以兩階段濕氧蒸爆技術處理狼尾草同時生產木寡糖與高消化率芻料的研究

Two-Stage Wet Oxidative Steam Explosion of Napiergrass for the Production of Xylo-oligosaccharides and Animal Feed of High Digestibility

黃俊鴻(Chun-Hung Huang 黃俊鴻)

指導教授 ： 余琬琴

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00451

摘要

狼尾草是深具潛力的能源作物，此外在台灣狼尾草汁也被開發為健康食品，但其榨汁後的殘渣尚未有合適的利用。為了有效利用狼尾草，我們以濕氧蒸爆技術處理狼尾草渣，開發同時生產木寡糖與高消化率芻料的製程。
蒸爆法以高溫蒸氣處理物料，是一低污染的製程，可將木質纖維物料中的半纖維素降解成寡糖，溶在蒸爆液中，蒸爆後的固體經鹼浸泡去除木質素後，則可製成高消化率芻料。本研究採用兩階段濕氧蒸爆處理狼尾草，為了尋找最適合的濕氧蒸爆條件，我們利用實驗設計法，探討濕氧蒸爆反應時間與氧氣含量對木寡糖產量與狼尾草組成的影響，反應時間與氧氣含量的範圍分別為5~25 min與0~60%，蒸爆溫度則維持在190℃。蒸爆後的固體以80℃、5%(w/w)的氫氧化鈉溶液浸泡30 min去除木質素後，則以酵素法(pepsin-cellulase method)測定其消化率。研究結果顯示，濕氧蒸爆主要造成半纖維素的降解，經過兩階段濕氧蒸爆，木寡糖與可溶性木聚醣總產率最高達52.7%；木質素的移除率隨蒸爆強度的增加而提升，增加氧氣濃度的效應尤其顯著，但是需將蒸爆過的狼尾草搭配鹼處理才會有效的移除木質素及提升消化率。消化率最高達62.4%，與未經處理前的22.9%相較，消化率上升大約40%。

關鍵字

木質纖維素 ； 狼尾草 ； 蒸爆法 ； 木寡糖 ； 消化率 ； 實驗設計

並列摘要

Napiergrass (Pennisetum purpureum) is regarded as a potential energy crop and can be used for the production of fuels and chemicals. In addition, Napiergrass juice prevails recently in Taiwan as a functional juice due to its beneficial health effects. However, the fibrous residues after juice extraction have not yet found suitable uses. In order to fully utilize the Napiergrass biomass, we investigated the clean fractionation of Napiergrass using the wet-oxidative steam explosion technology.
In this study, the wet-oxidative steam explosion was performed in two stages under a constant temperature of 190℃. The effects of residence time and oxygen content on xylooligosaccharide production and residual solid composition were investigated using a factorial experimental design. The residence time ranged from 5 to 25 min and the oxygen content from 0 to 60%. The steam explosion conditions were optimized for the production of xylooligosaccharides. The residual solids after steam explosion were subjected to a further alkaline delignification step before their digestibility was determined using the pepsin-cellulase method. The alkaline delignification was carried out with a 5% (w/w) sodium hydroxide solution at 80℃for 30 min.
Napiergrass were subjected to wet oxidative (WO) steam explosion, followed by an alkaline treatment. By two stages wet oxidative (WO) steam explosion. The total yield of Xylo-oligosaccharides and solubility xylan yield up to 52.7%. The digestibility from 22.9% up to 62.4%. The effects of WO steam explosion residence time and oxygen content on Xylo-oligosaccharides and lignin removal and digestibility were studied using experimental design. When Xylo-oligosaccharides are considered as a product, a milder WO steam explosion condition should be used.

並列關鍵字

biomass ； lignocellulose ； Napiergrass ； steam explosion ； digestibility ； Xylo-oligosaccharides ； pepsin-cellulase method ； experimental design

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