本文選題：右旋糖酐蔗糖酶 + 高分子右旋糖酐��； 參考：《合肥工業(yè)大學(xué)》2017年碩士論文

【摘要】：右旋糖酐是一類(lèi)在醫(yī)學(xué)和工業(yè)領(lǐng)域有重要作用的中性多糖,可合成高效、環(huán)保的新型生物多糖絮凝劑,具有廣闊的應(yīng)用前景。該生物多糖絮凝劑的絮凝性能與右旋糖酐分子量及其改性作用有關(guān)。本研究在前期研究的基礎(chǔ)上進(jìn)行了高分子量右旋糖酐的生產(chǎn)工藝研究,并對(duì)高分子右旋糖酐進(jìn)行接枝共聚和酯化改性,獲得了有良好絮凝性能的生物多糖絮凝劑,具體研究結(jié)果如下:(1)論文首先從改變底物濃度、酶用量和投料方式出發(fā),對(duì)右旋糖酐蔗糖酶以蔗糖為底物催化合成高分子右旋糖酐的工藝進(jìn)行了研究。實(shí)驗(yàn)結(jié)果表明,當(dāng)蔗糖底物濃度為1000mM,右旋糖酐蔗糖酶投加量為0.8U/mL時(shí),在25℃條件下發(fā)酵24小時(shí)可獲得分子量為1132萬(wàn)的右旋糖酐;采用濃度由高到低的均衡間歇補(bǔ)料方式可以使合成的右旋糖酐分子量更高。研究發(fā)現(xiàn)酶催化反應(yīng)副產(chǎn)物果糖的積累會(huì)抑制右旋糖酐鏈的增長(zhǎng),反應(yīng)后期體系粘度的增高會(huì)阻礙右旋糖酐鏈的延長(zhǎng)。(2)其次對(duì)高分子右旋糖酐與丙烯酰胺(AM)的接枝共聚反應(yīng)進(jìn)行研究,獲取具有良好絮凝性能的右旋糖酐衍生物,并分析了接枝產(chǎn)物的絮凝機(jī)制。實(shí)驗(yàn)結(jié)果表明,當(dāng)引發(fā)劑濃度為2mmol/L,m(AM):m(右旋糖酐)為2.0:1,反應(yīng)時(shí)間為3.5小時(shí),反應(yīng)溫度為35℃時(shí),接枝反應(yīng)單體轉(zhuǎn)化率達(dá)到95.4%。模擬水樣絮凝實(shí)驗(yàn)結(jié)果表明,pH為6.0時(shí),投入0.5mg/L接枝產(chǎn)物處理赤鐵礦懸濁液時(shí)去濁度為94%,投入4.15mg/L接枝產(chǎn)物處理高嶺土懸濁液時(shí)去濁度為91.2%。絮凝劑在絮凝過(guò)程中起主要作用的是電中和和架橋吸附,同時(shí)伴隨網(wǎng)捕、基團(tuán)反應(yīng)等多種作用發(fā)生,協(xié)同絮凝。(3)最后對(duì)高分子右旋糖酐與氨基酸的酯化反應(yīng)進(jìn)行了初探,對(duì)酯化產(chǎn)物進(jìn)行了結(jié)構(gòu)、性質(zhì)分析并檢測(cè)其絮凝性能。實(shí)驗(yàn)結(jié)果表明,酯化過(guò)程破壞了右旋糖酐分子的無(wú)定形區(qū)并對(duì)糖酐的結(jié)晶區(qū)也產(chǎn)生影響,酯化過(guò)程反應(yīng)速率慢,取代程度不高。高嶺土實(shí)驗(yàn)結(jié)果表明,該產(chǎn)物在酸性條件下絮凝效果較好,酯化產(chǎn)物投加量為15mg/L時(shí),去濁度可達(dá)91.7%。高分子右旋糖酐的酯化產(chǎn)物在水溶液中呈無(wú)規(guī)則線型分布,具有可伸展性和柔順性,含有多個(gè)吸附位點(diǎn),對(duì)水體系中的膠體顆粒有較好的凝集成團(tuán)能力,促進(jìn)雜質(zhì)的沉降。綜上,本研究為高分子量右旋糖酐催化合成與工業(yè)化生產(chǎn)提供了理論依據(jù),為高分子量右旋糖酐衍生物的合成與多糖絮凝劑的制備及其應(yīng)用打下基礎(chǔ)。
[Abstract]:Dextran is a kind of neutral polysaccharide which plays an important role in medicine and industry. It can be used as a new biological polysaccharide flocculant with high efficiency and environmental protection. The flocculation property of the biopolysaccharide flocculant is related to the molecular weight of dextran and its modification. On the basis of previous studies, the production process of high molecular weight dextran was studied, and the graft copolymerization and esterification modification of high molecular weight dextran were carried out, and the biopolysaccharide flocculant with good flocculation performance was obtained. The main results are as follows: (1) in order to change the substrate concentration, the amount of enzyme and the way of feeding, the process of synthesis of polymer dextran catalyzed by sucrose by sucrose was studied in this paper. The results showed that when the concentration of sucrose substrate was 1000mm and the dosage of dextran sucrase was 0.8U/mL, the dextran with molecular weight of 11.32 million could be obtained by fermentation at 25 鈩，

本文編號(hào)：1827372