红托竹荪菌托多糖的提取及抗肿瘤活性的初步研究

红托竹荪菌托经热水提取、酒精沉淀、脱蛋白后的粗多糖,其得率远大于其菌丝体和子实体的其他部位及香菇子实体.菌托粗多糖进一步用DEAE纤维素柱和Sephadex G-75分离纯化,得到两个组分DRVP1与DRVP2,对分离得到的主要多糖通过高效液相色谱(HPLC)、红外光谱(IR)等进行结构分析.DRVP1的相对分子质量(Mr)为1.47×104,红外光谱数据显示为β-型甘露糖苷.体外试验表明,红托竹荪菌托多糖的组分DRVP1对小鼠S180肉瘤有一定的抑制作用.     

一株乳杆菌对蒸汽爆破处理纤维物料的乳酸发酵研究

用筛选得到的一株乳酸杆菌ZJU-1(Lactobacillus sp．)对蒸汽爆破预处理纤维物料的乳酸发酵进行了研究,结果表明该菌株能对蒸汽爆破处理的纤维物料酶解液进行乳酸发酵,在还原糖质量浓度为52．1mg/mL时,乳酸量为42．1mg/mL;与纤维素酶的酶解过程相耦合,对蒸汽爆破处理的物料进行同时糖化乳酸发酵。其发酵周期比分步糖化发酵的过程周期短,在底物质量分数为80mg/mL,接种量为10％,温度为45％时,乳酸量为45．3mg/mL。     

荞麦麸皮多糖的分离纯化及其外貌表征的分析

采用水提醇沉法对荞麦麸皮多糖(Buckwheat bran polysaccharide,BBP)进行提取,通过DEAE-52纤维素柱层析法和Sephadex G-200对其进行分离纯化,采用凝胶过滤法对多糖组分的分子量进行测定,采用扫描电镜对荞麦麸皮多糖及其分离纯化的多糖组分的外貌进行分析,用红外光谱对分离纯化的三个荞麦麸皮多糖组分的苷键构型进行分析。结果表明:DEAE-52纤维素和Sephadex G-200对荞麦麸皮粗多糖具有较好的分离纯化效果,得到了三个多糖组分(BBP-Ⅰ、BBP-Ⅱ和BBP-Ⅲ),其分子量分别为1.56×10~4Da、5.85×10~4Da、8.45×10~4Da。扫描电镜的结果表明,BBP其表面粗糙,凹凸不平,三个分离纯化的多糖组分形貌差异较大,分别以球状、片状、棒状为主。红外光谱扫描表明BBP-Ⅰ和BBP-Ⅲ为ɑ-糖苷键化合物,BBP-Ⅱ为β-糖苷键化合物。荞麦麸皮多糖组分外貌的差异性为其进一步的结构探究提供了重要依据。     

硒化紫球藻胞外多糖组成与结构的初步分析

通过在ASW培养基中加入适量的亚硒酸制备硒化紫球藻胞外多糖,经分离纯化、纯度鉴定后,利用下列手段对其进行分析:通过紫外可见光谱扫描、红外光谱扫描了解其结构信息;通过高效液相色谱对其单糖组分进行分析;通过硫酸-咔唑法测定其糖醛酸含量;通过硫酸比浊法测定其硫酸根含量,等。Se-PSP和PSP一样,分离后分别得到两种成分,紫外光谱也和PSP相似,不含有蛋白质和核酸;红外光谱显示Se-PSP中Se可能取代了C-H上的H和SO42-中的S;HPLC显示其单糖组分种类相似,含量稍有差别;另外,PSP和Se-PSP所含的糖醛酸含量没有统计学差异,Se-PSP所含SO42-比PSP少。     

沙果渣膳食纤维超高压处理条件优化及其微观结构表征

为制备高品质的沙果渣膳食纤维,研究超高压处理对沙果渣中膳食纤维的影响。以沙果渣为原料,采用响应面试验优化了超高压处理的料液比、压力和时间等条件,对优化后沙果渣膳食纤维的持水力、持油力、膨胀力和功能特性等理化性质进行了分析,并借助扫描电镜和红外光谱等方法分别对其微观结构与官能团进行表征。结果表明:最佳处理条件为处理压力300 MPa,时间15 min,料液比1∶19.30(g/mL),该条件下沙果渣膳食纤维的可溶性膳食纤维含量、持水力、持油力、膨胀力、阳离子交换能力、对胆固醇吸附量、吸附葡萄糖能力分别为21.71%、7.81 g/g、8.03 g/g、7.20 mL/g、0.78 mmol/g、14.31 mg/g和8.20 mg/g,与未处理样品相比,均有了显著提高(P0.05)。扫描电镜显示经超高压处理后的沙果渣膳食纤维样品与未经处理样品相比,呈现不规则形状,表面变得更加疏松多孔,网状及层状结构增多;红外光谱分析表明超高压处理后的沙果渣膳食纤维中有纤维素、半纤维素和木质素等的特征吸收峰。     

