木质纤维素水解液副产物对东方伊萨酵母乙醇发酵的影响

Effect of byproducts in lignocellulose hydrolysates on ethanol fermentation by Issatchenkia orientalis

摘要:

为了客观评判耐高温东方伊萨酵母HN-1利用木质纤维素水解液生产燃料乙醇的潜力，本文采用单因素试验和响应面中心组合试验研究了木质纤维素水解液有毒副产物甲酸钠 (1.0?5.0 g/L)、乙酸钠 (2.5?8.0 g/L)、糠醛 (0.2?2.0 g/L)、5-羟甲基糠醛 (0.1?1.0 g/L) 和香草醛 (0.5?2.0 g/L) 对其乙醇发酵的影响。结果表明，木质纤维素水解液有毒副产物对东方伊萨酵母HN-1乙醇发酵的影响较小，除添加2 g/L香草醛或添加1 g/L 5-羟甲基糠醛可使乙醇产量分别降低20.38%和11.2%外，其他抑制物的添加对乙醇的生成未有显著影响。但是，当副产物浓度较高时，可以显著抑制菌体生长，添加1?5 g/L甲酸钠、2.5?8.0 g/L乙酸钠、0.4?2 g/L糠醛或0.5?2 g/L香草醛，发酵36 h时菌体细胞干重分别较对照下降了25.04%?37.02%、28.83%?43.82%、20.06%?37.60%和26.39%?52.64%。中心组合试验结果表明各抑制物交互作用对乙醇的生成影响不显著。该研究表明木质纤维素水解液副产物对东方伊萨酵母HN-1乙醇发酵的影响较小，适合用于纤维乙醇发酵。

Abstract:

Byproducts in lignocellulose hydrolysates, namely sodium formate (1 to 5 g/L), sodium acetic (2.5 to 8.0 g/L), furfural (0.2–2 g/L), 5-hydroxymethylfurfural (5-HMF, 1 to 1.0 g/L ) or vanillin (0.5 to 2 g/L) were used to evaluate their effects on ethanol fermentation by Issatchenkia orientalis HN-1 using single factor test and the response surface?central composite experiment. Results showed that most of the byproducts had no obvious inhibition on the production of ethanol, except for the addition of 2 g/L vanillin or 1 g/L of 5-HMF, which reduced the ethanol production by 20.38% and 11.2%, respectively. However, high concentration of some byproducts in lignocellulose hydrolysates, such as sodium formate (1 to 5 g/L), sodium acetic (2.5 to 8.0 g/L), furfural (0.2 to 2 g/L) and vanillin (0.5 to 2 g/L) inhibited the growth of I. orientalis HN-1 significantly. Compared with the control, the dry cell weight of I. orientalis HN-1 decreased by 25.04% to 37.02%, 28.83% to 43.82%, 20.06% to 37.60% and 26.39% to 52.64%, respectively, when the above components were added into the fermentation broth and the fermentation lasted for 36 h. No significant interaction effect of the various inhibitors (sodium formate, sodium acetic, furfural and vanillin) except for vanillin single factor on the ethanol production was observed based on the central composite experiments. The concentrations of byproducts in most lignocellulose hydrolysates were below the initial inhibition concentration on ethanol production by Issatchenkia orientalis HN-1, which indicated that Issatchenkia orientalis HN-1 can be used for ethanol production from lignocellulose hydrolysates.