“酒精沼气双发酵耦联工艺”中硫化物对酒精发酵的影响

Effect of Sulfide on Ethanol Fermentation in the “Ethanol Methane Coupled Fermentations” Process

"酒精沼气双发酵耦联工艺"中硫化物会对酒精发酵产生抑制,不利于工艺的稳定运行。与对照相比,pH 4.0,24 mmol/L的硫化物使酒精发酵时间从48 h延长至318 h,酒精产量由90.73 g/L下降至82.28 g/L,酵母数量由3.78×108/mL下降至2.20×108/mL,甘油产量由6.99 g/L上升至11.02 g/L。甘油产量上升是硫化物存在时酒精产量下降的原因之一。硫化物对酒精发酵的抑制性随添加时间的推迟而减弱,这是因为在酒精发酵过程中,硫化物会以H2S的形式随着CO2一起从发酵液逸出。pH 4.0时,硫化物对酒精发酵的临界抑制浓度为1.2 mmol/L。

Ethanol fermentation could be inhibited by sulfide, which is harmful to the process of ethanol methane coupled fermentations. Compared to the control, at pH 4.0 and with 24 mmol/L sulfide existed, ethanol fermentation time was prolonged from 48 to 318 h, ethanol concentration was decreased from 90.73 to 82.28 g/L, yeast cell number was declined from 3.78 × 10^8 to 2.20 × 10^8 cell/mL, and glycerol concentration was increased from 6.99 to 11.02 g/L. Increased glycerol production could contribute to the decreased ethanol production when sulfide existed. Inhibition of sulfide to ethanol fermentation was weakened as delay of addition, because sulfide could escape from the fermentation broth with CO2 as the form of H2S. At pH 4.0, critical inhibition concentration of sulfide to ethanol fermentation was 1.2 mmol/L, cassava, fuel ethanol, sulfate, sulfide, critical inhibition concentration