枯盘斑多毛孢Pf-毒素组分的研究I.活性组分I的结构分析

以正丁醇:水:甲醇(4:2:1)作洗脱剂,通过硅胶H60型柱反复柱层析,将3种有致病活性的物质充分纯化,在-40℃下冷冻干燥后,它们为褐色深浅不一的蓬松状物质,且极易吸潮。活性组分I(Rf0.83)、活性组分II(Rf0.79)和活性组分III(Rf0.80)对马尾松切根幼苗和湿地松切根幼苗针叶都有致萎作用,通过质谱(MS)、核磁共振谱(1HNMR、)和红外光谱(IR)等分析手段确定出所分离的活性组分I的化学组成为C5H11O5N(M=165)。     

人体劳宫穴红外辐射光谱特性研究

目的:比较正常人及冠心病患者两侧劳宫穴(PC8)微弱红外辐射光谱的差异性。方法:对47名正常人和50名冠心病患者左右侧劳宫穴红外辐射进行检测,通过光谱形态分析和点值比较的方法对两侧红外辐射光谱的差异进行研究。结果:人体两侧劳宫穴红外辐射光谱形态基本一致,但在辐射峰处两侧劳宫穴红外辐射强度有显著差异(P<0.05),正常人两侧劳宫穴辐射强度差值和冠心病患者相比并无显著性差异P>0.05。结论:劳宫穴的红外辐射不能灵敏地反应冠心病心肌缺血缺氧的病理状态,人体穴位红外辐射光谱无刺激性探测和分析为经穴特异性研究提供了新的途径。     

红外光谱技术在生物过程监测中的应用

在线监测化学组分的浓度对许多生物过程都是十分必要的。然而,探头需耐高温灭菌的要求和生物体系自身的复杂性给许多分析技术的在线监测带来了困难。近几年,随仪器和数据处理技术的迅速发展,应用红外光谱技术对生物过程的原位或在线监测日益广泛。本文对红外过程分析技术进行了较全面的综述,介绍了红外分析的原理、进展及在生物过程监测中的应用。     

枯盘斑多毛孢Pf-毒素组分的研究Ⅰ．活性组分Ⅰ的结构分析

以正丁醇：水：甲醇(4：2：1)作洗脱剂,通过硅胶H60型柱反复柱层析,将3种有致病活性的物质充分纯化,在-40℃下冷冻干燥后,它们为褐色深浅不一的蓬松状物质,且极易吸潮。活性组分Ⅰ(Rf0．83)、活性组分Ⅱ(Rf0．79)和活性组分Ⅲ(Rf0．80)对马尾松切根幼苗和湿地松切根幼苗针叶都有致萎作用,通过质谱(MS)、核磁共振谱(^1HNMR、)和红外光谱(IR)等分析手段确定出所分离的活性组分Ⅰ的化学组成为C5H11O5N(M=165)。     

稀土Ho-吲哚-3-乙酸配合物的合成及其生物活性的研究

以吲哚-3-乙酸为配体,合成了稀土钬的配合物。利用元素分析、红外光谱(IR)、热重-差热分析(TG-DTG)和荧光光谱(FS)等分析手段对配合物的组成和光学等性质进行了分析与表征,推测配合物的通式为Ho(L)3.2H2O;通过对荧光光谱的研究表明,稀土钬配合物具有较好的荧光性能;通过对其生物活性的表征说明吲哚乙酸与稀土硝酸盐在形成稀土配合物后,对植物的生长起到了协同促进作用。     

Isolation and characterization of cellulose nanofibrils from wheat straw using steam explosion coupled with high shear homogenization

Cellulose nanofibrils of diameter 10–50 nm were obtained from wheat straw using alkali steam explosion coupled with high shear homogenization. High shear results in shearing of the fiber agglomerates resulting in uniformly dispersed nanofibrils. The chemical composition of fibers at different stages were analyzed according to the ASTM standards and showed increase in α-cellulose content and decrease in lignin and hemicellulose. Structural analysis of steam exploded fibers was carried out by Fourier Transform Infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). Thermal stability was higher for cellulose nanofibrils as compared to wheat straw and chemically treated fibers. The fiber diameter distribution was obtained using image analysis software. Characterization of the fibers by AFM, TEM, and SEM showed that fiber diameter decreases with treatment and final nanofibril size was 10–15 nm. FT-IR, XRD, and TGA studies confirmed the removal of hemicellulose and lignin during the chemical treatment process.     

