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作 者 ：徐红;徐勇;勇强;余世袁

期 刊 ：林业科学 2012年 48卷 11期 页码：92-97

关键词：红柳；蒸汽爆破预处理；反应强度；纤维素酶水解；

Keywords:Tamarix ramosissima, steam explosion pretreatment, reaction intensity, cellulose enzymatic hydrolysis,

摘 要 ：

以红柳为材料研究蒸汽爆破预处理强度系数lgR对木质组分和纤维素酶水解性能的影响。结果表明: 蒸汽爆破处理对红柳中纤维素和木质素含量的影响并不显著,但是它可以有效破坏红柳的天然物理结构,并且导致大部分半纤维素(木聚糖)产生自水解反应生成单糖和低聚糖溶出,同时产生乙酸、甲酸和糠醛等小分子降解产物。基于纤维素回收率和纤维素酶水解得率分析,在蒸汽爆破强度系数达到4.239时(爆破温度210℃和保温时间10 min)对红柳的预处理效果最佳,汽爆物料中纤维素的含量可达到 52.4%,残余木聚糖含量仅为2.01%,并生成0.76%甲酸和3.17%乙酸。采用每克纤维素20.0 FPIU的纤维素酶用量水解5%(w/w)该汽爆红柳物料48 h,纤维素酶水解得率可达到86.6%(未处理的原料仅为15.5%)。这表明无化学品添加的蒸汽爆破是适于红柳糖化及生物炼制的一种有效的预处理方法。

Abstract:

It’s essential and important to carry out research on the Tamarix ramosissima high-valued biorefining for promoting national land afforestation, ecological construction and agricultural income as Tamarix ramosissima plant is a kind of aboundant lignocellulosic resources in western China. In this study effects of steam explosion intensity(lgR)on the woody components and cellulose enzymatic hydrolysis performance of Tamarix ramosissima were presented during steam explosion pretreatment(SEP). The result showed that SEP hardly changed the contents of cellulose and sulfuric acid insoluble lignin in Tamarix ramosissima, however, it could break effectively the native structure of Tamarix ramosissima and promote most xylan to degrade into xylose by its auto-hydrolysis, in which some small molecule derivates came together, such as acetic acid, formic, furfural and so on. In view of the recovery ratio and the enzyme hydrolysis yield of cellulose in Tamarix ramosissima, maximum glucose yields upon enzymatic hydrolysis were obtained after pretreatment at 210℃ for 10 min. Based on the cellulose recovery rate and the cellulose hydrolysis yield, the optimum steam explosion pretreatment conditions for Tamarix ramosissima biorefinery was at the lgR value of 4.239(steam explosion temperature was 210℃, residence time was 10 min). And in the steam-exploded Tamarix ramosissima the cellulose content reached the highest value of 52.4%, while the residual xylan was only 2.01%, and generated 0.76% formic acid and 3.17% acetic acid. The enzymatic hydrolysis yield of cellulose in the steam exploded Tamarix ramosissima raised to 86.6% from 15.5% of the native material at lgR =4.239 with the cellulase loading of 20.0 FPIU/(g cellulose)after reaction for 48 h. Overall, this study showed that steam explosion without an acid catalysis is a good pretreatment method for saccharification of Tamarix ramosissima. Optimal steam explosion conditions need to be a compromise between sugar accessibility and sugar degradation.

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