以前處理台灣赤楊生產木寡糖及乳酸

Xylooligosaccharides and lactic acid production from pretreated Alnus formosana biomass

劉冠宏(Guan-Hong Liou)

指導教授 ： 柯淳涵

國立臺灣大學/生物資源暨農學院/森林環境暨資源學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201602753

摘要

本研究為以多種方法處理台灣原生種植物台灣赤楊，並製備全纖維素衍生產物。先將台灣赤楊木片分別浸泡於水與1.5% 硫酸96 h，接著放入蒸解槽進行蒸氣爆碎，其處理條件為180oC持溫10 min之後再將水蒸爆生質物進行生石灰法(RT-CaCCO與CaCCO) 的進一步處理，成為數種前處理法之台灣赤楊原料。步驟，包含分為兩部分產物製備: (1) 以NaOH提取台灣赤楊之戊聚糖，經不同步驟純化分離成木聚糖，再經酵素水解成木寡糖。(2) 以不同前處理方法之配合，破壞生質物之化學組成結構，以提高後續水解成葡萄糖與發酵成最終產物乳酸的效率。第一部分將未處理與經過蒸氣爆碎的台灣赤楊進行戊聚糖之萃取，萃取條件為加入生質物重量10倍之12% NaOH 體積，持溫60oC與150 rpm 反應16 h，之後分為酒精沉澱、酒精沉澱混合膜過濾以及單純膜過濾三種純化方法收取木聚糖。1% 木聚糖會以10、50、100 IU/mL 三種酵素劑量進行水解試驗，找出最佳的純化方法、酵素劑量、水解時間。結果發現，僅使用酒精沉澱之木聚糖生成的木寡糖濃度最高，為8.26 mg/mL；最佳酵素劑量則根據不同的條件有不同結果，均為50、100 IU/mL兩種酵素劑量為較佳；最佳水解時間為三天之內。第二部分實驗中，將這些原料進行同時糖化與發酵 (SSF)，測定乳酸的產率。結果發現，1.5% 硫酸可有效率的破壞生質物結構，原料在酵素水解四天時產糖量為4.00 g/L，水解效率為53.35%。而SSF實驗中得知四天時乳酸產量為6.22 g/L，在十天時產量為11.51 g/L,其效率為0.048 gL-1h-1。數種前處理對台灣赤楊的利用效率比較為: 稀酸蒸氣爆碎>打漿>生石灰法。

關鍵字

台灣赤楊 ； 蒸氣爆碎 ； RT-CaCCO ； 木寡糖 ； 膜過濾 ； 乳酸

並列摘要

Alnus formosana is a native species of central Taiwan. In order to take good use of the biomass, pretreatments including H2O steam explosion (HSE), 1.5% sulfuric acid steam explosion (ASE), RT-CaCCO (room temperature-calcium capturing by carbonation) and CaCCO (calcium capturing by carbonation) processes, and beating methods are conducted before production of xolooligosacchrides (XOs) and lactic acid production.
In XOs production, untreated and HSE A. formosana were mixed with 12% (w/v) NaOH solution with the liquid / solid ratio of 10. The mixtures were extracted at 150 rpm and 60oC for 16 hr. The mixtures were filtered and the filtrates were adjusted to pH 7 by HCl, and then they were mixed with EtOH and purified by ultrafiltration or nanofiltration. Then xylan was oven dried and conserved. 1% xylan was hydrolyzed by 10, 50, 100 IU/mL of enzymes to produce XOs. Results showed that xylan only conducted by EtOH treatment obtained the highest XOs, with 8.26 mg/mL. There were no significant differences between untreated and HSE A. formosana xylan on XOs production.
In lactic acid production, A. formosana pretreated by steam explosion, lime (RT-CaCCO and CaCCO), and beating methods were conducted by simultaneous hydrolysis and fermentation (SSF) to produce lactic acid. Results showed that A. formosana with 1.5% sulfuric acid steam explosion (ASE) pretreatment obtained the highest glucose concentration 4.00 g/L in enzyme hydrolysis at Day 4, and the efficiency was 53.35%. And SSF of ASE also resulted in the highest lactic acid production, with 6.22 g/L at Day 4 and 11.51 g/L at Day 10, and the productivity was 0.048 gL-1h-1. The impacts of pretreatment efficiencies mentioned above were ASE > beating > lime.

並列關鍵字

Alnus formosana ； steam explosion ； beating ； RT-CaCCO ； lactic acid ； xlooligosaccharids

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