甘蔗生产燃料乙醇发酵技术的进展

乙醇是来自生物质资源的最有发展前景的液态燃料。以甘蔗原料生产燃料乙醇的产出量最具优势,发酵技术是甘蔗生产燃料乙醇的关键技术。详述了国内外甘蔗生产燃料乙醇的发酵技术的现状及进展。     

成都建成500亩燃料乙醇专用甘薯种薯繁育基地

生物质能源是四川省重点发展的＂十大优势特色种植业＂之一。生物质能源可利用的资源非常丰富,其中甘薯加工燃料乙醇是四川发展生物质能源的重要途径。甘薯经过发酵、精馏可生产纯度高达99.9%以上的乙醇．乙醇加入化学变性剂后与汽油按照一定比例混合（如在汽油中掺入10％的纯度为99．9％以上的乙醇）后就可得到乙醇汽油，这样，普通的甘薯就转化成了生物质液态燃料。     

甜菜乙醇实现工业化生产

<正>将甜菜洗净磨浆后加入一种生物酶与渣料一同发酵,蒸馏,最后产出高纯度乙醇。一项利用生物技术生产非粮食类生物乙醇工艺取得重大突破。香港和宝国际控股有限公司设在宁夏银川的生产示范基地两年的工业化生产实践证明,利用非粮食原料、低成本生产生物燃料乙醇巴成为可能。燃料乙醇是乙醇汽油的主要原料,由于是植物生产,因此被称为生物质可再生能源。按照"十一五"专项规划要求.燃料乙醇年产量要达到500万t。全国80%以上地区全部要封闭强制添加乙醇汽油。但是,直到2007年,我国燃料乙醇产量还仅为100多万t。     

广西非粮生物质能源产业发展现状及近期技术需求

介绍了广西非粮生物质燃料乙醇、生物沼气、颗粒燃料方面的产业发展现状与研发现状,分析了广西非粮生物质能源产业存在的主要技术问题,提出近期该产业的技术需求。     

多种原料路线的乙醇生产工艺

乙醇是一种成功的车用替代液体燃料,多种原料乙醇生产路线的技术研发及产业发展受到关注。主要综述了石油基乙烯、煤基合成气和纤维素类生物质3种原料生产乙醇的工艺技术进展,以及我国乙醇生产企业的技术水平和产业发展状况,并对多种原料的乙醇生产工艺技术的发展及应用进行了展望。     

基于酶水解的高效生物质乙醇生产过程的预处理技术

介绍了利用木质纤维原料生产乙醇的主要技术,并指出技术先进、低成本的预处理工艺所需达到的关键指标。与用淀粉或糖类生产生物质乙醇相比,用木质纤维原料生产生物质燃料（即第二代生物质乙醇）具有经济和环境方面的优势,但由于木质纤维原料主要组分较为紧密,阻碍了纤维素和半纤维素水解为可发酵糖的进程。预处理的主要目的是提高酶的可及性,从而提高纤维素降解率。每种预处理方法对纤维素、半纤维素和木素都有特定的影响,应根据后续水解和发酵工艺来确定预处理方法和条件。     

生物质能源的研究与发展

随着能源资源、粮食安全和环境恶化问题日益突出,全球能源的发展正步入一个新的阶段,全球能源结构正经历以矿物能源为主向可再生能源等多种能源并存的方向的变迁.第一代生物质能源--用粮食生产乙醇的发展规模必将受到限制,利用第二代生物质能源--纤维素类物质生产燃料乙醇已引起世界各国的高度重视.将纤维素生物质转化为燃料乙醇,可以降低对粮食安全的冲击,充分利用可再生资源可以减轻对石油的依赖、缓解环保的压力、促进农业的发展.     

燃料乙醇--酒精行业可持续发展之路

将乙醇脱水加入适量变性剂形成“变性燃料乙醇”，再和一定比例的汽油进一步混合，生产清洁燃料“车用燃料乙醇汽油”。“燃料乙醇”是一种可持续发展的绿色生物质能源，其生产可长期、稳定、有效地解决过剩农产品的转化、增值问题。以陈化粮食为原料生产“燃料乙醇”，走综合利用、综合开发、经济循环模式，可生产汽油、蛋白、汽水、饲料、沼气等产品，可降低燃料乙醇的生产成本，解决能源危机和实现保护环境，实现酒精行业的最佳经济效益的可持续发展。     

