纤维素酶水解纤维素还原糖的测定

对不同类菌种在不同培养基中的酶活性进行比较,测定了其底物得糖率,最高达８．５９％,可对纤维素酶的进一步研究提供实验参照。     

纤维素类废弃物生物转化技术研究进展

纤维素类可再生性资源的生物转化研究是国际上竞相开展的重大研究课题，山东大学微生物研究所选择已对环境造成危害的造纸厂纤维素类废渣为突破口，开展了深入研究，取得了一系列重要进展．在利用亚硫酸铵法制浆黑液和细小纤维生产纤维素酶，蒸汽爆碎的半纤维素水解流发酵生产单细胞蛋白，备料废渣固态发酵生产蛋白质增富饲料，细小纤维和淀粉原料共发酵生产酒精等技术研究中取得了不少有创新的突破性进展，部分技术已开始转入中试和实际应用，为全面开发利用农林加工废弃物资源打下了良好的基础．     

木质纤维原料生物转化燃料乙醇的研究进展

木质纤维生物量能够用来生产一种可替代有限的石油产品的能源——乙醇。木质纤维的转化主要分两个步骤木质纤维生物量中纤维素水解生成还原糖;糖发酵成乙醇。基于目前的技术,木质纤维原料生产乙醇的主要问题是得率低、水解成本高。促进木质纤维水解的方法包括木质纤维原料预处理脱除木素和半纤维素;纤维素酶的优化;同步糖化发酵法(SSF)。     

天然植物原料改性聚氨酯及其应用

综述了含天然纤维素的植物原料在聚乙二醇和聚酯多元醇中进行液化及制备改性聚氨酯(PU)。介绍了植物纤维改性PU、玉米秸杆改性PU、稻草改性PU、甘蔗渣改性PU、树皮改性PU的性能及应用。重点介绍了树皮的主要成分单宁改性淀粉PU的耐水性、抗菌性和热稳定性。这些植物原料通过液化改性可替代部分石油多元醇,以满足性能各异的高附加值聚氨酯的要求及在卫生、家具、食品包装和保温隔热等领域中的应用。     

植物纤维原料纤维素酶水解的研究

以麦草为原料,探讨纤维素酶水解植物纤维的适宜条件。麦草含大量的纤维素和聚戊糖,其中的纤维素在纤维素酶的作用下分解生成葡萄糖和纤维二糖。对温度,pH值,酶解时间,酶用量分别进行单因素实验,通过测定葡萄糖含量和总还原糖含量,找出酶水解麦草的适宜条件为:pH4.6,温度47℃,酶解时间48h,酶用量7.5IU(每克绝干原料)。对不同底物浓度的实验表明,在尽可能高的底物浓度下连续水解,产物浓度高,得率也高。     

植物纤维素的限制性酶解特性

探讨了利用纤维素酶使纤维素棉浆粕限制性降解过程,得出优化反应条件如下:纤维素的酶解温度为50℃,纤维素酶解体系Ph值为4.8,酶解时间为24 h,底物与酶液的质量比为1:(6～10).     

用植物纤维素制备还原糖的工艺研究

本文以玉米芯为纤维素原料，利用蒸爆技术对纤维素料进行预处理。再进一步在纤维素酶催化下制备葡萄糖。     

真菌纤维素酶系催化纤维素水解活力的测定方法简介

<正>在测定纤维素粗酶样品对不溶性固体纤维素的水解活力时,尽管选用同一纤维素底物,并以同样的纤维素粗酶样品在相同温度下水解,测定结果受反应条件如纤维素底物浓度、纤维素酶浓度以及水解时间等因素的影响而相互差别很大。而纤维素粗酶作为多个纤维素酶组分的混合物,其糖化能力更加能够反应其中各个组分之间的协同水解转化能力。本文中选择了比底物水解率(SSC)作为纤维素酶浓度的函数,即单位纤维素酶每分钟对滤纸的水解百分比作为纤维素粗酶样品不同浓度的目的函数,从而克服了以上条件对纤维素酶活测定的影响。并以水解过程中SSC瞬时速率的AUC(Area under curve)对加入纤维素酶的量做图得到的斜率评价纤维素酶样品的水解能力。经检验,该方法也适用于以棉纤维、微晶纤维素PH101和磷酸膨胀纤维素等不同纤维材料为底物时纤维素酶粗酶样品糖化能力的测定。     

木质纤维素原料生产燃料酒精开发技术研究进展

在分析美国、日本、加拿大等国关于纤维素制取乙醇技术发展的基础上,对木质纤维素原料生产乙醇的预处理及水解为葡萄糖技术和纤维素原料发酵生产酒精生产技术、酒精废糟的处理利用进行了述评与讨论,对木质纤维素原料不同的预处理、水解和发酵方法进行了比较,展望了木质纤维素原料生产燃料酒精的前景.     

