为了获得混合菌群利用木糖进行厌氧发酵产氢的最佳条件,通过批次实验,对中温(35℃)和高温(55℃)下混合菌群利用不同浓度木糖(10~50 g/L)厌氧发酵产氢系统进行了研究。结果表明,35℃下系统累积产氢量和最大氢气产率在底物浓度30 g/L时获得,乙醇和乙酸为主要产氢副产物,但继续提高底物浓度会造成系统VFAs的积累与p H下降,不利于木糖代谢产氢;而55℃下累积产氢量和氢气产率随底物浓度升高持续增长,乙醇为系统主要产氢副产物,VFAs累积量较少。高温下,虽然最大氢气产率和底物木糖降解量比35℃下的低,但有利于获得较为稳定的氢气产量,产氢系统在高底物浓度下也可保持较高的木糖降解率和较为稳定的p H,有利于木糖代谢产氢。
To obtain optimal conditions for anaerobic fermentation hydrogen from xylose by mixed culture,bio-hydrogen production from different concentrations of xylose( 10—50 g / L) at mesophilic( 35℃) and thermophilic temperatures( 55℃) by mixed culture fermentation was investigated in batch operation. The results showed that the maximum cumulative hydrogen volume and hydrogen yield were obtained with substrate concentration of 30 g / L in the system at 35℃,and hydrogen production by-products of the system mainly was ethanol,followed by acetate,however,the increase of substrate concentration resulted in accumulation of VFAs and decrease of p H,which was not conducive to hydrogen production by xylose metabolism. However,with the increase of substrate concentration,the cumulative hydrogen volume and hydrogen yield increased at 55℃,by-products of the system was mainly ethanol with less accumulation of VFAs. Although the maximum hydrogen yield at 55℃was lower than it at 35℃,it was conducive to obtain stable hydrogen output,hydrogen production system could maintain higher degradation efficiency of xylose and stable p H,which was conducive to hydrogen production at thermophilic temperature.