用木质纤维原料生产乙醇的预处理工艺

预处理是利用木质生物资源生产乙醇的一个重要环节，纤维细胞的空隙度、纤维本身的结晶度、预处理温度、反应时间、pH值、纤维质原料的浓度对预处理产生影响，目前的预处理技术对木质生物资源的3种主要组分分离不完全且纤维素降解程度较高。今后对预处理的研究方向：有效分离出活性纤维，同时使半纤维素免遭破坏并充分利用，尽量减少对纤维素酶起抑制作用的降解产物的形成，减少能量消耗，降低成本，生产出高附加值的木素产品。     

木质纤维转化制燃料乙醇的研究进展

综述了蒸汽爆破、微波辅助等木质纤维原料的预处理方法,分析了木质纤维原料的酸水解与酶水解,总结了木质纤维原料发酵制取乙醇的三种最新发酵工艺,即同步糖化发酵、固定化细胞发酵、利用高效微生物发酵。我国在木质纤维原料生产燃料乙醇的技术应用已取得了重要进展,首次采用连续汽爆技术建设成500t/年纤维素乙醇产业化试验装置,河南建成首条年产3000t的纤维乙醇产业化试验生产线。     

氨纤维爆破法预处理木质纤维生物质原料

生物质预处理的目的是使紧密的原料组织变得疏松,以增加酶催化作用的表面积。氨纤维爆破(AFEX)是一种应用物理(高温高压)化学(氨水)工艺实现高效处理的方法。木质纤维素经AFEX预处理后,其纤维素结晶度降低,部分半纤维素解聚,木质素部分分解游离,原料表面水解特性增加。AFEX预处理和稀酸预处理相比减少了中和、脱毒等工艺,还可以减少发酵工艺中氮源的添加,因而作为一种新技术越来越受到重视。     

木质纤维素原料生产燃料乙醇预处理技术研究进展

对纤维质材料转化乙醇过程中的关键步骤--预处理技术的各种方法进行了综述,并对生物质预处理技术发展的前景进行了展望.     

秸秆制乙醇的休哈塔假丝酵母与酿酒酵母共混SSCF工艺优化

提出一种3阶段同步糖化共发酵(SSCF)工艺。采用0.9 mol/L丁酮溶液爆破法处理稻米秸秆,对休哈塔假丝酵母与酿酒酵母共混制乙醇工艺进行了优化与放大探讨。结果表明,用30 L通风发酵罐采用摇瓶发酵优化后的工艺条件,当爆破秸秆浓度8%(w/w);用15 U/g(绝干秸秆)纤维素酶、3.5 U/g(绝干秸秆)β-葡萄糖苷酶与12 U/g(绝干秸秆)木聚糖酶为混合酶酶解体系,在50℃搅拌下酶解25.1 h;接入8%酿酒酵母在37℃发酵34.1 h;再接入7.8%休哈塔假丝酵母在35℃、通风量0.3 L/(min·L)下混合发酵6 d时,乙醇收得率可达26.9 g/100 g(绝干秸秆),秸秆原料中葡萄糖、木糖能被分别利用91.4%与84.7%。该研究结果为无添加营养物发酵方法的应用以及木质纤维原料高效发酵转化为乙醇提供了参考。     

木质纤维原料预处理与水解技术的研究进展

木质纤维原料发酵中预处理和水解过程是提高可发酵性糖转化为乙醇的关键。对不同预处理和水解方法的优缺点进行了比较,并分析了不同预处理方法对水解过程的影响和水解液的脱毒处理。此外,还指出了预处理和水解方法的发展方向。     

木质纤维原料生产燃料乙醇的蒸汽爆破预处理技术

蒸汽爆破可破坏木质纤维结构,提高水解速率,是很有前景的生物质预处理技术。介绍了蒸汽爆破预处理的原理、影响因素及蒸汽爆破对底物及其后续酶水解的影响,并指出蒸汽爆破技术未来的研究方向。     

木质纤维素为原料制备乙醇的工艺

木质纤维素是秸秆的主要成分,将木质纤维素转换为清洁的可再生能源,不但可以缓解能源危机,而且对环境友好。文章介绍了国内外生物质能制备乙醇的研究进展,包括木质纤维素的预处理、水解、发酵和脱水工艺,对各种工艺的优缺点进行了论述。     

木质纤维素为原料制备乙醇的工艺

木质纤维素是秸秆的主要成分,将木质纤维素转换为清洁的可再生能源,不但可以缓解能源危机,而且对环境友好。文章介绍了国内外生物质能制备乙醇的研究进展,包括木质纤维素的预处理、水解、发酵和脱水工艺,对各种工艺的优缺点进行了论述。     

乙醇预处理前后玉米秸秆半纤维素的提取及性质研究

以玉米秸秆为原料,在温度160℃、保温时间60 min、乙醇浓度50%、固液比1∶8的条件下进行预处理,并对预处理前后的玉米秸秆进行半纤维素的提取和纯化。结果表明,乙醇预处理过程脱除了玉米秸秆中66.6%的Klason木素和61.3%的苯-醇抽出物,还降解了部分半纤维素和少量纤维素。在乙醇预处理过程中,半纤维素中的葡聚糖最易降解,聚阿拉伯糖次之,聚木糖最稳定,糖醛酸含量没有明显变化。结合红外光谱、紫外光谱、液相色谱等分析发现,乙醇预处理后半纤维素中含有较多的甲基、亚甲基单元,说明乙醇预处理造成玉米秸秆半纤维素降解,使半纤维素分子质量降低、多分散系数变大。     

