本文選題：纖維素溶劑　切入點(diǎn)：玉米秸稈　出處：《江蘇大學(xué)》2017年碩士論文

【摘要】：木質(zhì)纖維素是地球上儲(chǔ)量最大的可再生資源,利用木質(zhì)纖維素制備生物乙醇是緩解環(huán)境和能源問(wèn)題的重要途徑之一。在長(zhǎng)期的自然進(jìn)化過(guò)程中,植物細(xì)胞壁形成了抵御酶降解及外部微生物的復(fù)雜結(jié)構(gòu)。由于底物結(jié)構(gòu)及酶解過(guò)程體系的復(fù)雜性,傳統(tǒng)預(yù)處理方式存在著效率低和能耗高等缺點(diǎn)。與傳統(tǒng)預(yù)處理相比,基于纖維素溶劑的木質(zhì)纖維素預(yù)處理方法在預(yù)處理?xiàng)l件和預(yù)處理效果等方面具有一定的優(yōu)勢(shì)。本論文使用纖維素溶劑對(duì)玉米秸稈進(jìn)行預(yù)處理,通過(guò)對(duì)比不同纖維素溶劑的預(yù)處理效果,篩選出適用于玉米秸稈的預(yù)處理方法,從經(jīng)過(guò)高效預(yù)處理的玉米秸稈中提取木質(zhì)素,初步探索預(yù)處理對(duì)木質(zhì)素物理化學(xué)結(jié)構(gòu)的影響;進(jìn)一步擴(kuò)大篩選出的纖維素溶劑的適用范圍,研究其對(duì)麥稈的預(yù)處理效果,同時(shí)分析預(yù)處理液固比對(duì)預(yù)處理效果的影響;對(duì)傳統(tǒng)的預(yù)處理與酶解糖化工藝進(jìn)行改良,提出利用預(yù)處理與酶解糖化“一鍋法”制備可發(fā)酵糖的方法,探究該方法可行性,并與傳統(tǒng)“分步法”進(jìn)行對(duì)比,分析其優(yōu)越性。本論文的主要研究成果歸納如下:(1)酸性和堿性纖維素溶劑預(yù)處理后,玉米秸稈的酶解轉(zhuǎn)化率都得到了大幅提升。它們都是通過(guò)破壞纖維素分子內(nèi)和分子間的氫鍵,從而破壞纖維素的剛性結(jié)構(gòu),同時(shí)去除玉米秸稈中一定量的半纖維素和木質(zhì)素,降低生物質(zhì)的頑抗性,提高酶解糖化效果。與85%濃磷酸相比,低溫NaOH/尿素溶液對(duì)玉米秸稈預(yù)處理效果較好。其中,在酶加載量為15 FPU/g底物的條件下,酶解24 h后,葡聚糖可以完全轉(zhuǎn)化為葡萄糖。(2)85%濃磷酸預(yù)處理后,底物中存在大量的木質(zhì)素,雖然纖維素結(jié)晶度降低較多,但沒(méi)有獲得較高的酶解轉(zhuǎn)化率。研究表明,與纖維素結(jié)晶度相比,木質(zhì)素對(duì)玉米秸稈酶解糖化的效果影響較大。通過(guò)對(duì)木質(zhì)素的初步探索發(fā)現(xiàn),低溫NaOH/尿素預(yù)處理后的木質(zhì)素“核心”結(jié)構(gòu)沒(méi)有被破壞,含有較多的化學(xué)活性基團(tuán),可能具有較好的化學(xué)活性。(3)低溫NaOH/尿素溶液對(duì)麥稈同樣具有良好的預(yù)處理效果。在酶加載量為15 FPU/g底物條件下,酶解糖化48 h,葡聚糖轉(zhuǎn)化率可達(dá)95%,木聚糖轉(zhuǎn)化率為84%。不同預(yù)處理液固比對(duì)麥稈中纖維素結(jié)晶度具有一定影響,但對(duì)麥稈的化學(xué)成分和酶解性能沒(méi)有顯著影響,這為高固載量預(yù)處理生物質(zhì)的進(jìn)一步研究提供了參考。(4)低溫NaOH/尿素預(yù)處理與酶解糖化“一鍋法”是可行的。最優(yōu)預(yù)處理與酶解糖化條件下,葡聚糖與木聚糖的酶解轉(zhuǎn)化率均可達(dá)到90%以上。“一鍋法”可以產(chǎn)生比傳統(tǒng)“分步法”更多的可發(fā)酵糖,其產(chǎn)生的可發(fā)酵糖占原料中總糖的90.24%,明顯高于傳統(tǒng)“分步法”的73.17%。低溫NaOH/尿素預(yù)處理液中不含有如糠醛和5-羥甲基糠醛發(fā)酵抑制物,該方法具有廣闊的應(yīng)用前景。
[Abstract]:Lignocellulose is the largest renewable resource on the earth. Bioethanol using lignocellulose is one of the important ways to alleviate the environmental and energy problems.During long term natural evolution, plant cell walls formed complex structures resistant to enzyme degradation and external microorganisms.Because of the complexity of substrate structure and enzymatic hydrolysis process, the traditional pretreatment method has the disadvantages of low efficiency and high energy consumption.Compared with the traditional pretreatment, the lignocellulose pretreatment method based on cellulose solvent has some advantages in pretreatment conditions and pretreatment effect.In this paper, cellulose solvent was used to pretreat corn straw. By comparing the pretreatment effect of different cellulose solvents, the suitable pretreatment method for corn straw was selected, and the lignin was extracted from the corn straw which was pretreated with high efficiency.The effect of pretreatment on the physicochemical structure of lignin was explored preliminarily, the suitable range of cellulose solvent was expanded, the effect of pretreatment on wheat stalk was studied, and the effect of pretreatment liquid / solid ratio on pretreatment effect was analyzed.The traditional pretreatment and enzymatic saccharification process were improved, and the method of preparing fermentable sugar by pretreatment and enzymatic saccharification "one pot method" was put forward. The feasibility of this method was explored, and compared with the traditional "step by step method", the superiority of the method was analyzed.The main research results of this paper are summarized as follows: 1) after pretreatment with acidic and alkaline cellulose solvents, the conversion rate of enzymatic hydrolysis of corn straw was greatly improved.All of them destroy the rigid structure of cellulose by destroying the hydrogen bond in and between molecules of cellulose. At the same time, they remove a certain amount of hemicellulose and lignin from corn straw, reduce the resistance of biomass, and improve the effect of enzymatic hydrolysis and saccharification.Compared with 85% concentrated phosphoric acid, the pretreatment effect of low temperature NaOH/ urea solution was better than that of 85% concentrated phosphoric acid.Under the condition of enzyme loading of 15 FPU/g substrate and enzymatic hydrolysis for 24 h, dextran could be completely converted into glucose, 2n 85% concentrated phosphoric acid pretreatment, and there was a large amount of lignin in the substrate, although the crystallinity of cellulose decreased more.But no higher enzymatic conversion was obtained.The results showed that lignin had a greater effect on the enzymatic hydrolysis and saccharification of corn straw than cellulose crystallinity.Through the preliminary study of lignin, it was found that the "core" structure of lignin treated with NaOH/ urea at low temperature was not destroyed and contained more chemical active groups.NaOH/ urea solution at low temperature also has good pretreatment effect on wheat straw.The conversion rate of dextran and xylan was 95 and 84 respectively under the condition of enzyme loading of 15 FPU/g substrate and enzymatic hydrolysis and saccharification for 48 h.The crystallinity of cellulose in wheat straw was influenced by different ratio of pretreatment liquid to solid, but had no significant effect on the chemical composition and enzymatic hydrolysis performance of wheat stalk.This provides a reference for the further study of biomass pretreatment with high solid load.) the pretreatment of low temperature NaOH/ urea and enzymatic hydrolysis and saccharification are feasible.The conversion rate of dextran and xylan could reach above 90% under the optimal pretreatment and enzymatic saccharification conditions.The "one-pot method" can produce more fermentable sugar than the traditional "step method". The fermentable sugar accounted for 90.24% of the total sugar in the raw material, which is obviously higher than that of the traditional "step method" 73.17%.Low temperature NaOH/ urea pretreatment solution does not contain such as furfural and 5-hydroxymethylfurfural fermentation inhibitors. This method has a broad application prospect.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ352.1;X712

