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以棕榈残渣(Empty fruit bunch,EFB)为原料,通过预处理、酶解、发酵等过程制备纤维乙醇。首先对比了碱、碱/过氧化氢等预处理条件对棕榈残渣组成及酶解的影响,结果表明稀碱预处理效果较好。适宜的稀碱预处理条件为:NaOH浓度为1%,固液比为1∶10,在40℃浸泡24 h后于121℃下保温30 min,在该条件下,EFB的固体回收率为74.09%,纤维素、半纤维素和木质素的含量分别为44.08%、25.74%和13.89%。对该条件下预处理后的固体样品,以底物浓度5%、酶载量30 FPU/g底物酶解72 h,纤维素和半纤维素的酶解率分别达到84.44%和89.28%。进一步考察了酶载量和底物浓度对酶解的影响以及乙醇批式同步糖化发酵,当酶载量为30 FPU/g底物,底物浓度由5%增加至25%时,利用酿酒酵母Saccharomyces cerevisiae(接种量为5%,V/V)发酵72 h后乙醇的浓度分别为9.76 g/L和35.25 g/L,可分别达到理论得率的79.09%和56.96%。
Using empty fruit bunch (EFB) as raw material, the fiber ethanol was prepared by pretreatment, enzymolysis and fermentation. First of all, the effects of pretreatment conditions such as alkali, alkali / hydrogen peroxide on the composition and enzymatic hydrolysis of palm residues were compared. The results showed that the pretreatment with dilute alkali was better. The optimal conditions for dilute alkali pretreatment were as follows: the concentration of NaOH was 1%, the solid-liquid ratio was 1:10, soaked at 40 ℃ for 24 h and then incubated at 121 ℃ for 30 min. The recovery of EFB was 74.09 %, The contents of cellulose, hemicellulose and lignin are 44.08%, 25.74% and 13.89% respectively. Under these conditions, the enzymatic hydrolysis rate of cellulose and hemicellulose reached 84.44% and 89.28% respectively under the conditions of 5% substrate concentration and enzyme loading of 30 FPU / g substrate for 72 h. The effects of enzyme loading and substrate concentration on enzymolysis and ethanol batch-wise simultaneous saccharification and fermentation were also investigated. When the enzyme loading was 30 FPU / g and the substrate concentration was increased from 5% to 25% After 72 h of fermentation, the ethanol concentrations of Saccharomyces cerevisiae (inoculum size 5%, V / V) were 9.76 g / L and 35.25 g / L, respectively, which reached 79.09% and 56.96% of theoretical yield, respectively.