本文選題：漆酶 + 降解�。� 參考：《廣西大學》2017年碩士論文

【摘要】：隨著人類社會的快速發(fā)展,世界能源的消耗量也日益加劇,三大能源(煤、石油、天然氣)畢竟來源有限,早已不能滿足人類社會的需要。另一方面,人工合成物質(zhì)的潛在危害性也加劇了科學家向天然可再生產(chǎn)物領(lǐng)域的研究進程。木質(zhì)素是自然界中含量僅次于纖維素的一類可再生有機物,它來源廣泛,化學結(jié)構(gòu)復雜,具有一定的抗氧化性,但其抗氧化性遠遠低于人工合成的抗氧化劑。本文通過漆酶降解的方法來提高木質(zhì)素的抗氧化性,為木質(zhì)素可作為天然抗氧化劑提供理論支持,增加木質(zhì)素綜合利用的附加價值。主要的研究內(nèi)容與結(jié)果如下:(1)利用漆酶降解堿木質(zhì)素(AL),并從溶劑pH值、反應溫度、反應時間、漆酶添加量等因素,探究對其抗氧化能力的影響,得到最佳降解條件為:pH=5.0、T=25℃、t=6h、V酶=1.2mL·g-1(AL)。(2)采用DPPH法表征堿木質(zhì)素的抗氧化能力,實驗結(jié)果表明:降解堿木質(zhì)素(DAL)的抗氧化能力(IC50=56.75μg·mL~(-1))明顯強于AL(IC50=396.2μg·mL~(-1));FTIR、SEM、粒徑、GPC等分析手段表明:降解之后,堿木質(zhì)素的主要官能團沒有改變,分子變小和更松散,分子量也變小;在主要官能團含量測定實驗中發(fā)現(xiàn):DAL的酚羥基含量(1.39 mmol·g-1)明顯高于 AL(0.512mmol·g-1),甲氧基含量(1.06 mmol·g-1)低于 AL(4.06 mmol·g-1)。降解之后,酚羥基含量的劇增和降解產(chǎn)物分子形貌的改變,使得DAL的抗氧化能力強于AL。(3)利用漆酶降解水解木質(zhì)素(HL),并從溶劑pH值、反應溫度、反應時間、漆酶添加量等因素,探究對其抗氧化能力的影響,得到最佳降解條件為:pH=5.6、T=35 ℃、t=4h、V酶=1.0mL·g-1(HL)。(4)采用DPPH法表征水解木質(zhì)素的抗氧化能力,實驗結(jié)果表明:降解水解木質(zhì)素(DHL)的抗氧化能力(IC50=28.78 μg·mL~(-1))強于HL(IC50=31.25μg·mL~(-1));FTIR、SEM、粒徑、GPC等分析手段表明:降解之后,水解木質(zhì)素的主要官能團沒有改變,分子變小和更松散,分子量也變小;在主要官能團含量測定實驗中發(fā)現(xiàn):DHL的酚羥基含量(1.96 mmol·g-1)高于 HL(1.81mmol·g-1),甲氧基含量(7.53mmol·g-1)也高于HL(4.22 mmol·g-1)。降解之后,甲氧基含量的大幅度提升,即使是在酚羥基小幅度提升的前提下,再加上分子形貌的改變,使得DHL的抗氧化能力還是強于HL。(5)酚羥基是決定抗氧化能力最主要的官能團,其含量越高,抗氧化能力越強;甲氧基能促進抗氧化能力的提高,其含量越高,效果越明顯。
[Abstract]:With the rapid development of human society, the consumption of energy in the world is increasing day by day. After all, the three major energy sources (coal, oil, natural gas) are limited, and can not meet the needs of human society. On the other hand, the potential harmfulness of synthetic substances also intensifies the research progress in the field of natural renewable products. Lignin is a kind of renewable organic substance in nature, which is second only to cellulose in content. It has a wide range of sources, complex chemical structure and certain antioxidant properties, but its antioxidant activity is far lower than that of synthetic antioxidants. In this paper, the method of laccase degradation is used to improve the antioxidant ability of lignin, which can provide theoretical support for lignin as a natural antioxidant and increase the added value of comprehensive utilization of lignin. The main research contents and results are as follows: (1) using laccase to degrade alkali-lignin (ALP) and to explore the effects of solvent pH value, reaction temperature, reaction time, laccase addition and other factors on its antioxidant ability. The optimum degradation conditions were obtained as follows: ph: 5. 0 ~ (5. 0) T ~ (2 +) = 1. 2 mL / g ~ (-1) ALN. 2) Antioxidant ability of alkali lignin was characterized by DPPH method. The results showed that the antioxidant capacity of alkaline lignin was 56.75 渭 g / mL ~ (-1), which was obviously better than that of AL(IC50=396.2 渭 g / mL ~ (-1) ~ (-1) DPPH. The results showed that: after degradation, the antioxidation ability of alkaline lignin was 56.75 渭 g / mL ~ (-1), which was obviously better than that of AL(IC50=396.2 渭 g / mL ~ (-1) / L ~ (-1). The main functional groups of alkali lignin were not changed, and the molecular weight became smaller and looser, and the content of phenolic hydroxyl group was 1.39 mmol / g ~ (-1), and the content of methoxy group was 1.06 mmol / g ~ (-1) lower than that of AL(4.06 mmol g ~ (-1). After degradation, the content of phenolic hydroxyl groups and the molecular morphology of degradation products increased dramatically, which made the antioxidant ability of DAL stronger than that of AL.3. The hydrolyzed lignin HLN was degraded by laccase, and the factors such as pH value of solvent, reaction temperature, reaction time, laccase addition, etc. The optimum degradation conditions were as follows: 1. 0ml / g-1hmg-1hl-1 HL-4 at 35 鈩，

本文編號：1879099