细菌纤维素结构控制及其应用研究

发布时间：2018-09-17 07:26

【摘要】：细菌纤维素(BaacterialCellulose,简称BC)是一种由木醋杆菌发酵得到的纤维素材料,具有高持水性、生物可相容性、化学易修饰性和生物可降解性。近年来,由于其优良的特性,BC在纺织、医药、食品、导电材料等领域具有良好的应用前景。目前,BC生产面临成本高、产量低的问题,同时其应用也存在性能单一的问题。因此,如何寻找廉价易得的发酵原料及增产因子,如何控制BC的三维网状结构及开发BC基复合材料,是推进BC工业化应用亟待解决的问题。在BC发酵生产方面。本文探究了以废弃物豆粕为发酵原料生产BC的可行性。实验结果表明,在硫酸浓度为1.5 wt%,料酸质量比为1:4,水解时间为20 h,水解温度为80℃的条件下预处理豆粕,得到的BC产量可达5.2 g/L,同时BC的氮源平均成本显示出极具竞争力的成本优势。在BC结构控制方面。首先,本文研究了添加氯化稀土(Rare Earth Chlorides,简称RECs)对木醋杆菌生长代谢及BC产量、形态结构的影响。根据RECs对BC 产量的影响,有 8 种 RECs(Sccl3、Prc13、Gdcl3、Dyc13、Ec13r、Ybcl3、Yc13、Tbc13)具有明显的促进作用;有 5 种RECs(Smcl3、Cecl3、Eucl3、Hoc13、Tmc13)具有明显的抑制作用;有3种RECs(Lac13、Ndc13、Luc13)影响不大,其中,当Lacl3的浓度由0 mg/L依次增加到20 mg/L和500 mg/L时,BC的结晶度由75.58%依次下降到68.11%和48.11%,孔隙率由97.3%依次下降到96.1%和97.1%。其次,研究了静态发酵24h内,不同直流电场强度对木醋杆菌生长代谢及BC形态结构的影响。结果发现,在10 mA电场下的培养基中部,BC纤维呈定向排列,且纤维直径由0 mA下的119.4 nm下降到74.7 nm。此外,BC的结晶度由0 mA的75.58%依次下降到培养基阴、阳极下的48.76%、58.59%,BC的孔隙率由97.3%分别下降到90.0%和92.8%。在BC复合材料制备及应用方面。一方面,通过溶液浸渍法和交联技术制备了 BC/ε-聚赖氨酸(BC/ε-PL)抗菌复合材料。研究发现,BC/ε-PL中ε-PL的含量可通过ε-PL溶液的浓度进行调整,且随着ε-PL浓度的提高,其对大肠杆菌和金黄色葡萄球菌的抗菌性也得到增强。其中,当ε-PL溶液的浓度在0.75 wt%时,其在24 h内对大肠杆菌的抑菌率为99.04%,对金黄色葡萄球菌的抑菌率为97.89%。另一方面,以BC为原料,通过溶液浸渍法、冷冻干燥和高温热解制备了氮磷硫共掺杂的细菌纤维素基碳纳米纤维电极材料(N/P/S-PBC),并将其应用于对称型超级电容器。结果表明,在1.0A/g的电流密度下,N/P/S-PBC电极材料的比电容为255 F/g,且功率密度为489.45 W/kg时,能量密度可达8.48 Wh/kg。
[Abstract]:Bacterial cellulose (BaacterialCellulose, for short BC) is a cellulose material fermented by Acetobacter xylem. It has high water holding capacity, biocompatibility, chemically easy modification and biodegradability. In recent years, BC has a good application prospect in textile, medicine, food, conductive materials and other fields because of its excellent properties. At present, the production of BC is faced with the problems of high cost and low output, at the same time, its application also has the problem of single performance. Therefore, how to find cheap and easily available raw materials and production factors, how to control the three-dimensional network structure of BC and how to develop BC matrix composites are the urgent problems to be solved in the industrial application of BC. In BC fermentation production. In this paper, the feasibility of producing BC from waste soybean meal was studied. The results showed that when the concentration of sulfuric acid was 1.5 wt%, the mass ratio of feed to acid was 1: 4, the hydrolysis time was 20 h, and the hydrolysis temperature was 80 鈩，

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