Unpolluted fractionation of wheat straw by steam explosion and ethanol extraction

An unpolluted process of wheat straw fractionation by steam explosion coupled with ethanol extraction was studied. The wheat straw was steam exploded for 4.5 min with moisture of 34.01%, a pressure of 1.5 MPa without acid or alkali. Hemicellulose sugars were recovered by water countercurrent extraction and decolored with chelating ion exchange resin D412. The gas chromatography (GC) and high-performance liquid chromatography (HPLC) analysis results indicated that there were organic acids in the hemicellulose sugars and the ratio of monosaccharides to oligosaccharides was 1:9 and the main component, xylose, was 85.9% in content. The total recovery rate of hemicellulose was 80%. Water washed materials were subsequently extracted with ethanol. The optimum extraction conditions in this work were 40% ethanol, fiber/liquor ratio 1:50 (w/v), severity log(R)=3.657 (180 degrees C for 20 min), 0.1% NaOH. The lignin yield was 75% by acid precipitation and 85% ethanol solvent was recovered. The lignin was purified using Bj?rkman method. Infrared spectrometry (IR) results indicated that the lignin belonged to GSH (guaiacyl (G) syringyl (S) and p-hydroxyphenyl (H)) lignin and its purity rate reached 85.3%. The cellulose recovery rate was 94% and the results of electron spectroscopy for chemical analysis (ESCA) and infrared spectrometry (IR) showed that hemicellulose and lignin content decreased after steam explosion and ethanol extraction.     

Structure, morphology and thermal characteristics of banana nano fibers obtained by steam explosion

In this work, cellulose nanofibers were extracted from banana fibers via a steam explosion technique. The chemical composition, morphology and thermal properties of the nanofibers were characterized to investigate their suitability for use in bio-based composite material applications. Chemical characterization of the banana fibers confirmed that the cellulose content was increased from 64% to 95% due to the application of alkali and acid treatments. Assessment of fiber chemical composition before and after chemical treatment showed evidence for the removal of non-cellulosic constituents such as hemicelluloses and lignin that occurred during steam explosion, bleaching and acid treatments. Surface morphological studies using SEM and AFM revealed that there was a reduction in fiber diameter during steam explosion followed by acid treatments. Percentage yield and aspect ratio of the nanofiber obtained by this technique is found to be very high in comparison with other conventional methods. TGA and DSC results showed that the developed nanofibers exhibit enhanced thermal properties over the untreated fibers.     

Steam pretreatment of lignocellulosic material for enhanced enzymatic hydrolysis

Pretreatment methods were compared with steam explosion, and differing views on the relative importance of mechanical and chemical effects were outlined. Hydrolysis was desirable; pyrolysis was undesirable. The effects of initial moisture content on steam consumption, mechanism and rate of heat transfer, pentosan solubilization, and subsequent glucose yield were summarized. The insignificant effect, after treatment at 240 degrees C, of 90% pressure bleed-down before explosion on subsequent simultaneous saccharification and fermentation (SSF) yields was described. Treatment at 190 degrees C with complete bleed-down (no explosion), when compared with that at 240 degrees C with explosion from full pressure, showed at least as good solubilizatoin of pentosan, enzymatic hydrolysis, and SSF but showed greater pentosan destruction for the same degree of pentosan removal. Water washing of unexploded steamed aspenwood chips was at least as efficient as that of similarly treated but exploded chips. Scanning electron micrographs of unexploded chips showed extensive rupturing of vessel pit membranes and other morphological features associated with steam-exploded wood. Neither the explosion nor the high temperatures (above 190 degrees C) are necessary.     

Effect of initial moisture content and chip size on the bioconversion efficiency of softwood lignocellulosics

Previous optimization strategies for the bioconversion of lignocellulosics by steam explosion technologies have focused on the effects of temperature, pH, and treatment time, but have not accounted for changes in severity brought about by properties inherent in the starting feedstock. Consequently, this study evaluated the effects of chip properties, feedstock size (40-mesh, 1.5 x 1.5 cm, 5 x 5 cm), and moisture content (12% and 30%) on the overall bioconversion process, and more specifically on the efficacy of removal of recalcitrant lignin from the lignocellulosic substrates following steam explosion. Increasing chip size resulted in an improvement in the solids recovery, with concurrent increases in the water soluble, hemicellulose-derived sugar recovery (7.5%). This increased recovery is a result of a decrease in the "relative severity" of the pretreatment as chip size increases. Additionally, the decreased relative severity minimized the condensation of the recalcitrant residual lignin and therefore increased the efficacy of peroxide fractionation, where a 60% improvement in lignin removal was possible with chips of larger initial size. Similarly, increased initial moisture content reduced the relative severity of the pretreatment, generating improved solids and hemicellulose-derived carbohydrate recovery. Both increased chip size and higher initial moisture content results in a substrate that performs better during peroxide delignification, and consequently enzymatic hydrolysis. Furthermore, a post steam-explosion refining step increased hemicellulose-derived sugar recovery and was most effectively delignified (to as low as 6.5%). The refined substrate could be enzymatically hydrolyzed to very high levels (98%) and relatively fast rates (1.23 g/L/h).     

