Liquefaction of lignocellulose at high-solids concentrations
Liquefaction of lignocellulose at high-solids concentrations
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DOI：
10.1002/bit.21115
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发表时间：
2007-04-01
影响因子：
3.8
通讯作者：
Felby, Claus
中科院分区：
文献类型：
--
作者：
Jorgensen, Henning;Vibe-Pedersen, Jakob;Felby, Claus
为提高木质纤维素制乙醇工艺的工艺经济性，开发了高固相浓度下的酶液化糖化反应器系统。这项技术基于自由落体混合，采用水平放置的转鼓和水平旋转轴，安装有搅拌器用于混合。在初始干物质含量高达40%(w/w)的情况下，对处理后的麦草进行了酶液化和糖化试验。在不到10h的时间内，材料的结构从完整的稻草颗粒(长度为1-5 cm)转变为可泵送的糊状/液体。试验表明，混合速度在3.3-11.5rpm范围内对24 h后的葡萄糖转化率和48 h后的乙醇产量没有显著影响，因此可以采用低功率输入进行混合。液化糖化96h，酶载量为7FPU/g DM和40%DM，葡萄糖浓度为86g/kg。在初始干物质含量为2%-40%(w/w)时进行的试验表明，随着干物质的增加，纤维素和半纤维素的转化率几乎呈线性下降。同时进行糖化和发酵的实验也表明，随着初始DM的增加，乙醇产量下降。酿酒酵母能发酵40%DM的水解液。35%(w/w)DM的乙醇浓度最高，为48g/kg。利用该反应器系统对生物质进行液化，使发酵液中含有10%(w/w)乙醇的可能性成为可能，未来木质纤维素将用于乙醇工厂。
To improve process economics of the lignocellulose to ethanol process a reactor system for enzymatic liquefaction and saccharification at high-solids concentrations was developed. The technology is based on free fall mixing employing a horizontally placed drum with a horizontal rotating shaft mounted with paddlers for mixing. Enzymatic liquefaction and saccharification of pretreated wheat straw was tested with up to 40% (w/w) initial DM. In less than 10 h, the structure of the material was changed from intact straw particles (length 1-5 cm) into a paste/ liquid that could be pumped. Tests revealed no significant effect of mixing speed in the range 3.3-11.5 rpm on the glucose conversion after 24 h and ethanol yield after subsequent fermentation for 48 h. Low-power inputs for mixing are therefore possible. Liquefaction and saccharification for 96 h using an enzyme loading of 7 FPU/g.DM and 40% DM resulted in a glucose concentration of 86 g/kg. Experiments conducted at 2%-40% (w/w) initial DM revealed that cellulose and hemicellulose conversion decreased almost linearly with increasing DM. Performing the experiments as simultaneous saccharification and fermentation also revealed a decrease in ethanol yield at increasing initial DM. Saccharomyces cerevisiae was capable of fermenting hydrolysates up to 40% DM. The highest ethanol concentration, 48 g/kg, was obtained using 35% (w/w) DM. Liquefaction of biomass with this reactor system unlocks the possibility of 10% (w/w) ethanol in the fermentation broth in future lignocellulose to ethanol plants.