纤维素降解细菌的筛选及其酶活测定

为了充分利用植物废渣中丰富的纤维素资源,以羧甲基纤维素钠(CMC-Na)为唯一碳源的培养基和刚果红染色筛选法从朽木周围富含腐殖质的土壤中筛选得到3株活性较高的纤维素降解细菌：ZWY-3、DP-6和DP-8,并分别在不同的培养时间、培养温度、起始pH、碳源下对3株菌株进行酶活测定。结果表明：3株菌株都在接种后24 h、pH 7、30℃、葡萄糖为碳源时达到产酶高峰,其中接种后24 h时DP-6的酶活最高,达144.86 U;ZWY-3在30℃、pH 7时酶活最大,分别达126.74 U和133.82 U;3株菌株在其最适条件下培养,并以葡萄糖为碳源时,DP-6活性最高,可达218.96 U。3株细菌菌株在降解农业纤维工业中具有良好的应用前景。     

Cellulose aerogels decorated with multi-walled carbon nanotubes: preparation,characterization, and application for electromagnetic interference shielding

Electromagnetic wave pollution has attracted extensive attention because of its ability to affect the operation of electronic machinery and endanger human health. In this work, the environmentally-friendly hybrid aerogels consisting of cellulose and multi-walled carbon nanotubes (MWCNTs) were fabricated. The aerogels have a low bulk density of 58.17 mg·cm⁻³. The incorporation of MWCNTs leads to an improvement in the thermal stability. In addition, the aerogels show a high electromagnetic interference (EMI) SE_total value of 19.4 dB. Meanwhile, the absorption-dominant shielding mechanism helps a lot to reduce secondary radiation, which is beneficial to develop novel eco-friendly EMI shielding materials.     

Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications

Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress–strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity.     

球磨处理玉米秸秆纤维素原料的工艺参数优化(简报)

研究了玉米秸秆水解过程中球磨预处理工艺的优化,采用Plackett- Burman(PB) 试验设计和均匀试验设计法,用数据处理软件对试验结果进行分析,筛选出了球磨预处理过程中的主要影响因素,得到了具有较好拟合度的回归方程;通过分析原料粒径(mm),转速（r/min）,原料填装量（g）,研磨介质,交替时间（min）等球磨条件对酶解效率的影响,得出行星式球磨机粉碎玉米秸秆的最佳工艺参数为：原料粒径0.5 mm,转速340 r/min,原料填装量3.4 g,装球量15个（Ф=10.0 mm）,交替运行时间5 min。     

纤维素酶在改善奶牛生产性能方面的应用进展

纤维素酶具有广泛的应用价值。近年来,纤维素酶逐渐被应用于奶牛生产中,并取得了很好的效果,它可有效提高奶牛产奶量,提高经济效益。本文综述了纤维素酶的分类、作用机理及国内外纤维素酶对奶牛生产性能方面的最新进展。     

甘蔗渣纤维素提取及木质素与半纤维素脱除工艺探讨

为了获取优质的纤维素,以甘蔗渣为原料,通过对纤维素提取工艺的探讨,确定了既能保持纤维素提取量,又可较多脱除木质素的工艺条件。试验结果表明,最优工艺条件为质量分数为4%的NaOH溶液和含量为0.7%的H2O2混合液处理,反应温度为85℃,NaClO2处理浓度为9.5 g/L。在此条件下,提取的甘蔗渣纤维素含量为82.73%,木质素的脱除率为94.44%,半纤维素的脱除率为75.54%,从而得到了纯度较高的优质甘蔗渣纤维素。     

超声波一步法制备纤维素氯化锂/二甲基乙酰胺溶液

运用超声波一步法制备了纤维素氯化锂/二甲基乙酰胺的离子溶液。通过调节超声波功率和处理时间,对纤维素、氯化锂和二甲基乙酰胺混合物超声波处理5~7 min,并于室温下搅拌3~5 h,即可获得纤维素均匀溶液;研究了超声波处理对纤维素分子及形态结构的影响,并对纤维素溶液的流变性能进行了考察。结果表明,超声波一步法具有工艺简单、易操作以及溶解时间短的特点,所得到的纤维素溶液具有高分子溶液的一般特征。     

可利用纤维素产油脂的意杨内生真菌的筛选与发酵条件研究

从意大利白杨韧皮部中筛选得到一株能够利用纤维素并高产油脂的内生真菌,初步鉴定为茎点霉属.利用意杨树叶粉碎物作为唯一碳源进行液体发酵,该菌株在培养至第8天时,油脂产量和滤纸酶活力达到最高,分别为0.78g/L、5.67mg/(L·min)(以葡萄糖计).通过单因子分析及正交优化试验,得到发酵条件最佳组合为:玉米秆50g/L,NH4NO3 3g/L,温度25℃,摇床转速150r/min,此时真菌油脂产量达到1.12g/L.分析菌体发酵获得的油脂成分,主要为软脂酸、硬脂酸、油酸、亚油酸,可以作为生物柴油的原料.     

生物质糖化和乙醇发酵菌种资源的研究进展

世界能源安全正面临着挑战。发展清洁可再生的生物质燃料乙醇越来越被重视。菌种资源在燃料乙醇生产中起到至关重要的作用。概述了生物质糖化和乙醇发酵菌种资源的研究进展,并展望了今后的研究方向。     

棉花纤维素合酶基因GhcelA1克隆及其载体构建

 根据GeneBank 中GhcelA1（U58283）序列,利用RT-PCR技术,从棉纤维中克隆到GhcelA1 cDNA全长。运用基因重组技术,构建pCAM2300-35S-GhcelA1过表达载体;融合基因表达载体pCAM2300-35S-GhcelA1-EGFP,以及pCAM2300-35S-GhcelA1-RNAi载体,这些载体均通过限制性酶切鉴定和测序验证。农杆菌介导法将融合基因转化棉花子叶,通过激光共聚焦荧光显微镜,在蓝色激发光下观察诱导的愈伤,发现在转化的活体细胞核与质膜内侧有绿色荧光,说明融合基因载体EGFP构建正确,可以在棉花中正常表达。所构建的系列载体可用于转化棉花,促进纤维素在棉纤维中合成与积累。