植物纤维素原料预处理技术的研究进展

对植物纤维素的原料的预处理方法进行了综述,物理方法中,机械粉碎是较常用的方法,但耗能较多;稀酸预处理能有效去除半纤维素,效率较高,但稀酸处理能耗较多且对设备的防腐要求较高;蒸汽爆破处理能有效地分离纤维素、半纤维和木质素,所处理物料酶解转化率高。     

Enzymatic conversion of irradiated cellulosic materials

Initial rate and degree of conversion in enzymatic hydrolysis of cellulosic materials (CM—cotton linter and bagasse) have complicated dependencies on dosage of γ-irradiation. The decrease in reactivity at low doses is explained by a decrease in the CM surface caused by radiation-induced crosslinkages. Doses higher than 0·5 MGy increased reactivity; at 2 MGy the degree of conversion (48 h hydrolysis) was about 5 times higher than in controls. Increased reactivity was caused by depolymerization, increased solubility and decrease of crystallinity index of CM.     

植物质生物转化发展近况

综述了生物转化天然植物质的研究和应用进展。介绍了植物质的预处理和酶解 ,纤维素酶及其测定 ,单细胞蛋白的生产 ,木质素的提取与应用等方面的研究近况     

Ignition and flash-fire studies of cellulosic materials

Various celloulosic materials were evaluated for ignitability and flash-fire propensity, using screening test methods developed at the University of San Francisco. Time to ignition, using radiation from a high-temperature radiant source without a pilot flame, appeared to be primarily a function of heat flux and material density, rather than of type of wood or celloulosic board. At heat flux levels from 5.8 to 10.5 W cm^?2, time to ignition was shortest for cellulose fiberboard with a density of 0.2225 g ml^?1, followed by western red cedar at 0.314 g ml^?1, eastern white pine at 0.348 g ml^?1, southern yellow pine at 0.422 g ml^?1, Douglas fir at 0.565 g ml ^?1, and longest for hardboard at 0.878 g ml^?1. For the cotton and rayon woven-pile upholstery fabrics, time to ignition appeared to increase with increasing fabric weight. For Cellulose insulation treated with boron-containing additives, flash-fire magnitude decreased with increasing additive content. Flash-fire magnitude decreased more that could be accounted for by decreasing weight loss alone, indication reduction in the combustibility of the volatiles produced. Reduction in flash-fire propensity of cotton bating by treatment with boron-containing additives was also observed.     

丙烯酰胺微生物转化过程和反应器形式的研究进展

回顾了近年来在丙烯酸胺微生物转化过程中反应器形式的研究进展，并对研究的发展方向提出了一些设想和展望。     

Cerium-initiated grafting of acrylonitrile onto cellulosic materials

Grafting of acrylonitrile onto native cotton, swollen cotton, viscose, ramie, and hydrocellulose was studied with tetravalent cerium as initiator. The effect of temperature on the graft yields is examined. With ceric ammonium nitrate the grafting yields are found to be higher at 20 and 40 than at 60°C. Ceric ammonium sulfate, on the other hand, produces more grafting at 60 than at 20 and 40°C. The consumption of ceric ions is less, whereas the per cent graft yields are higher for the swollen cottons and viscose than for native cotton. Graft yields are shown to be related to substrate accessibility if the grafting reaction is carried out under conditions that suppress homopolymerization. Oxidation of these celluloses with Ce^IV has also been studied. It is found that more Ce^IV is consumed during grafting than during oxidation of cellulose under identical reaction conditions. Excess Ce^IV consumed in the grafting reaction has been shown to be directly related to extent of homopolymerization, which accompanies grafting. Some data on the storage stability of the free-radical activity produced by oxidation of cellulose with Ce^IV are also reported. It is observed that the cerium-oxidized samples can initiate graft poly merization even after 4–5 hr. if stored in nitrogen.     

分散剂处理底物对甾体微生物转化体系的影响

考察了3种单组分分散剂PSE、MGE和OPG及其复配体系PSEMGE、PSEOPG和MGEOPG对甾体微生物转化体系的影响。试验表明:单组分分散剂PSE及复合型分散剂PSEMGE对甾体转化反应有利。其中单组分分散剂PSE的最佳施用量的质量分数为0.075%,复合型分散剂PSEMGE的最佳施用量因复配方式的不同而异。     

Molecular structure and ion exchange of amidoximated cellulosic materials

Modification of lignocellulosic materials, e.g., cotton stalks, bagasse, and rice straw, by incorporation of amidoxime group for ion exchange is investigated. The uptake of metal ions Cu, Cr, Ni, and Fe by these modified lignocellulosic materials is measured. Amidoximated bagasse has higher efficiency toward metal ions uptake than amidoximated cotton and rice straw. The effect of different variables, e.g., metal ion concentration, temperature of metal ion solution, and time of steeping, on the efficiency of the amidoximated (bagasse raw material, unbleached bagasse, and bleached bagasse) ion exchangers toward metal ions uptake is tested. The molecular structure of the prepared amidoxime from bagasse and its pulps is studied by using infrared spectroscopy. New bands appeared at 1661 and 916 cm^?1 in the spectra of amidoximated bagasse and its pulps ion exchangers due to the formation of C?N and N? OH groups. The thermal properties of these ion exchangers is also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 303–311, 2006