纤维素降解产物对Kluyveromyces marxianus 1727共发酵葡萄糖和木糖的影响

研究纤维素酸水解产生的4种副产物乙酸、甲酸、糠醛、5-羟甲基糠醛及发酵产物乙醇对Kluyveromyces marxianus 1727共发酵葡萄糖和木糖的影响。结果表明:5.0 g/L乙酸和1.0 g/L甲酸对葡萄糖和木糖共发酵具有明显的抑制作用;1.0 g/L糠醛和5-羟甲基糠醛基本不影响K.marxianus 1727发酵葡萄糖,且能够被K.marxianus1727转化为毒性相对较低的物质。由于5-羟甲基糠醛的转化速率慢,对K.marxianus 1727发酵木糖的抑制程度大于糠醛。乙醇对K.marxianus 1727发酵木糖具有抑制作用,当乙醇质量浓度大于20 g/L时,生物量及木糖利用率约是对照的44%和70%。

Effects of lignocellulose using glucose and degradation products on xylose by Kluyveromyces ethanol fermentations marxianus 1727

The inhibitory effects of four lignocellulose degradation products and ethanol on glucose and xylose fermentation by Kluyveromyces marxianus 1727 were studied in batch cultures. Toxic compounds were added in variable concentrations, and subsequent inhibitions on growth and ethanol production were tested. The acetic acid and the formic acid were shown to be strong inhibitors of both glucose and xylose fermentation when they were added to the culture media at concentrations of 5.0 g/L and 1.0 g/L, respectively. Furfural and 5-hydroxylmethyl furfural at a concentration of 1 g/L did not affect glucose fermentation, and could be changed into relatively low toxic substances. The inhibition of 5-hydroxylmethyl furfural was serious on xylose fermentation than furfural due to the transformation of the 5-hydroxylmethyl slower than that of furfural. Etha- nol was also shown to be strong inhibitors of xylose fermentation, when the ethanol concentration was more than 20 g/L, biomass and xylose transformation efficiencies were 44% and 70% of the control.