Solvatochromic and electrokinetic studies of banana fibrils prepared from steam-exploded banana fiber

Steam explosion technique was used to isolate banana fibrils from banana fiber. The surface polarity of banana fiber, banana fibril, and chemically-treated banana fibril was investigated by ultraviolet/visible spectroscopy using solvatochromic probe dye molecules. The empirical Kamlet-Taft solvatochromic polarity parameters such as hydrogen bond donating ability HBD (alpha), hydrogen bond accepting ability HBA (beta), the dipolarity (pi*), Gutman acceptor number, and Reichardts ET(30) values for the banana fiber, banana fibril, and chemically-treated banana fibril were determined. It was observed that banana fibril has higher HBD value than banana fiber. Chemical treatment of the banana fibril has lowered the HBD value. The results of the empirical polarity parameters determined were found to be consistent with the results of electrokinetic measurements. The functional groups on the surface of banana fiber, banana fibril, and chemically-treated banana fibril was further analyzed using Fourier transform infrared spectroscopy (FTIR). FTIR spectra revealed the dissolution of the various components from the banana fiber after steam explosion which was further confirmed by scanning electron microscopy.     

木质纤维素预处理技术研究进展

详细评述了木质纤维素的预处理工艺研究进展,特别是浓酸低温水解-酸回收工艺、稀酸二阶段水解工艺、金属离子在稀酸水解过程中的助催化作用以及水蒸汽爆裂、氨纤维爆裂、CO2爆裂、酶催化水解等方法的研究进展情况。木质纤维素原料预处理技术发展为发酵生产乙醇技术的研究开发奠定了坚实基础。     

Effects of fungal pretreatment and steam explosion pretreatment on enzymatic saccharification of plant biomass

The effects of consecutive treatments by a lignin-degrading fungus Phanerochaete chrysosporium and by steam explosion for the enzymatic saccharification of plant biomass were studied experimentally, and the optimal operational conditions for obtaining the maximum saccharification were evaluated. Beech wood-meal was treated by the fungus for 98 days and then by high steam temperatures of 170-230 degrees C with steaming times of 0-10 min. The treatment of the wood-meal by fungus prior to steam explosion enhanced the saccharification of wood-meal. The treated wood-meal was separated into holo-cellulose, water soluble material, methanol soluble lignin, and Klason lignin. The saccharification decreased linearly with the increase in the amount of Klason lignin. It was estimated by the equation for the saccharification of exploded wood-meal expressed as a function of steam temperature and steaming time that the maximum saccharification of wood-meal was obtained by consecutive treatments such as fungal treatment for 28 days and then steam explosion at a steam temperature of 215 degrees C and a steaming time of 6.5 min. (c) 1995 John Wiley & Sons, Inc.     

Characterization of beta-glucosidase from corn stover and its application in simultaneous saccharification and fermentation

Purification and characterization of beta-glucosidase from corn stover was performed and the enzyme was tried in SSF to evaluate the suitability of plant glycosyl hydrolases in lignocellulose conversion. A beta-glucosidase with M(w) of 62.4 kDa was purified to homogeneity from post-harvest corn stover. The following physicochemical and kinetic parameters of the beta-glucosidase were studied respectively: optimum temperature, thermal stability, optimum pH, pH stability, K(m), V(max), V(i), cellobiose inhibition, tryptic peptide mass spectrometry and effect of metal ions and other reagents on the activity. The beta-glucosidase activity on salicin was optimal at pH 4.8 and 37 degrees C. The unique property of optimum temperature makes the beta-glucosidase potentially useful in SSF. In SSF of steam explosion pretreated corn stover, the supplementation of the purified beta-glucosidase was more effective than Aspergillus niger beta-glucosidase.     

The relationship between fiber-porosity and cellulose digestibility in steam-exploded Pinus radiata

Steam explosion after sulphur dioxide impregnation of wood chips is an effective method for improving the enzymatic digestibility of cellulose in the softwood Pinus radiata. Digestibility of pretreated fiber was progressively increased by altering the conditions of steam explosion. With increasing digestibility, there was an observed increase in fiber porosity as measured by the solute exclusion technique. Accessible pore volume and accessible surface area to a 5-nm dextran probe positively correlated with both 2- and 24-h digestion yields from pretreated fiber. The increase in accessibility was probably the result of hemicellulose extraction and lignin redistribution. A subsequent loss in accessibility, brought about by structural collapse or further lignin redistribution, resulted in a corresponding loss in digestibility. It appears that steam explosion increases cellulose digestibility in P. radiata by increasing fiber porosity.