纤维素酶转化木质纤维素生物质生产乙醇的研究进展

木质纤维素生物质是价廉易得、来源丰富的可再生资源和能源，被纤维素酶转化后可以生产乙醇部分替代石油，这不仅有利于环境保护和资源再利用，而且可减少温室气体的排放和缓解化石能源的危机。纤维素酶成本的降低以及纤维素转化效率的提高是纤维素酶转化木质纤维素生物质生产乙醇的关键。本文综述了纤维素酶转化木质纤维素生物质生产乙醇的研究进展，主要包括纤维素酶的分类及其作用机制、纤维素酶的生产、木质纤维素生物质的预处理、纤维素酶的转化和糖化发酵乙醇工艺。     

动态通量平衡分析模拟酿酒酵母乙醇发酵工艺

生物乙醇是一种高效、清洁、安全的能源。酿酒酵母(S.cerevisiae)由于其生理特性而在生物乙醇发酵中广泛应用。利用动态通量平衡分析(DFBA)预测模拟了利用葡萄糖发酵产乙醇工艺中的关键参数,生物量、残糖浓度和乙醇生成。预测值与发酵实测值能够较好吻合。该方法为发酵工艺优化提供了计算机模拟优化的方法,也为利用其他底物,如纤维素、木糖等生物质发酵乙醇的理论模拟提供基础。     

Syngas fermentation in a 100-L pilot scale fermentor: Design and process considerations

Fermentation of syngas offers several advantages compared to chemical catalysts such as higher specificity of biocatalysts, lower energy costs, and higher carbon efficiency. Scale-up of syngas fermentation from a bench scale to a pilot scale fermentor is a critical step leading to commercialization. The primary objective of this research was to install and commission a pilot scale fermentor, and subsequently scale-up the Clostridium strain P11 fermentation from a 7.5-L fermentor to a pilot scale 100-L fermentor. Initial preparation and fermentations were conducted in strictly anaerobic conditions. The fermentation system was maintained in a batch mode with continuous syngas supply. The effect of anaerobic fermentation in a pilot scale fermentor was evaluated. In addition, the impact of improving the syngas mass transfer coefficient on the utilization and product formation was studied. Results indicate a six fold improvement in ethanol concentration compared to serum bottle fermentation, and formation of other compounds such as isopropyl alcohol, acetic acid and butanol, which are of commercial importance.     

合成气发酵产乙醇微生物菌群富集及微生物区系研究

为获得能够利用合成气发酵产乙醇的新菌株,分别从长臂猿、骆驼、豪猪和戴冕鹤4种动物粪便中连续富集培养获得了4个菌群（G-fm18、C-fm18、H-fm18、BP-fm18）,首先考察了种子液中少量木糖对于菌群合成气发酵的影响,然后对富集菌群进行变性梯度凝胶电泳（DGGE）微生物群落结构分析。结果表明,4种菌群均能够利用合成气发酵产生乙醇,且随着传代次数的增多,乙醇生产性能逐渐加强。种子液中携带的少量木糖可以显著促进合成气发酵菌群（菌株）的乙醇产量,种子液不离心后接种发酵的情况下,菌群G-fm18的乙醇产量最高为253.87 mg/L,约为离心发酵后乙醇产量的8倍。菌群G-fm18中主要含有一种不可培养细菌和芽孢杆菌;菌群C-fm18中主要含有一种不可培养细菌、芽孢杆菌、柠檬酸杆菌和瘤胃球菌;菌群H-fm18中主要含有肠杆菌;菌群BP-fm18中主要含有一种不可培养细菌、梭菌和气单孢菌。     

发展纤维素燃料乙醇势在必行

随着我国经济发展对石油进口的依赖程度不断加大,开发及提高替代能源比例已经迫在眉睫。作为替代能源之一的燃料乙醇目前国内开展的比较成熟,但粮食生产的燃料乙醇存在与民争地、征粮等现象,不适合全国推广。而纤维素原料生产燃料乙醇却有着得天独厚的条件的和广阔的发展前景,本文着重阐述了发展纤维素燃料的意义、用途及发展前景展望。     

替代原料发酵产生物丁醇及其他高级醇的研究进展

出于对能源安全和环境保护的考虑,利用替代原料通过微生物发酵生产丁醇及其他高级醇受到普遍关注。该文介绍了木纤维素,合成气,CO2,废弃蛋白质等潜在替代原料合成丁醇及其他高级醇等生物燃料的研究进展,并从发酵工艺的改进、提取工艺的优化、发酵菌株改良等方面综述了提高丁醇发酵效率的策略,以期为替代原料生产生物丁醇及其他高级醇研究提供新的思路。     

