顶空CO_2对有机物厌氧发酵产挥发性脂肪酸的影响

Effects of CO_2 in headspace of bioreactor on volatile fatty acids generation from organic matters by anaerobic fermentation

研究了不同顶空CO2浓度对有机物厌氧发酵体系中底物转化速率、挥发性脂肪酸(VFA)产率及微生物相变化的影响.结果表明,顶空低浓度CO2有助于葡萄糖底物转化,在16h转化率达到93%以上,顶空高浓度CO2和对照组在20h时转化率分别为88.3%、87.6%.顶空高浓度CO2有助于乙酸积累,乙酸产率达8.2mmol/gCOD,分别是对照组和低浓度CO2组的1.52倍和1.87倍.顶空CO2浓度与同型产乙酸菌数量正相关,顶空低浓度CO2组fhs基因拷贝数为9.83×106/mL,高浓度CO2组fhs基因拷贝数为5.32×108/mL,对照组fhs基因拷贝数为6.97×107/mL.提高顶空CO2浓度有利于在混和培养环境中富集同型产乙酸菌.

The effects of CO2 concentrations in headspace of anaerobic fermentation system on the volatile fatty acids（VFA） generation,substrate degradation and homoacetogen change were investigated.Low concentration of headspace CO2 was helpful for the substrate degradation.The substrate degradation efficiency of low CO2,high CO2 and control are over 93% at 16h,87.6% and 88.3% at 20h,respectively.The high CO2 concentration improved the acetate accumulation with the conversion yield at 8.2 mmol/gCOD at the end of fermentation,which was 1.52 and 1.87 folds of the control and low CO2 reactors,respectively.There was a positive relationship between CO2 concentration and the quantity of homoacetogen.The fhs gene copy numbers were 9.83×106/mL,5.32×108/mL,6.97×107/mL in the low CO2,high CO2 and the control reactors,respectively.The homoacetogen could be enriched from a mixed culture by a high CO2 concentration in the headspace.