木质纤维素原料预处理技术相关研究进展

木质纤维原料是地球上最丰富的可再生资源,开发木质纤维原料的应用必须经过不同预处理,但预处理过程中均会产生一些副产物,大多数会对后续的糖化及发酵具有抑制作用。针对不同木质纤维素原料采取的预处理方法进行了综合性分析,并阐述了预处理副产物的抑制机理,指出了最有效的抑制物解除方法。最后对如何选择成本低,产生副产物少,且纤维素回收率及酶解率高的预处理方法及其工业生产的应用前景进行了展望。     

稀碱法预处理橡子壳制备生物乙醇

考察了农林废弃物橡子壳作为原料发酵制备乙醇的可行性。研究了稀碱法预处理在不同条件下(温度、时间、浓度)对酶水解的影响。结果发现以2%Na OH,121℃(0.15 MPa)处理60 min的条件下预处理效果较好,木素去除率达到39.34%,经酶水解,单糖得率(葡萄糖、木糖、阿拉伯糖)达到606.36 mg/g(预处理原料)。经过嗜单宁管囊酵母发酵60 h,乙醇浓度达到11.96 g/L,为理论产率的85.4%。     

Comparison of common lignin methods and modifications on forage and lignocellulosic biomass materials

BACKGROUND: A variety of methods have been developed for estimating lignin concentration within plant materials. The objective of this study was to compare the lignin concentrations produced by six methods on a diverse population of forage and biomass materials and to examine the relationship between these concentrations and the portions of these materials that are available for utilisation by livestock or for ethanol conversion. RESULTS: Several methods produced lignin concentrations that were highly correlated with the digestibility of the forages, but there were few relationships between these methods and the available carbohydrate of the biomass materials. The use of Na₂SO₃ during preparation of residues for hydrolysis resulted in reduced lignin concentrations and decreased correlation with digestibility of forage materials, particularly the warm‐season grasses. CONCLUSION: There were several methods that were well suited for predicting the digestible portion of forage materials, with the acid detergent lignin and Klason lignin method giving the highest correlation across the three types of forage. The continued use of Na₂SO₃ during preparation of Van Soest fibres needs to be evaluated owing to its ability to reduce lignin concentrations and effectiveness in predicting the utilisation of feedstuffs and feedstocks. Because there was little correlation between the lignin concentration and the biomass materials, there is a need to examine alternative or develop new methods to estimate lignin concentrations that may be used to predict the availability of carbohydrates for ethanol conversion. Copyright © 2011 Society of Chemical Industry     

木质纤维素功能材料的研究进展

木材独特的多层级结构、优异的各向异性结构、良好的力学性能和微纳米通道,赋予其一系列非凡的性能,为功能材料的设计提供了更多可能.为提高木质纤维素资源的利用率和高值化转化,基于木质纤维素自身结构和理化性能,概述了木质纤维素在系列功能材料领域的发展,总结了结构设计及调控对木质纤维素功能材料性能的影响,综述了其在结构调控材料、...     

我国纤维素燃料乙醇产业发展现状

纤维素燃料乙醇作为生物燃料乙醇的未来发展方向,对国家能源多元化供应和温室气体减排具有积极的推动作用.目前我国对纤维素乙醇的研发在学术界和产业界都相当活跃,主流的工艺路线选择为预处理-酶解-发酵工艺.尽管许多项目已处于中试和产业化示范阶段,但诸如原料供应、预处理和纤维素酶等关键技术仍是阻碍纤维素乙醇产业化的瓶颈问题.     

A comparison of the 'glass'electrode and flame photometric methods for determining sodium in food materials

Summary. The 'glass'electrode technique and its application to environments likely to be encountered in food analysis is described. It is shown that the technique offers a rapid method of determining sodium concentration in the range 1 ppm to 2% in samples containing little or no protein. the 'glass'electrode and flame photometer methods, as carried out with the types of instrument likely to be available in control laboratories, are shown to be of comparable accuracy. Results obtained with the two techniques agree to 1-3%. the 'glass'electrode is shown to have certain advantages over the flame photometric technique, notably its freedom from interference by solid matter and chemical substances, resulting in simple and rapid sampling and calibrating procedures.     

Effective enzyme saccharification and ethanol production from Japanese cedar using various pretreatment methods

We investigated an effective method for the pretreatment of Japanese cedar for efficient enzymatic saccharification and ethanol production. A 45-atm steam explosion provided a comparatively large amount of glucose and reducing sugars. Addition of polyethylene glycol (PEG) influenced the digestibility of holocellulose in a 35-atm steam-exploded sample. However, we observed a negative effect on enzymatic saccharification when sodium hydroxide was used in the pretreatment. The maximum values of glucose and reducing sugars produced using consecutive pretreatments with a 25-atm steam explosion and an ionic liquid were 408 and 462 mg/(g initial dry sample), respectively. The most positive effects on the enzymatic saccharification kinetics were observed when the above consecutive pretreatment methods were used. However, using the organosolv treatment of wood chips without the steam explosion is a more cost-effective pretreatment method for the enzymatic saccharification of Japanese cedar, and this results in 386 and 426 mg/(g initial dry sample) of glucose and reducing sugars, respectively.