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 周妍;趙雪冰;劉德華;;非離子型表面活性劑對(duì)木質(zhì)纖維素酶催化水解的影響及機(jī)理[J];化學(xué)進(jìn)展;2015年11期

2 王錢錢;魏薇;孫建中;劉玉;;基于纖維素溶劑的木質(zhì)纖維素預(yù)處理方法的研究進(jìn)展[J];造紙科學(xué)與技術(shù);2015年05期

3 王瓊;莊新姝;袁振宏;許敬亮;亓偉;余強(qiáng);;磷酸丙酮法分離玉米芯三組分的研究[J];可再生能源;2014年12期

4 張智衡;馬建鋒;許鳳;;結(jié)香纖維素與木素分布的顯微激光拉曼光譜研究[J];光譜學(xué)與光譜分析;2012年04期

5 楊梅;袁文杰;鳳麗華;;菊芋生料聯(lián)合生物加工發(fā)酵生產(chǎn)燃料乙醇[J];安徽農(nóng)業(yè)科學(xué);2012年09期

6 李江;謝天文;劉曉風(fēng);;木質(zhì)纖維素生產(chǎn)燃料乙醇的糖化發(fā)酵工藝研究進(jìn)展[J];化工進(jìn)展;2011年02期

7 袁同琦;何靜;許鳳;孫潤(rùn)倉(cāng);;生物質(zhì)資源研究的新視野——木質(zhì)纖維素全溶體系[J];化學(xué)進(jìn)展;2010年Z1期

8 功靚;卓小龍;沈青;;纖維素功能化研究的新進(jìn)展 Ⅱ.纖維素功能化的新型溶劑[J];纖維素科學(xué)與技術(shù);2010年01期

9 胡愛(ài)華;邢世巖;鞏其亮;;基于FTIR的針闊葉材木質(zhì)素和纖維素特性[J];東北林業(yè)大學(xué)學(xué)報(bào);2009年09期

10 李琳;趙帥;胡紅旗;;纖維素溶解體系的研究進(jìn)展[J];纖維素科學(xué)與技術(shù);2009年02期

相關(guān)碩士學(xué)位論文 前1條

1 程明楊;農(nóng)林廢棄物催化液化的研究[D];湖南大學(xué);2009年

，

本文編號(hào)：1707268