了52. 00 %、65. 10 %、22. 50 %,盐离子对树干毕赤酵母发酵的抑制作用Na+ >NH4+ >K+.硫酸盐中的阳离子浓度是氯化盐的2倍,但抑制作用没有显著不同,所以Cl-对树干毕赤酵母的乙醇发酵抑制作用要大于SO2-4 ;高盐浓度下细胞膜的流动性更高,且不同盐离子对细胞膜的流动性影响也不同,NH4+对细胞膜的流动性影响最大,细胞膜流动性的增加可能是增加细胞对压力的耐受性,降低对细胞的损失.%The effects of chlorides and sulfates on co-fermentation of glucose and xylose by Pichia stipitis NLP31were investigated, and fluorescence polarization was used as to determine the effect of salts on membrane fluidity. The results showed that salt concentration had a significant negative impact on the fermentation performance of yeast. When the concentration of salt was 0. 5 mol/L, after 24 h, the inhibition effect of NaCl was the most. The sugar utilization ratio, ethanol concentration and ethanol yield decreased by 52. 00%, 65. 10% and 22. 50%, respectively, compared to that of the control. The inhibition effect of chlorides was Na+ >NH4+ >K+. Al-though cation concentrations in the sulfates were twice in the chlorides, the inhibition effect had not significant difference. So the inhi-bition effect of Cl- on ethanol fermentation by P. stipitis was more significant than that of SO2-4 . The membrane fluidity of yeast in high concentration of salts became higher, and the different salt ions had different effects on cell membrane fluidity. NH4+ showed the grea-test impact on cell membrane fluidity. Increased membrane fluidity could increase cellular resistance to stress, and decrease cell loss.