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.

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