Land-use and alternative bioenergy pathways for waste biomass

Rapid escalation in biofuels consumption may lead to a trade regime that favors exports of food-based biofuels from tropical developing countries to developed countries. There is growing interest in mitigating the land-use impacts of these potential biofuels exports by converting biorefinery waste streams into cellulosic ethanol, potentially reducing the amount of land needed to meet production goals. This increased land-use efficiency for ethanol production may lower the land-use greenhouse gas emissions of ethanol but would come at the expense of converting the wastes into bioelectricity which may offset fossil fuel-based electricity and could provide a vital source of domestic electricity in developing countries. Here we compare these alternative uses of wastes with respect to environmental and energy security outcomes considering a range of electricity production efficiencies, ethanol yields, land-use scenarios, and energy offset assumptions. For a given amount of waste biomass, we found that using bioelectricity production to offset natural gas achieves 58% greater greenhouse gas reductions than using cellulosic ethanol to offset gasoline but similar emissions when cellulosic ethanol is used to offset the need for more sugar cane ethanol. If bioelectricity offsets low-carbon energy sources such as nuclear power then the liquid fuels pathway is preferred. Exports of cellulosic ethanol may have a small impact on the energy security of importing nations while bioelectricity production may have relatively large impacts on the energy security in developing countries.     

Environmental implications of municipal solid waste-derived ethanol

We model a municipal solid waste (MSW)-to-ethanol facility that employs dilute acid hydrolysis and gravity pressure vessel technology and estimate life cycle energy use and air emissions. We compare our results, assuming the ethanol is utilized as E85 (blended with 15% gasoline) in a light-duty vehicle, with extant life cycle assessments of gasoline, corn-ethanol, and energy crop-cellulosic-ethanol fueled vehicles. We also compare MSW-ethanol production, as a waste management alternative, with landfilling with gas recovery options. We find that the life cycle total energy use per vehicle mile traveled for MSW-ethanol is less than that of corn-ethanol and cellulosic-ethanol; and energy use from petroleum sources for MSW-ethanol is lower than for the other fuels. MSW-ethanol use in vehicles reduces net greenhouse gas (GHG) emissions by 65% compared to gasoline, and by 58% when compared to corn-ethanol. Relative GHG performance with respect to cellulosic ethanol depends on whether MSW classification is included or not. Converting MSW to ethanol will result in net fossil energy savings of 397-1830 MJ/MT MSW compared to net fossil energy consumption of 177-577 MJ/MT MSW for landfilling. However, landfilling with LFG recovery either for flaring or for electricity production results in greater reductions in GHG emissions compared to MSW-to-ethanol conversion.     

同步糖化浓醪发酵影响因素的探析

目前发酵法生产燃料乙醇普遍存在着成本较高，耗能过大的问题，解决这些问题已成为今后发酵法生产技术的发展方向。高浓度酒精发酵为生产企业提高经济效益，节约能源，保护环境起到积极的促进作用，在浓醪发酵工艺基础上，采取同步糖化工艺措施能够进一步降低原料消耗及综合能耗，符合燃料乙醇生产技术发展方向，具有重要的推广价值。充分探讨同步糖化发酵过程的影响因素，在工业装置上摸索出同步糖化浓醪发酵过程的控制手段，在传统发酵酒精浓度12％vol的基础上，发酵酒精浓度增加到14％vol。     

褐藻燃料乙醇研究进展及其应用前景

在生物质能源中,作为替代性再生能源之一的乙醇,具有燃烧安全、效率高、无污染等特点,燃料乙醇的研究开发已成为一项世界重大的热门课题.褐藻等藻类植物含有大量的碳水化合物,而这些碳水化合物能够被细菌、酵母菌等微生物直接或间接发酵转化为燃料乙醇.该文综述了利用海带、马尾藻等褐藻作为原料转化为乙醇的研究进展及其应用前景.     

Extraction with Ethanol as an Energy-Saving Alternative to Conventional Drying of Corn Starch

Drying of starch derived from corn wet-milling is an energy intensive operation in an energy intensive industry. An alternative to conventional drying involves extraction of water from the starch with an ethanol solution and reconcentration of the ethanol by distillation. Equilibrium data for starch with various concentrations of ethanol in water were obtained. These data were used to calculate the effect of multistage countercurrent extraction of mechanically dewatered starch using a mathematical model of the process. The energy required for drying the extracted starch and recovering the alcohol is predicted to be considerably less than that required for conventional drying. Energy savings up to 40% and more are possible.     

节能型乙醇脱水新技术研究进展

介绍了目前国外节能型乙醇脱水新技术的研究状况,主要有三种方法：精馏法、膜法和吸附法。分析了各种方法的分离原理、能耗及与工业化的距离。